sphinx.addnodesdocument)}( rawsourcechildren]( translations LanguagesNode)}(hhh](h pending_xref)}(hhh]docutils.nodesTextChinese (Simplified)}parenthsba attributes}(ids]classes]names]dupnames]backrefs] refdomainstdreftypedoc reftargetI/translations/zh_CN/networking/diagnostic/twisted_pair_layer1_diagnosticsmodnameN classnameN refexplicitutagnamehhh ubh)}(hhh]hChinese (Traditional)}hh2sbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftargetI/translations/zh_TW/networking/diagnostic/twisted_pair_layer1_diagnosticsmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hItalian}hhFsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftargetI/translations/it_IT/networking/diagnostic/twisted_pair_layer1_diagnosticsmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hJapanese}hhZsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftargetI/translations/ja_JP/networking/diagnostic/twisted_pair_layer1_diagnosticsmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hKorean}hhnsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftargetI/translations/ko_KR/networking/diagnostic/twisted_pair_layer1_diagnosticsmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hSpanish}hhsbah}(h]h ]h"]h$]h&] refdomainh)reftypeh+ reftargetI/translations/sp_SP/networking/diagnostic/twisted_pair_layer1_diagnosticsmodnameN classnameN refexplicituh1hhh ubeh}(h]h ]h"]h$]h&]current_languageEnglishuh1h hh _documenthsourceNlineNubhcomment)}(h SPDX-License-Identifier: GPL-2.0h]h SPDX-License-Identifier: GPL-2.0}hhsbah}(h]h ]h"]h$]h&] xml:spacepreserveuh1hhhhhhc/var/lib/git/docbuild/linux/Documentation/networking/diagnostic/twisted_pair_layer1_diagnostics.rsthKubhsection)}(hhh](htitle)}(hRDiagnostic Concept for Investigating Twisted Pair Ethernet Variants at OSI Layer 1h]hRDiagnostic Concept for Investigating Twisted Pair Ethernet Variants at OSI Layer 1}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhhhhhKubh)}(hhh](h)}(h Introductionh]h Introduction}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhhhhhKubh paragraph)}(h9This documentation is designed for two primary audiences:h]h9This documentation is designed for two primary audiences:}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhK hhhhubhenumerated_list)}(hhh](h list_item)}(hX**Users and System Administrators**: For those dealing with real-world Ethernet issues, this guide provides a practical, step-by-step troubleshooting flow to help identify and resolve common problems in Twisted Pair Ethernet at OSI Layer 1. If you're facing unstable links, speed drops, or mysterious network issues, jump right into the step-by-step guide and follow it through to find your solution. h]h)}(hX**Users and System Administrators**: For those dealing with real-world Ethernet issues, this guide provides a practical, step-by-step troubleshooting flow to help identify and resolve common problems in Twisted Pair Ethernet at OSI Layer 1. If you're facing unstable links, speed drops, or mysterious network issues, jump right into the step-by-step guide and follow it through to find your solution.h](hstrong)}(h#**Users and System Administrators**h]hUsers and System Administrators}(hhhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhubhXo: For those dealing with real-world Ethernet issues, this guide provides a practical, step-by-step troubleshooting flow to help identify and resolve common problems in Twisted Pair Ethernet at OSI Layer 1. If you’re facing unstable links, speed drops, or mysterious network issues, jump right into the step-by-step guide and follow it through to find your solution.}(hhhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK hhubah}(h]h ]h"]h$]h&]uh1hhhhhhhhNubh)}(hXH**Kernel Developers**: For developers working with network drivers and PHY support, this documentation outlines the diagnostic process and highlights areas where the Linux kernel’s diagnostic interfaces could be extended or improved. By understanding the diagnostic flow, developers can better prioritize future enhancements. h]h)}(hXG**Kernel Developers**: For developers working with network drivers and PHY support, this documentation outlines the diagnostic process and highlights areas where the Linux kernel’s diagnostic interfaces could be extended or improved. By understanding the diagnostic flow, developers can better prioritize future enhancements.h](h)}(h**Kernel Developers**h]hKernel Developers}(hj!hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhX2: For developers working with network drivers and PHY support, this documentation outlines the diagnostic process and highlights areas where the Linux kernel’s diagnostic interfaces could be extended or improved. By understanding the diagnostic flow, developers can better prioritize future enhancements.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjubah}(h]h ]h"]h$]h&]uh1hhhhhhhhNubeh}(h]h ]h"]h$]h&]enumtypearabicprefixhsuffix.uh1hhhhhhhhK ubeh}(h] introductionah ]h"] introductionah$]h&]uh1hhhhhhhhKubh)}(hhh](h)}(h;Step-by-Step Diagnostic Guide from Linux (General Ethernet)h]h;Step-by-Step Diagnostic Guide from Linux (General Ethernet)}(hjUhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjRhhhhhKubh)}(hXQThis diagnostic guide covers common Ethernet troubleshooting scenarios, focusing on **link stability and detection** across different Ethernet environments, including **Single-Pair Ethernet (SPE)** and **Multi-Pair Ethernet (MPE)**, as well as power delivery technologies like **PoDL** (Power over Data Line) and **PoE** (Clause 33 PSE).h](hTThis diagnostic guide covers common Ethernet troubleshooting scenarios, focusing on }(hjchhhNhNubh)}(h **link stability and detection**h]hlink stability and detection}(hjkhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjcubh3 across different Ethernet environments, including }(hjchhhNhNubh)}(h**Single-Pair Ethernet (SPE)**h]hSingle-Pair Ethernet (SPE)}(hj}hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjcubh and }(hjchhhNhNubh)}(h**Multi-Pair Ethernet (MPE)**h]hMulti-Pair Ethernet (MPE)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjcubh., as well as power delivery technologies like }(hjchhhNhNubh)}(h**PoDL**h]hPoDL}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjcubh (Power over Data Line) and }(hjchhhNhNubh)}(h**PoE**h]hPoE}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjcubh (Clause 33 PSE).}(hjchhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjRhhubh)}(hThe guide is designed to help users diagnose physical layer (Layer 1) issues on systems running **Linux kernel version 6.11 or newer**, utilizing **ethtool version 6.10 or later** and **iproute2 version 6.4.0 or later**.h](h`The guide is designed to help users diagnose physical layer (Layer 1) issues on systems running }(hjhhhNhNubh)}(h&**Linux kernel version 6.11 or newer**h]h"Linux kernel version 6.11 or newer}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh , utilizing }(hjhhhNhNubh)}(h!**ethtool version 6.10 or later**h]hethtool version 6.10 or later}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh and }(hjhhhNhNubh)}(h#**iproute2 version 6.4.0 or later**h]hiproute2 version 6.4.0 or later}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK!hjRhhubh)}(hIn this guide, we assume that users may have **limited or no access to the link partner** and will focus on diagnosing issues locally.h](h-In this guide, we assume that users may have }(hjhhhNhNubh)}(h,**limited or no access to the link partner**h]h(limited or no access to the link partner}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh- and will focus on diagnosing issues locally.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK%hjRhhubh)}(hhh](h)}(hDiagnostic Scenariosh]hDiagnostic Scenarios}(hj2hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj/hhhhhK)ubh bullet_list)}(hhh](h)}(h**Link is up and stable, but no data transfer**: If the link is stable but there are issues with data transmission, refer to the **OSI Layer 2 Troubleshooting Guide**. h]h)}(h**Link is up and stable, but no data transfer**: If the link is stable but there are issues with data transmission, refer to the **OSI Layer 2 Troubleshooting Guide**.h](h)}(h/**Link is up and stable, but no data transfer**h]h+Link is up and stable, but no data transfer}(hjMhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjIubhR: If the link is stable but there are issues with data transmission, refer to the }(hjIhhhNhNubh)}(h%**OSI Layer 2 Troubleshooting Guide**h]h!OSI Layer 2 Troubleshooting Guide}(hj_hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjIubh.}(hjIhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK+hjEubah}(h]h ]h"]h$]h&]uh1hhjBhhhhhNubh)}(h**Link is unstable**: Link resets, speed drops, or other fluctuations indicate potential issues at the hardware or physical layer. h]h)}(h**Link is unstable**: Link resets, speed drops, or other fluctuations indicate potential issues at the hardware or physical layer.h](h)}(h**Link is unstable**h]hLink is unstable}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhn: Link resets, speed drops, or other fluctuations indicate potential issues at the hardware or physical layer.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK/hj}ubah}(h]h ]h"]h$]h&]uh1hhjBhhhhhNubh)}(hG**No link detected**: The interface is up, but no link is established. h]h)}(hF**No link detected**: The interface is up, but no link is established.h](h)}(h**No link detected**h]hNo link detected}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh2: The interface is up, but no link is established.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK2hjubah}(h]h ]h"]h$]h&]uh1hhjBhhhhhNubeh}(h]h ]h"]h$]h&]bullet-uh1j@hhhK+hj/hhubeh}(h]diagnostic-scenariosah ]h"]diagnostic scenariosah$]h&]uh1hhjRhhhhhK)ubh)}(hhh](h)}(hVerify Interface Statush]hVerify Interface Status}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhK5ubh)}(hXkBegin by verifying the status of the Ethernet interface to check if it is administratively up. Unlike `ethtool`, which provides information on the link and PHY status, it does not show the **administrative state** of the interface. To check this, you should use the `ip` command, which describes the interface state within the angle brackets `"<>"` in its output.h](hfBegin by verifying the status of the Ethernet interface to check if it is administratively up. Unlike }(hjhhhNhNubhtitle_reference)}(h `ethtool`h]hethtool}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubhN, which provides information on the link and PHY status, it does not show the }(hjhhhNhNubh)}(h**administrative state**h]hadministrative state}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh5 of the interface. To check this, you should use the }(hjhhhNhNubj)}(h`ip`h]hip}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubhH command, which describes the interface state within the angle brackets }(hjhhhNhNubj)}(h`"<>"`h]h“<>”}(hj*hhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubh in its output.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK7hjhhubh)}(h]For example, in the output ``, the important keywords are:h](hFor example, in the output }(hjBhhhNhNubj)}(h%``h]h#}(hjJhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjBubh, the important keywords are:}(hjBhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK=hjhhubjA)}(hhh](h)}(h:**UP**: The interface is in the administrative "UP" state.h]h)}(hjgh](h)}(h**UP**h]hUP}(hjlhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjiubh8: The interface is in the administrative “UP” state.}(hjihhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK@hjeubah}(h]h ]h"]h$]h&]uh1hhjbhhhhhNubh)}(hX**NO-CARRIER**: The interface is administratively up, but no physical link is detected. h]h)}(hW**NO-CARRIER**: The interface is administratively up, but no physical link is detected.h](h)}(h**NO-CARRIER**h]h NO-CARRIER}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhI: The interface is administratively up, but no physical link is detected.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKAhjubah}(h]h ]h"]h$]h&]uh1hhjbhhhhhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhK@hjhhubh)}(hpIf the output shows ``, this indicates the interface is in the administrative "DOWN" state.h](hIf the output shows }(hjhhhNhNubj)}(h``h]h}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubhI, this indicates the interface is in the administrative “DOWN” state.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKDhjhhubjA)}(hhh](h)}(h,**Command:** `ip link show dev ` h]h)}(h+**Command:** `ip link show dev `h](h)}(h **Command:**h]hCommand:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh }(hjhhhNhNubj)}(h`ip link show dev `h]hip link show dev }(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1hhhhKGhjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(h**Expected Output:** .. code-block:: bash 4: eth0: mtu 1500 ... link/ether 88:14:2b:00:96:f2 brd ff:ff:ff:ff:ff:ff h](h)}(h**Expected Output:**h]h)}(hjh]hExpected Output:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]uh1hhhhKIhj ubh literal_block)}(ho4: eth0: mtu 1500 ... link/ether 88:14:2b:00:96:f2 brd ff:ff:ff:ff:ff:ffh]ho4: eth0: mtu 1500 ... link/ether 88:14:2b:00:96:f2 brd ff:ff:ff:ff:ff:ff}hj*sbah}(h]h ]h"]h$]h&]hhforcelanguagebashhighlight_args}uh1j(hhhKKhj ubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hX%**Interpreting the Output:** - **Administrative UP State**: - If the output contains **"UP"**, the interface is administratively up, and the system is trying to establish a physical link. - If you also see **"NO-CARRIER"**, it means the physical link has not been detected, indicating potential Layer 1 issues like a cable fault, misconfiguration, or no connection at the link partner. In this case, proceed to the **Inspect Link Status and PHY Configuration** section. - **Administrative DOWN State**: - If the output lacks **"UP"** and shows only states like **""**, it means the interface is administratively down. In this case, bring the interface up using the following command: .. code-block:: bash ip link set dev up h](h)}(h**Interpreting the Output:**h]h)}(hjIh]hInterpreting the Output:}(hjKhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjGubah}(h]h ]h"]h$]h&]uh1hhhhKPhjCubjA)}(hhh](h)}(hX**Administrative UP State**: - If the output contains **"UP"**, the interface is administratively up, and the system is trying to establish a physical link. - If you also see **"NO-CARRIER"**, it means the physical link has not been detected, indicating potential Layer 1 issues like a cable fault, misconfiguration, or no connection at the link partner. In this case, proceed to the **Inspect Link Status and PHY Configuration** section. h](h)}(h**Administrative UP State**:h](h)}(h**Administrative UP State**h]hAdministrative UP State}(hjihhhNhNubah}(h]h ]h"]h$]h&]uh1hhjeubh:}(hjehhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKRhjaubjA)}(hhh](h)}(h~If the output contains **"UP"**, the interface is administratively up, and the system is trying to establish a physical link. h]h)}(h}If the output contains **"UP"**, the interface is administratively up, and the system is trying to establish a physical link.h](hIf the output contains }(hjhhhNhNubh)}(h**"UP"**h]h“UP”}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh^, the interface is administratively up, and the system is trying to establish a physical link.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKThjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(hXIf you also see **"NO-CARRIER"**, it means the physical link has not been detected, indicating potential Layer 1 issues like a cable fault, misconfiguration, or no connection at the link partner. In this case, proceed to the **Inspect Link Status and PHY Configuration** section. h]h)}(hXIf you also see **"NO-CARRIER"**, it means the physical link has not been detected, indicating potential Layer 1 issues like a cable fault, misconfiguration, or no connection at the link partner. In this case, proceed to the **Inspect Link Status and PHY Configuration** section.h](hIf you also see }(hjhhhNhNubh)}(h**"NO-CARRIER"**h]h“NO-CARRIER”}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh, it means the physical link has not been detected, indicating potential Layer 1 issues like a cable fault, misconfiguration, or no connection at the link partner. In this case, proceed to the }(hjhhhNhNubh)}(h-**Inspect Link Status and PHY Configuration**h]h)Inspect Link Status and PHY Configuration}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh section.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKWhjubah}(h]h ]h"]h$]h&]uh1hhjubeh}(h]h ]h"]h$]h&]jjuh1j@hhhKThjaubeh}(h]h ]h"]h$]h&]uh1hhj^ubh)}(hX+**Administrative DOWN State**: - If the output lacks **"UP"** and shows only states like **""**, it means the interface is administratively down. In this case, bring the interface up using the following command: .. code-block:: bash ip link set dev up h](h)}(h**Administrative DOWN State**:h](h)}(h**Administrative DOWN State**h]hAdministrative DOWN State}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK\hjubjA)}(hhh]h)}(hXIf the output lacks **"UP"** and shows only states like **""**, it means the interface is administratively down. In this case, bring the interface up using the following command: .. code-block:: bash ip link set dev up h](h)}(hIf the output lacks **"UP"** and shows only states like **""**, it means the interface is administratively down. In this case, bring the interface up using the following command:h](hIf the output lacks }(hjhhhNhNubh)}(h**"UP"**h]h“UP”}(hj%hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh and shows only states like }(hjhhhNhNubh)}(h**""**h]h“”}(hj7hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubht, it means the interface is administratively down. In this case, bring the interface up using the following command:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK^hjubj))}(hip link set dev uph]hip link set dev up}hjOsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhKbhjubeh}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhK^hjubeh}(h]h ]h"]h$]h&]uh1hhj^ubeh}(h]h ]h"]h$]h&]jjuh1j@hhhKRhjCubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hXy**Next Steps**: - If the interface is **administratively up** but shows **NO-CARRIER**, proceed to the **Inspect Link Status and PHY Configuration** section to troubleshoot potential physical layer issues. - If the interface was **administratively down** and you have brought it up, ensure to **repeat this verification step** to confirm the new state of the interface before proceeding - **If the interface is up and the link is detected**: - If the output shows **"UP"** and there is **no `NO-CARRIER`**, the interface is administratively up, and the physical link has been successfully established. If everything is working as expected, the Layer 1 diagnostics are complete, and no further action is needed. - If the interface is up and the link is detected but **no data is being transferred**, the issue is likely beyond Layer 1, and you should proceed with diagnosing the higher layers of the OSI model. This may involve checking Layer 2 configurations (such as VLANs or MAC address issues), Layer 3 settings (like IP addresses, routing, or ARP), or Layer 4 and above (firewalls, services, etc.). - If the **link is unstable** or **frequently resetting or dropping**, this may indicate a physical layer issue such as a faulty cable, interference, or power delivery problems. In this case, proceed with the next step in this guide. h](h)}(h**Next Steps**:h](h)}(h**Next Steps**h]h Next Steps}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKfhj}ubjA)}(hhh](h)}(hIf the interface is **administratively up** but shows **NO-CARRIER**, proceed to the **Inspect Link Status and PHY Configuration** section to troubleshoot potential physical layer issues. h]h)}(hIf the interface is **administratively up** but shows **NO-CARRIER**, proceed to the **Inspect Link Status and PHY Configuration** section to troubleshoot potential physical layer issues.h](hIf the interface is }(hjhhhNhNubh)}(h**administratively up**h]hadministratively up}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh but shows }(hjhhhNhNubh)}(h**NO-CARRIER**h]h NO-CARRIER}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh, proceed to the }(hjhhhNhNubh)}(h-**Inspect Link Status and PHY Configuration**h]h)Inspect Link Status and PHY Configuration}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh9 section to troubleshoot potential physical layer issues.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(hIf the interface was **administratively down** and you have brought it up, ensure to **repeat this verification step** to confirm the new state of the interface before proceeding h]h)}(hIf the interface was **administratively down** and you have brought it up, ensure to **repeat this verification step** to confirm the new state of the interface before proceedingh](hIf the interface was }(hjhhhNhNubh)}(h**administratively down**h]hadministratively down}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh' and you have brought it up, ensure to }(hjhhhNhNubh)}(h!**repeat this verification step**h]hrepeat this verification step}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh< to confirm the new state of the interface before proceeding}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKlhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(hX**If the interface is up and the link is detected**: - If the output shows **"UP"** and there is **no `NO-CARRIER`**, the interface is administratively up, and the physical link has been successfully established. If everything is working as expected, the Layer 1 diagnostics are complete, and no further action is needed. - If the interface is up and the link is detected but **no data is being transferred**, the issue is likely beyond Layer 1, and you should proceed with diagnosing the higher layers of the OSI model. This may involve checking Layer 2 configurations (such as VLANs or MAC address issues), Layer 3 settings (like IP addresses, routing, or ARP), or Layer 4 and above (firewalls, services, etc.). - If the **link is unstable** or **frequently resetting or dropping**, this may indicate a physical layer issue such as a faulty cable, interference, or power delivery problems. In this case, proceed with the next step in this guide. h](h)}(h4**If the interface is up and the link is detected**:h](h)}(h3**If the interface is up and the link is detected**h]h/If the interface is up and the link is detected}(hj2hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj.ubh:}(hj.hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKphj*ubjA)}(hhh](h)}(hX If the output shows **"UP"** and there is **no `NO-CARRIER`**, the interface is administratively up, and the physical link has been successfully established. If everything is working as expected, the Layer 1 diagnostics are complete, and no further action is needed. h]h)}(hX If the output shows **"UP"** and there is **no `NO-CARRIER`**, the interface is administratively up, and the physical link has been successfully established. If everything is working as expected, the Layer 1 diagnostics are complete, and no further action is needed.h](hIf the output shows }(hjQhhhNhNubh)}(h**"UP"**h]h“UP”}(hjYhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjQubh and there is }(hjQhhhNhNubh)}(h**no `NO-CARRIER`**h]hno `NO-CARRIER`}(hjkhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjQubh, the interface is administratively up, and the physical link has been successfully established. If everything is working as expected, the Layer 1 diagnostics are complete, and no further action is needed.}(hjQhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKrhjMubah}(h]h ]h"]h$]h&]uh1hhjJubh)}(hXIf the interface is up and the link is detected but **no data is being transferred**, the issue is likely beyond Layer 1, and you should proceed with diagnosing the higher layers of the OSI model. This may involve checking Layer 2 configurations (such as VLANs or MAC address issues), Layer 3 settings (like IP addresses, routing, or ARP), or Layer 4 and above (firewalls, services, etc.). h]h)}(hXIf the interface is up and the link is detected but **no data is being transferred**, the issue is likely beyond Layer 1, and you should proceed with diagnosing the higher layers of the OSI model. This may involve checking Layer 2 configurations (such as VLANs or MAC address issues), Layer 3 settings (like IP addresses, routing, or ARP), or Layer 4 and above (firewalls, services, etc.).h](h4If the interface is up and the link is detected but }(hjhhhNhNubh)}(h **no data is being transferred**h]hno data is being transferred}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhX1, the issue is likely beyond Layer 1, and you should proceed with diagnosing the higher layers of the OSI model. This may involve checking Layer 2 configurations (such as VLANs or MAC address issues), Layer 3 settings (like IP addresses, routing, or ARP), or Layer 4 and above (firewalls, services, etc.).}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKwhjubah}(h]h ]h"]h$]h&]uh1hhjJubh)}(hIf the **link is unstable** or **frequently resetting or dropping**, this may indicate a physical layer issue such as a faulty cable, interference, or power delivery problems. In this case, proceed with the next step in this guide. h]h)}(hIf the **link is unstable** or **frequently resetting or dropping**, this may indicate a physical layer issue such as a faulty cable, interference, or power delivery problems. In this case, proceed with the next step in this guide.h](hIf the }(hjhhhNhNubh)}(h**link is unstable**h]hlink is unstable}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh or }(hjhhhNhNubh)}(h$**frequently resetting or dropping**h]h frequently resetting or dropping}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh, this may indicate a physical layer issue such as a faulty cable, interference, or power delivery problems. In this case, proceed with the next step in this guide.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhK~hjubah}(h]h ]h"]h$]h&]uh1hhjJubeh}(h]h ]h"]h$]h&]jjuh1j@hhhKrhj*ubeh}(h]h ]h"]h$]h&]uh1hhjubeh}(h]h ]h"]h$]h&]jjuh1j@hhhKhhj}ubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhKGhjhhubeh}(h]verify-interface-statusah ]h"]verify interface statusah$]h&]uh1hhjRhhhhhK5ubh)}(hhh](h)}(h)Inspect Link Status and PHY Configurationh]h)Inspect Link Status and PHY Configuration}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhKubh)}(hX Use `ethtool -I` to check the link status, PHY configuration, supported link modes, and additional statistics such as the **Link Down Events** counter. This step is essential for diagnosing Layer 1 problems such as speed mismatches, duplex issues, and link instability.h](hUse }(hj&hhhNhNubj)}(h `ethtool -I`h]h ethtool -I}(hj.hhhNhNubah}(h]h ]h"]h$]h&]uh1jhj&ubhj to check the link status, PHY configuration, supported link modes, and additional statistics such as the }(hj&hhhNhNubh)}(h**Link Down Events**h]hLink Down Events}(hj@hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj&ubh counter. This step is essential for diagnosing Layer 1 problems such as speed mismatches, duplex issues, and link instability.}(hj&hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubh)}(hXWFor both **Single-Pair Ethernet (SPE)** and **Multi-Pair Ethernet (MPE)** devices, you will use this step to gather key details about the link. **SPE** links generally support a single speed and mode without autonegotiation (with the exception of **10BaseT1L**), while **MPE** devices typically support multiple link modes and autonegotiation.h](h For both }(hjXhhhNhNubh)}(h**Single-Pair Ethernet (SPE)**h]hSingle-Pair Ethernet (SPE)}(hj`hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjXubh and }(hjXhhhNhNubh)}(h**Multi-Pair Ethernet (MPE)**h]hMulti-Pair Ethernet (MPE)}(hjrhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjXubhG devices, you will use this step to gather key details about the link. }(hjXhhhNhNubh)}(h**SPE**h]hSPE}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjXubh` links generally support a single speed and mode without autonegotiation (with the exception of }(hjXhhhNhNubh)}(h **10BaseT1L**h]h 10BaseT1L}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjXubh ), while }(hjXhhhNhNubh)}(h**MPE**h]hMPE}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjXubhC devices typically support multiple link modes and autonegotiation.}(hjXhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjhhubjA)}(hhh](h)}(h&**Command:** `ethtool -I ` h]h)}(h%**Command:** `ethtool -I `h](h)}(h **Command:**h]hCommand:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh }(hjhhhNhNubj)}(h`ethtool -I `h]hethtool -I }(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1hhhhKhjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(hX+**Example Output for SPE Interface (Non-autonegotiation)**: .. code-block:: bash Settings for spe4: Supported ports: [ TP ] Supported link modes: 100baseT1/Full Supported pause frame use: No Supports auto-negotiation: No Supported FEC modes: Not reported Advertised link modes: Not applicable Advertised pause frame use: No Advertised auto-negotiation: No Advertised FEC modes: Not reported Speed: 100Mb/s Duplex: Full Auto-negotiation: off master-slave cfg: forced slave master-slave status: slave Port: Twisted Pair PHYAD: 6 Transceiver: external MDI-X: Unknown Supports Wake-on: d Wake-on: d Link detected: yes SQI: 7/7 Link Down Events: 2 h](h)}(h;**Example Output for SPE Interface (Non-autonegotiation)**:h](h)}(h:**Example Output for SPE Interface (Non-autonegotiation)**h]h6Example Output for SPE Interface (Non-autonegotiation)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjubj))}(hXSettings for spe4: Supported ports: [ TP ] Supported link modes: 100baseT1/Full Supported pause frame use: No Supports auto-negotiation: No Supported FEC modes: Not reported Advertised link modes: Not applicable Advertised pause frame use: No Advertised auto-negotiation: No Advertised FEC modes: Not reported Speed: 100Mb/s Duplex: Full Auto-negotiation: off master-slave cfg: forced slave master-slave status: slave Port: Twisted Pair PHYAD: 6 Transceiver: external MDI-X: Unknown Supports Wake-on: d Wake-on: d Link detected: yes SQI: 7/7 Link Down Events: 2h]hXSettings for spe4: Supported ports: [ TP ] Supported link modes: 100baseT1/Full Supported pause frame use: No Supports auto-negotiation: No Supported FEC modes: Not reported Advertised link modes: Not applicable Advertised pause frame use: No Advertised auto-negotiation: No Advertised FEC modes: Not reported Speed: 100Mb/s Duplex: Full Auto-negotiation: off master-slave cfg: forced slave master-slave status: slave Port: Twisted Pair PHYAD: 6 Transceiver: external MDI-X: Unknown Supports Wake-on: d Wake-on: d Link detected: yes SQI: 7/7 Link Down Events: 2}hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhKhjubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hX**Example Output for MPE Interface (Autonegotiation)**: .. code-block:: bash Settings for eth1: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Supported pause frame use: Symmetric Receive-only Supports auto-negotiation: Yes Supported FEC modes: Not reported Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Advertised pause frame use: Symmetric Receive-only Advertised auto-negotiation: Yes Advertised FEC modes: Not reported Link partner advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Link partner advertised pause frame use: Symmetric Receive-only Link partner advertised auto-negotiation: Yes Link partner advertised FEC modes: Not reported Speed: 100Mb/s Duplex: Full Auto-negotiation: on Port: Twisted Pair PHYAD: 10 Transceiver: internal MDI-X: Unknown Supports Wake-on: pg Wake-on: p Link detected: yes Link Down Events: 1 h](h)}(h7**Example Output for MPE Interface (Autonegotiation)**:h](h)}(h6**Example Output for MPE Interface (Autonegotiation)**h]h2Example Output for MPE Interface (Autonegotiation)}(hj5hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj1ubh:}(hj1hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhj-ubj))}(hX+Settings for eth1: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Supported pause frame use: Symmetric Receive-only Supports auto-negotiation: Yes Supported FEC modes: Not reported Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Advertised pause frame use: Symmetric Receive-only Advertised auto-negotiation: Yes Advertised FEC modes: Not reported Link partner advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Link partner advertised pause frame use: Symmetric Receive-only Link partner advertised auto-negotiation: Yes Link partner advertised FEC modes: Not reported Speed: 100Mb/s Duplex: Full Auto-negotiation: on Port: Twisted Pair PHYAD: 10 Transceiver: internal MDI-X: Unknown Supports Wake-on: pg Wake-on: p Link detected: yes Link Down Events: 1h]hX+Settings for eth1: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Supported pause frame use: Symmetric Receive-only Supports auto-negotiation: Yes Supported FEC modes: Not reported Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Advertised pause frame use: Symmetric Receive-only Advertised auto-negotiation: Yes Advertised FEC modes: Not reported Link partner advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Link partner advertised pause frame use: Symmetric Receive-only Link partner advertised auto-negotiation: Yes Link partner advertised FEC modes: Not reported Speed: 100Mb/s Duplex: Full Auto-negotiation: on Port: Twisted Pair PHYAD: 10 Transceiver: internal MDI-X: Unknown Supports Wake-on: pg Wake-on: p Link detected: yes Link Down Events: 1}hjMsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhKhj-ubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hXP**Next Steps**: - Record the output provided by `ethtool`, particularly noting the **master-slave status**, **speed**, **duplex**, and other relevant fields. This information will be useful for further analysis or troubleshooting. Once the **ethtool** output has been collected and stored, move on to the next diagnostic step. h](h)}(h**Next Steps**:h](h)}(h**Next Steps**h]h Next Steps}(hjkhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjgubh:}(hjghhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjcubjA)}(hhh]h)}(hX5Record the output provided by `ethtool`, particularly noting the **master-slave status**, **speed**, **duplex**, and other relevant fields. This information will be useful for further analysis or troubleshooting. Once the **ethtool** output has been collected and stored, move on to the next diagnostic step. h]h)}(hX4Record the output provided by `ethtool`, particularly noting the **master-slave status**, **speed**, **duplex**, and other relevant fields. This information will be useful for further analysis or troubleshooting. Once the **ethtool** output has been collected and stored, move on to the next diagnostic step.h](hRecord the output provided by }(hjhhhNhNubj)}(h `ethtool`h]hethtool}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubh, particularly noting the }(hjhhhNhNubh)}(h**master-slave status**h]hmaster-slave status}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh, }(hjhhhNhNubh)}(h **speed**h]hspeed}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh, }hjsbh)}(h **duplex**h]hduplex}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubho, and other relevant fields. This information will be useful for further analysis or troubleshooting. Once the }(hjhhhNhNubh)}(h **ethtool**h]hethtool}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhK output has been collected and stored, move on to the next diagnostic step.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjubah}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhKhjcubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhKhjhhubeh}(h])inspect-link-status-and-phy-configurationah ]h"])inspect link status and phy configurationah$]h&]uh1hhjRhhhhhKubh)}(hhh](h)}(h"Check Power Delivery (PoDL or PoE)h]h"Check Power Delivery (PoDL or PoE)}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj hhhhhKubh)}(hXIf it is known that **PoDL** or **PoE** is **not implemented** on the system, or the **PSE** (Power Sourcing Equipment) is managed by proprietary user-space software or external tools, you can skip this step. In such cases, verify power delivery through alternative methods, such as checking hardware indicators (LEDs), using multimeters, or consulting vendor-specific software for monitoring power status.h](hIf it is known that }(hj# hhhNhNubh)}(h**PoDL**h]hPoDL}(hj+ hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj# ubh or }(hj# hhhNhNubh)}(h**PoE**h]hPoE}(hj= hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj# ubh is }(hj# hhhNhNubh)}(h**not implemented**h]hnot implemented}(hjO hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj# ubh on the system, or the }(hj# hhhNhNubh)}(h**PSE**h]hPSE}(hja hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj# ubhX: (Power Sourcing Equipment) is managed by proprietary user-space software or external tools, you can skip this step. In such cases, verify power delivery through alternative methods, such as checking hardware indicators (LEDs), using multimeters, or consulting vendor-specific software for monitoring power status.}(hj# hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhj hhubh)}(hIf **PoDL** or **PoE** is implemented and managed directly by Linux, follow these steps to ensure power is being delivered correctly:h](hIf }(hjy hhhNhNubh)}(h**PoDL**h]hPoDL}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjy ubh or }(hjy hhhNhNubh)}(h**PoE**h]hPoE}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjy ubho is implemented and managed directly by Linux, follow these steps to ensure power is being delivered correctly:}(hjy hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhj hhubjA)}(hhh](h)}(h.**Command:** `ethtool --show-pse ` h]h)}(h-**Command:** `ethtool --show-pse `h](h)}(h **Command:**h]hCommand:}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh }(hj hhhNhNubj)}(h `ethtool --show-pse `h]hethtool --show-pse }(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jhj ubeh}(h]h ]h"]h$]h&]uh1hhhhKhj ubah}(h]h ]h"]h$]h&]uh1hhj hhhhhNubh)}(hX0**Expected Output Examples**: 1. **PSE Not Supported**: If no PSE is attached or the interface does not support PSE, the following output is expected: .. code-block:: bash netlink error: No PSE is attached netlink error: Operation not supported 2. **PoDL (Single-Pair Ethernet)**: When PoDL is implemented, you might see the following attributes: .. code-block:: bash PSE attributes for eth1: PoDL PSE Admin State: enabled PoDL PSE Power Detection Status: delivering power 3. **PoE (Clause 33 PSE)**: For standard PoE, the output may look like this: .. code-block:: bash PSE attributes for eth1: Clause 33 PSE Admin State: enabled Clause 33 PSE Power Detection Status: delivering power Clause 33 PSE Available Power Limit: 18000 h](h)}(h**Expected Output Examples**:h](h)}(h**Expected Output Examples**h]hExpected Output Examples}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh:}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhj ubh)}(hhh](h)}(h**PSE Not Supported**: If no PSE is attached or the interface does not support PSE, the following output is expected: .. code-block:: bash netlink error: No PSE is attached netlink error: Operation not supported h](h)}(h**PSE Not Supported**:h](h)}(h**PSE Not Supported**h]hPSE Not Supported}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh:}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhj ubh)}(h^If no PSE is attached or the interface does not support PSE, the following output is expected:h]h^If no PSE is attached or the interface does not support PSE, the following output is expected:}(hj% hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhj ubj))}(hHnetlink error: No PSE is attached netlink error: Operation not supportedh]hHnetlink error: No PSE is attached netlink error: Operation not supported}hj3 sbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhKhj ubeh}(h]h ]h"]h$]h&]uh1hhj ubh)}(h**PoDL (Single-Pair Ethernet)**: When PoDL is implemented, you might see the following attributes: .. code-block:: bash PSE attributes for eth1: PoDL PSE Admin State: enabled PoDL PSE Power Detection Status: delivering power h](h)}(h **PoDL (Single-Pair Ethernet)**:h](h)}(h**PoDL (Single-Pair Ethernet)**h]hPoDL (Single-Pair Ethernet)}(hjQ hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjM ubh:}(hjM hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhjI ubh)}(hAWhen PoDL is implemented, you might see the following attributes:h]hAWhen PoDL is implemented, you might see the following attributes:}(hji hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhKhjI ubj))}(hhPSE attributes for eth1: PoDL PSE Admin State: enabled PoDL PSE Power Detection Status: delivering powerh]hhPSE attributes for eth1: PoDL PSE Admin State: enabled PoDL PSE Power Detection Status: delivering power}hjw sbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhKhjI ubeh}(h]h ]h"]h$]h&]uh1hhj ubh)}(hX **PoE (Clause 33 PSE)**: For standard PoE, the output may look like this: .. code-block:: bash PSE attributes for eth1: Clause 33 PSE Admin State: enabled Clause 33 PSE Power Detection Status: delivering power Clause 33 PSE Available Power Limit: 18000 h](h)}(h**PoE (Clause 33 PSE)**:h](h)}(h**PoE (Clause 33 PSE)**h]hPoE (Clause 33 PSE)}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh:}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhKhj ubh)}(h0For standard PoE, the output may look like this:h]h0For standard PoE, the output may look like this:}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhj ubj))}(hPSE attributes for eth1: Clause 33 PSE Admin State: enabled Clause 33 PSE Power Detection Status: delivering power Clause 33 PSE Available Power Limit: 18000h]hPSE attributes for eth1: Clause 33 PSE Admin State: enabled Clause 33 PSE Power Detection Status: delivering power Clause 33 PSE Available Power Limit: 18000}hj sbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhj ubeh}(h]h ]h"]h$]h&]uh1hhj ubeh}(h]h ]h"]h$]h&]jEjFjGhjHjIuh1hhj ubeh}(h]h ]h"]h$]h&]uh1hhj hhhNhNubh)}(hX**Adjust Power Limit (if needed)**: - Sometimes, the available power limit may not be sufficient for the link partner. You can increase the power limit as needed. - **Command:** `ethtool --set-pse c33-pse-avail-pw-limit ` Example: .. code-block:: bash ethtool --set-pse eth1 c33-pse-avail-pw-limit 18000 ethtool --show-pse eth1 **Expected Output** after adjusting the power limit: .. code-block:: bash Clause 33 PSE Available Power Limit: 18000 h](h)}(h#**Adjust Power Limit (if needed)**:h](h)}(h"**Adjust Power Limit (if needed)**h]hAdjust Power Limit (if needed)}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh:}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM hj ubjA)}(hhh](h)}(h}Sometimes, the available power limit may not be sufficient for the link partner. You can increase the power limit as needed. h]h)}(h|Sometimes, the available power limit may not be sufficient for the link partner. You can increase the power limit as needed.h]h|Sometimes, the available power limit may not be sufficient for the link partner. You can increase the power limit as needed.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM hj ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(hX8**Command:** `ethtool --set-pse c33-pse-avail-pw-limit ` Example: .. code-block:: bash ethtool --set-pse eth1 c33-pse-avail-pw-limit 18000 ethtool --show-pse eth1 **Expected Output** after adjusting the power limit: .. code-block:: bash Clause 33 PSE Available Power Limit: 18000 h](h)}(hK**Command:** `ethtool --set-pse c33-pse-avail-pw-limit `h](h)}(h **Command:**h]hCommand:}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh }(hj hhhNhNubj)}(h>`ethtool --set-pse c33-pse-avail-pw-limit `h]h c33-pse-avail-pw-limit }(hj2 hhhNhNubah}(h]h ]h"]h$]h&]uh1jhj ubeh}(h]h ]h"]h$]h&]uh1hhhhMhj ubh)}(hExample:h]hExample:}(hjF hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhj ubj))}(hKethtool --set-pse eth1 c33-pse-avail-pw-limit 18000 ethtool --show-pse eth1h]hKethtool --set-pse eth1 c33-pse-avail-pw-limit 18000 ethtool --show-pse eth1}hjT sbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhj ubh)}(h4**Expected Output** after adjusting the power limit:h](h)}(h**Expected Output**h]hExpected Output}(hjh hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjd ubh! after adjusting the power limit:}(hjd hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj ubj))}(h*Clause 33 PSE Available Power Limit: 18000h]h*Clause 33 PSE Available Power Limit: 18000}hj sbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhj ubeh}(h]h ]h"]h$]h&]uh1hhj ubeh}(h]h ]h"]h$]h&]jjuh1j@hhhM hj ubeh}(h]h ]h"]h$]h&]uh1hhj hhhNhNubh)}(hXx**Next Steps**: - **PoE or PoDL Not Used**: If **PoE** or **PoDL** is not implemented or used on the system, proceed to the next diagnostic step, as power delivery is not relevant for this setup. - **PoE or PoDL Controlled Externally**: If **PoE** or **PoDL** is used but is not managed by the Linux kernel's **PSE-PD** framework (i.e., it is controlled by proprietary user-space software or external tools), this part is out of scope for this documentation. Please consult vendor-specific documentation or external tools for monitoring and managing power delivery. - **PSE Admin State Disabled**: - If the `PSE Admin State:` is **disabled**, enable it by running one of the following commands: .. code-block:: bash ethtool --set-pse podl-pse-admin-control enable or, for Clause 33 PSE (PoE): ethtool --set-pse c33-pse-admin-control enable - After enabling the PSE Admin State, return to the start of the **Check Power Delivery (PoDL or PoE)** step to recheck the power delivery status. - **Power Not Delivered**: If the `Power Detection Status` shows something other than "delivering power" (e.g., `over current`), troubleshoot the **PSE**. Check for potential issues such as a short circuit in the cable, insufficient power delivery, or a fault in the PSE itself. - **Power Delivered but No Link**: If power is being delivered but no link is established, proceed with further diagnostics by performing **Cable Diagnostics** or reviewing the **Inspect Link Status and PHY Configuration** steps to identify any underlying issues with the physical link or settings. h](h)}(h**Next Steps**:h](h)}(h**Next Steps**h]h Next Steps}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh:}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj ubjA)}(hhh](h)}(h**PoE or PoDL Not Used**: If **PoE** or **PoDL** is not implemented or used on the system, proceed to the next diagnostic step, as power delivery is not relevant for this setup. h]h)}(h**PoE or PoDL Not Used**: If **PoE** or **PoDL** is not implemented or used on the system, proceed to the next diagnostic step, as power delivery is not relevant for this setup.h](h)}(h**PoE or PoDL Not Used**h]hPoE or PoDL Not Used}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh: If }(hj hhhNhNubh)}(h**PoE**h]hPoE}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh or }(hj hhhNhNubh)}(h**PoDL**h]hPoDL}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh is not implemented or used on the system, proceed to the next diagnostic step, as power delivery is not relevant for this setup.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM hj ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(hXp**PoE or PoDL Controlled Externally**: If **PoE** or **PoDL** is used but is not managed by the Linux kernel's **PSE-PD** framework (i.e., it is controlled by proprietary user-space software or external tools), this part is out of scope for this documentation. Please consult vendor-specific documentation or external tools for monitoring and managing power delivery. h]h)}(hXo**PoE or PoDL Controlled Externally**: If **PoE** or **PoDL** is used but is not managed by the Linux kernel's **PSE-PD** framework (i.e., it is controlled by proprietary user-space software or external tools), this part is out of scope for this documentation. Please consult vendor-specific documentation or external tools for monitoring and managing power delivery.h](h)}(h%**PoE or PoDL Controlled Externally**h]h!PoE or PoDL Controlled Externally}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh: If }(hj hhhNhNubh)}(h**PoE**h]hPoE}(hj) hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh or }(hj hhhNhNubh)}(h**PoDL**h]hPoDL}(hj; hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh4 is used but is not managed by the Linux kernel’s }(hj hhhNhNubh)}(h **PSE-PD**h]hPSE-PD}(hjM hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh framework (i.e., it is controlled by proprietary user-space software or external tools), this part is out of scope for this documentation. Please consult vendor-specific documentation or external tools for monitoring and managing power delivery.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM$hj ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(hX**PSE Admin State Disabled**: - If the `PSE Admin State:` is **disabled**, enable it by running one of the following commands: .. code-block:: bash ethtool --set-pse podl-pse-admin-control enable or, for Clause 33 PSE (PoE): ethtool --set-pse c33-pse-admin-control enable - After enabling the PSE Admin State, return to the start of the **Check Power Delivery (PoDL or PoE)** step to recheck the power delivery status. h](h)}(h**PSE Admin State Disabled**:h](h)}(h**PSE Admin State Disabled**h]hPSE Admin State Disabled}(hjs hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjo ubh:}(hjo hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM*hjk ubjA)}(hhh](h)}(hXIf the `PSE Admin State:` is **disabled**, enable it by running one of the following commands: .. code-block:: bash ethtool --set-pse podl-pse-admin-control enable or, for Clause 33 PSE (PoE): ethtool --set-pse c33-pse-admin-control enable h](h)}(h^If the `PSE Admin State:` is **disabled**, enable it by running one of the following commands:h](hIf the }(hj hhhNhNubj)}(h`PSE Admin State:`h]hPSE Admin State:}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1jhj ubh is }(hj hhhNhNubh)}(h **disabled**h]hdisabled}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh5, enable it by running one of the following commands:}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM,hj ubj))}(h9ethtool --set-pse podl-pse-admin-control enableh]h9ethtool --set-pse podl-pse-admin-control enable}hj sbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhM/hj ubh)}(hor, for Clause 33 PSE (PoE):h]hor, for Clause 33 PSE (PoE):}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM3hj ubh block_quote)}(h9ethtool --set-pse c33-pse-admin-control enable h]h)}(h8ethtool --set-pse c33-pse-admin-control enableh]h8ethtool --set-pse c33-pse-admin-control enable}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM5hj ubah}(h]h ]h"]h$]h&]uh1j hhhM5hj ubeh}(h]h ]h"]h$]h&]uh1hhj ubh)}(hAfter enabling the PSE Admin State, return to the start of the **Check Power Delivery (PoDL or PoE)** step to recheck the power delivery status. h]h)}(hAfter enabling the PSE Admin State, return to the start of the **Check Power Delivery (PoDL or PoE)** step to recheck the power delivery status.h](h?After enabling the PSE Admin State, return to the start of the }(hj hhhNhNubh)}(h&**Check Power Delivery (PoDL or PoE)**h]h"Check Power Delivery (PoDL or PoE)}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh+ step to recheck the power delivery status.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM7hj ubah}(h]h ]h"]h$]h&]uh1hhj ubeh}(h]h ]h"]h$]h&]jjuh1j@hhhM,hjk ubeh}(h]h ]h"]h$]h&]uh1hhj ubh)}(hX**Power Not Delivered**: If the `Power Detection Status` shows something other than "delivering power" (e.g., `over current`), troubleshoot the **PSE**. Check for potential issues such as a short circuit in the cable, insufficient power delivery, or a fault in the PSE itself. h]h)}(hX**Power Not Delivered**: If the `Power Detection Status` shows something other than "delivering power" (e.g., `over current`), troubleshoot the **PSE**. Check for potential issues such as a short circuit in the cable, insufficient power delivery, or a fault in the PSE itself.h](h)}(h**Power Not Delivered**h]hPower Not Delivered}(hj@ hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj< ubh : If the }(hj< hhhNhNubj)}(h`Power Detection Status`h]hPower Detection Status}(hjR hhhNhNubah}(h]h ]h"]h$]h&]uh1jhj< ubh: shows something other than “delivering power” (e.g., }(hj< hhhNhNubj)}(h`over current`h]h over current}(hjd hhhNhNubah}(h]h ]h"]h$]h&]uh1jhj< ubh), troubleshoot the }(hj< hhhNhNubh)}(h**PSE**h]hPSE}(hjv hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj< ubh}. Check for potential issues such as a short circuit in the cable, insufficient power delivery, or a fault in the PSE itself.}(hj< hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM:hj8 ubah}(h]h ]h"]h$]h&]uh1hhj ubh)}(hX)**Power Delivered but No Link**: If power is being delivered but no link is established, proceed with further diagnostics by performing **Cable Diagnostics** or reviewing the **Inspect Link Status and PHY Configuration** steps to identify any underlying issues with the physical link or settings. h]h)}(hX(**Power Delivered but No Link**: If power is being delivered but no link is established, proceed with further diagnostics by performing **Cable Diagnostics** or reviewing the **Inspect Link Status and PHY Configuration** steps to identify any underlying issues with the physical link or settings.h](h)}(h**Power Delivered but No Link**h]hPower Delivered but No Link}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubhi: If power is being delivered but no link is established, proceed with further diagnostics by performing }(hj hhhNhNubh)}(h**Cable Diagnostics**h]hCable Diagnostics}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh or reviewing the }(hj hhhNhNubh)}(h-**Inspect Link Status and PHY Configuration**h]h)Inspect Link Status and PHY Configuration}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubhL steps to identify any underlying issues with the physical link or settings.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM?hj ubah}(h]h ]h"]h$]h&]uh1hhj ubeh}(h]h ]h"]h$]h&]jjuh1j@hhhM hj ubeh}(h]h ]h"]h$]h&]uh1hhj hhhNhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhKhj hhubeh}(h] check-power-delivery-podl-or-poeah ]h"]"check power delivery (podl or poe)ah$]h&]uh1hhjRhhhhhKubh)9}(hhh](h)}(hCable Diagnosticsh]hCable Diagnostics}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj hhhhhMFubh)}(hXJUse `ethtool` to test for physical layer issues such as cable faults. The test results can vary depending on the cable's condition, the technology in use, and the state of the link partner. The results from the cable test will help in diagnosing issues like open circuits, shorts, impedance mismatches, and noise-related problems.h](hUse }(hj hhhNhNubj)}(h `ethtool`h]hethtool}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhj ubhX? to test for physical layer issues such as cable faults. The test results can vary depending on the cable’s condition, the technology in use, and the state of the link partner. The results from the cable test will help in diagnosing issues like open circuits, shorts, impedance mismatches, and noise-related problems.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMHhj hhubjA)}(hhh]h)}(h0**Command:** `ethtool --cable-test ` h]h)}(h/**Command:** `ethtool --cable-test `h](h)}(h **Command:**h]hCommand:}(hj4hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj0ubh }(hj0hhhNhNubj)}(h"`ethtool --cable-test `h]h ethtool --cable-test }(hjFhhhNhNubah}(h]h ]h"]h$]h&]uh1jhj0ubeh}(h]h ]h"]h$]h&]uh1hhhhMNhj,ubah}(h]h ]h"]h$]h&]uh1hhj)hhhhhNubah}(h]h ]h"]h$]h&]jjuh1j@hhhMNhj hhubh)}(hkThe following are the typical outputs for **Single-Pair Ethernet (SPE)** and **Multi-Pair Ethernet (MPE)**:h](h*The following are the typical outputs for }(hjfhhhNhNubh)}(h**Single-Pair Ethernet (SPE)**h]hSingle-Pair Ethernet (SPE)}(hjnhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjfubh and }(hjfhhhNhNubh)}(h**Multi-Pair Ethernet (MPE)**h]hMulti-Pair Ethernet (MPE)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjfubh:}(hjfhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMPhj hhubjA)}(hhh](h)}(hX**For Single-Pair Ethernet (SPE)**: - **Expected Output (SPE)**: .. code-block:: bash Cable test completed for device eth1. Pair A, fault length: 25.00m Pair A code Open Circuit This indicates an open circuit or cable fault at the reported distance, but results can be influenced by the link partner's state. Refer to the **"Troubleshooting Based on Cable Test Results"** section for further interpretation of these results. h](h)}(h@**For Single-Pair Ethernet (SPE)**: - **Expected Output (SPE)**:h](h)}(h"**For Single-Pair Ethernet (SPE)**h]hFor Single-Pair Ethernet (SPE)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh: - }(hjhhhNhNubh)}(h**Expected Output (SPE)**h]hExpected Output (SPE)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMShjubj))}(h[Cable test completed for device eth1. Pair A, fault length: 25.00m Pair A code Open Circuith]h[Cable test completed for device eth1. Pair A, fault length: 25.00m Pair A code Open Circuit}hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMVhjubh)}(hThis indicates an open circuit or cable fault at the reported distance, but results can be influenced by the link partner's state. Refer to the **"Troubleshooting Based on Cable Test Results"** section for further interpretation of these results.h](hThis indicates an open circuit or cable fault at the reported distance, but results can be influenced by the link partner’s state. Refer to the }(hjhhhNhNubh)}(h1**"Troubleshooting Based on Cable Test Results"**h]h1“Troubleshooting Based on Cable Test Results”}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh5 section for further interpretation of these results.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM\hjubeh}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(hX**For Multi-Pair Ethernet (MPE)**: - **Expected Output (MPE)**: .. code-block:: bash Cable test completed for device eth0. Pair A code OK Pair B code OK Pair C code Open Circuit Here, Pair C is reported as having an open circuit, while Pairs A and B are functioning correctly. However, if autonegotiation is in use on Pairs A and B, the cable test may be disrupted. Refer to the **"Troubleshooting Based on Cable Test Results"** section for a detailed explanation of these issues and how to resolve them. h](h)}(h?**For Multi-Pair Ethernet (MPE)**: - **Expected Output (MPE)**:h](h)}(h!**For Multi-Pair Ethernet (MPE)**h]hFor Multi-Pair Ethernet (MPE)}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh: - }(hjhhhNhNubh)}(h**Expected Output (MPE)**h]hExpected Output (MPE)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMahjubj))}(h\Cable test completed for device eth0. Pair A code OK Pair B code OK Pair C code Open Circuith]h\Cable test completed for device eth0. Pair A code OK Pair B code OK Pair C code Open Circuit}hj5sbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMdhjubh)}(hXFHere, Pair C is reported as having an open circuit, while Pairs A and B are functioning correctly. However, if autonegotiation is in use on Pairs A and B, the cable test may be disrupted. Refer to the **"Troubleshooting Based on Cable Test Results"** section for a detailed explanation of these issues and how to resolve them.h](hHere, Pair C is reported as having an open circuit, while Pairs A and B are functioning correctly. However, if autonegotiation is in use on Pairs A and B, the cable test may be disrupted. Refer to the }(hjEhhhNhNubh)}(h1**"Troubleshooting Based on Cable Test Results"**h]h1“Troubleshooting Based on Cable Test Results”}(hjMhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjEubhL section for a detailed explanation of these issues and how to resolve them.}(hjEhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMkhjubeh}(h]h ]h"]h$]h&]uh1hhjhhhhhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMShj hhubh)}(hFor detailed descriptions of the different possible cable test results, please refer to the **"Troubleshooting Based on Cable Test Results"** section.h](h\For detailed descriptions of the different possible cable test results, please refer to the }(hjqhhhNhNubh)}(h1**"Troubleshooting Based on Cable Test Results"**h]h1“Troubleshooting Based on Cable Test Results”}(hjyhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjqubh section.}(hjqhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMqhj hhubh)}(hhh](h)}(h+Troubleshooting Based on Cable Test Resultsh]h+Troubleshooting Based on Cable Test Results}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhMuubh)}(hX~After running the cable test, the results can help identify specific issues in the physical connection. However, it is important to note that **cable testing results heavily depend on the capabilities and characteristics of both the local hardware and the link partner**. The accuracy and reliability of the results can vary significantly between different hardware implementations.h](hAfter running the cable test, the results can help identify specific issues in the physical connection. However, it is important to note that }(hjhhhNhNubh)}(h**cable testing results heavily depend on the capabilities and characteristics of both the local hardware and the link partner**h]h|cable testing results heavily depend on the capabilities and characteristics of both the local hardware and the link partner}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhp. The accuracy and reliability of the results can vary significantly between different hardware implementations.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMwhjhhubh)}(hIn some cases, this can introduce **blind spots** in the current cable testing implementation, where certain results may not accurately reflect the actual physical state of the cable. For example:h](h"In some cases, this can introduce }(hjhhhNhNubh)}(h**blind spots**h]h blind spots}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh in the current cable testing implementation, where certain results may not accurately reflect the actual physical state of the cable. For example:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM}hjhhubjA)}(hhh](h)}(hAn **Open Circuit** result might not only indicate a damaged or disconnected cable but also occur if the cable is properly attached to a powered-down link partner. h]h)}(hAn **Open Circuit** result might not only indicate a damaged or disconnected cable but also occur if the cable is properly attached to a powered-down link partner.h](hAn }(hjhhhNhNubh)}(h**Open Circuit**h]h Open Circuit}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh result might not only indicate a damaged or disconnected cable but also occur if the cable is properly attached to a powered-down link partner.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(hSome PHYs may report a **Short within Pair** if the link partner is in **forced slave mode**, even though there is no actual short in the cable. h]h)}(hSome PHYs may report a **Short within Pair** if the link partner is in **forced slave mode**, even though there is no actual short in the cable.h](hSome PHYs may report a }(hjhhhNhNubh)}(h**Short within Pair**h]hShort within Pair}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh if the link partner is in }(hjhhhNhNubh)}(h**forced slave mode**h]hforced slave mode}(hj-hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh4, even though there is no actual short in the cable.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhjhhubh)}(hXTo help users interpret the results more effectively, it could be beneficial to extend the **kernel UAPI** (User API) to provide additional context or **possible variants** of issues based on the hardware’s characteristics. Since these quirks are often hardware-specific, the **kernel driver** would be an ideal source of such information. By providing flags or hints related to potential false positives for each test result, users would have a better understanding of what to verify and where to investigate further.h](h[To help users interpret the results more effectively, it could be beneficial to extend the }(hjQhhhNhNubh)}(h**kernel UAPI**h]h kernel UAPI}(hjYhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjQubh- (User API) to provide additional context or }(hjQhhhNhNubh)}(h**possible variants**h]hpossible variants}(hjkhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjQubhj of issues based on the hardware’s characteristics. Since these quirks are often hardware-specific, the }(hjQhhhNhNubh)}(h**kernel driver**h]h kernel driver}(hj}hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjQubh would be an ideal source of such information. By providing flags or hints related to potential false positives for each test result, users would have a better understanding of what to verify and where to investigate further.}(hjQhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjhhubh)}(hUntil such improvements are made, users should be aware of these limitations and manually verify cable issues as needed. Physical inspections may help resolve uncertainties related to false positive results.h]hUntil such improvements are made, users should be aware of these limitations and manually verify cable issues as needed. Physical inspections may help resolve uncertainties related to false positive results.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjhhubh)}(h(The results can be one of the following:h]h(The results can be one of the following:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjhhubjA)}(hhh](h)}(hX**OK**: - The cable is functioning correctly, and no issues were detected. - **Next Steps**: If you are still experiencing issues, it might be related to higher-layer problems, such as duplex mismatches or speed negotiation, which are not physical-layer issues. - **Special Case for `BaseT1` (1000/100/10BaseT1)**: In `BaseT1` systems, an "OK" result typically also means that the link is up and likely in **slave mode**, since cable tests usually only pass in this mode. For some **10BaseT1L** PHYs, an "OK" result may occur even if the cable is too long for the PHY's configured range (for example, when the range is configured for short-distance mode). h](h)}(h**OK**:h](h)}(h**OK**h]hOK}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh](h)}(hAThe cable is functioning correctly, and no issues were detected. h]h)}(h@The cable is functioning correctly, and no issues were detected.h]h@The cable is functioning correctly, and no issues were detected.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(h**Next Steps**: If you are still experiencing issues, it might be related to higher-layer problems, such as duplex mismatches or speed negotiation, which are not physical-layer issues. h]h)}(h**Next Steps**: If you are still experiencing issues, it might be related to higher-layer problems, such as duplex mismatches or speed negotiation, which are not physical-layer issues.h](h)}(h**Next Steps**h]h Next Steps}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh: If you are still experiencing issues, it might be related to higher-layer problems, such as duplex mismatches or speed negotiation, which are not physical-layer issues.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(hX**Special Case for `BaseT1` (1000/100/10BaseT1)**: In `BaseT1` systems, an "OK" result typically also means that the link is up and likely in **slave mode**, since cable tests usually only pass in this mode. For some **10BaseT1L** PHYs, an "OK" result may occur even if the cable is too long for the PHY's configured range (for example, when the range is configured for short-distance mode). h]h)}(hX**Special Case for `BaseT1` (1000/100/10BaseT1)**: In `BaseT1` systems, an "OK" result typically also means that the link is up and likely in **slave mode**, since cable tests usually only pass in this mode. For some **10BaseT1L** PHYs, an "OK" result may occur even if the cable is too long for the PHY's configured range (for example, when the range is configured for short-distance mode).h](h)}(h1**Special Case for `BaseT1` (1000/100/10BaseT1)**h]h-Special Case for `BaseT1` (1000/100/10BaseT1)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh: In }(hjhhhNhNubj)}(h`BaseT1`h]hBaseT1}(hj/hhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubhT systems, an “OK” result typically also means that the link is up and likely in }(hjhhhNhNubh)}(h**slave mode**h]h slave mode}(hjAhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh=, since cable tests usually only pass in this mode. For some }(hjhhhNhNubh)}(h **10BaseT1L**h]h 10BaseT1L}(hjShhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh PHYs, an “OK” result may occur even if the cable is too long for the PHY’s configured range (for example, when the range is configured for short-distance mode).}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hX**Open Circuit**: - An **Open Circuit** result typically indicates that the cable is damaged or disconnected at the reported fault length. Consider these possibilities: - If the link partner is in **admin down** state or powered off, you might still get an "Open Circuit" result even if the cable is functional. - **Next Steps**: Inspect the cable at the fault length for visible damage or loose connections. Verify the link partner is powered on and in the correct mode. h](h)}(h**Open Circuit**:h](h)}(h**Open Circuit**h]h Open Circuit}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj}ubjA)}(hhh]h)}(hXAn **Open Circuit** result typically indicates that the cable is damaged or disconnected at the reported fault length. Consider these possibilities: - If the link partner is in **admin down** state or powered off, you might still get an "Open Circuit" result even if the cable is functional. - **Next Steps**: Inspect the cable at the fault length for visible damage or loose connections. Verify the link partner is powered on and in the correct mode. h](h)}(hAn **Open Circuit** result typically indicates that the cable is damaged or disconnected at the reported fault length. Consider these possibilities:h](hAn }(hjhhhNhNubh)}(h**Open Circuit**h]h Open Circuit}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh result typically indicates that the cable is damaged or disconnected at the reported fault length. Consider these possibilities:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh](h)}(hIf the link partner is in **admin down** state or powered off, you might still get an "Open Circuit" result even if the cable is functional. h]h)}(hIf the link partner is in **admin down** state or powered off, you might still get an "Open Circuit" result even if the cable is functional.h](hIf the link partner is in }(hjhhhNhNubh)}(h**admin down**h]h admin down}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhh state or powered off, you might still get an “Open Circuit” result even if the cable is functional.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(h**Next Steps**: Inspect the cable at the fault length for visible damage or loose connections. Verify the link partner is powered on and in the correct mode. h]h)}(h**Next Steps**: Inspect the cable at the fault length for visible damage or loose connections. Verify the link partner is powered on and in the correct mode.h](h)}(h**Next Steps**h]h Next Steps}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh: Inspect the cable at the fault length for visible damage or loose connections. Verify the link partner is powered on and in the correct mode.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhj}ubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hX!**Short within Pair**: - A **Short within Pair** indicates an unintended connection within the same pair of wires, typically caused by physical damage to the cable. - **Next Steps**: Replace or repair the cable and check for any physical damage or improperly crimped connectors. h](h)}(h**Short within Pair**:h](h)}(h**Short within Pair**h]hShort within Pair}(hj7hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj3ubh:}(hj3hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj/ubjA)}(hhh]h)}(hXA **Short within Pair** indicates an unintended connection within the same pair of wires, typically caused by physical damage to the cable. - **Next Steps**: Replace or repair the cable and check for any physical damage or improperly crimped connectors. h](h)}(hA **Short within Pair** indicates an unintended connection within the same pair of wires, typically caused by physical damage to the cable.h](hA }(hjVhhhNhNubh)}(h**Short within Pair**h]hShort within Pair}(hj^hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjVubht indicates an unintended connection within the same pair of wires, typically caused by physical damage to the cable.}(hjVhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjRubjA)}(hhh]h)}(hp**Next Steps**: Replace or repair the cable and check for any physical damage or improperly crimped connectors. h]h)}(ho**Next Steps**: Replace or repair the cable and check for any physical damage or improperly crimped connectors.h](h)}(h**Next Steps**h]h Next Steps}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhj}ubha: Replace or repair the cable and check for any physical damage or improperly crimped connectors.}(hj}hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjyubah}(h]h ]h"]h$]h&]uh1hhjvubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhjRubeh}(h]h ]h"]h$]h&]uh1hhjOubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhj/ubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hX***Short to Another Pair**: - A **Short to Another Pair** means the wires from different pairs are shorted, which could occur due to physical damage or incorrect wiring. - **Next Steps**: Replace or repair the damaged cable. Inspect the cable for incorrect terminations or pinched wiring. h](h)}(h**Short to Another Pair**:h](h)}(h**Short to Another Pair**h]hShort to Another Pair}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh]h)}(hXA **Short to Another Pair** means the wires from different pairs are shorted, which could occur due to physical damage or incorrect wiring. - **Next Steps**: Replace or repair the damaged cable. Inspect the cable for incorrect terminations or pinched wiring. h](h)}(hA **Short to Another Pair** means the wires from different pairs are shorted, which could occur due to physical damage or incorrect wiring.h](hA }(hjhhhNhNubh)}(h**Short to Another Pair**h]hShort to Another Pair}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhp means the wires from different pairs are shorted, which could occur due to physical damage or incorrect wiring.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh]h)}(hu**Next Steps**: Replace or repair the damaged cable. Inspect the cable for incorrect terminations or pinched wiring. h]h)}(ht**Next Steps**: Replace or repair the damaged cable. Inspect the cable for incorrect terminations or pinched wiring.h](h)}(h**Next Steps**h]h Next Steps}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhf: Replace or repair the damaged cable. Inspect the cable for incorrect terminations or pinched wiring.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hX**Impedance Mismatch**: - **Impedance Mismatch** indicates a reflection caused by an impedance discontinuity in the cable. This can happen when a part of the cable has abnormal impedance (e.g., when different cable types are spliced together or when there is a defect in the cable). - **Next Steps**: Check the cable quality and ensure consistent impedance throughout its length. Replace any sections of the cable that do not meet specifications. h](h)}(h**Impedance Mismatch**:h](h)}(h**Impedance Mismatch**h]hImpedance Mismatch}(hjGhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjCubh:}(hjChhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj?ubjA)}(hhh]h)}(hX**Impedance Mismatch** indicates a reflection caused by an impedance discontinuity in the cable. This can happen when a part of the cable has abnormal impedance (e.g., when different cable types are spliced together or when there is a defect in the cable). - **Next Steps**: Check the cable quality and ensure consistent impedance throughout its length. Replace any sections of the cable that do not meet specifications. h](h)}(hX**Impedance Mismatch** indicates a reflection caused by an impedance discontinuity in the cable. This can happen when a part of the cable has abnormal impedance (e.g., when different cable types are spliced together or when there is a defect in the cable).h](h)}(h**Impedance Mismatch**h]hImpedance Mismatch}(hjjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjfubh indicates a reflection caused by an impedance discontinuity in the cable. This can happen when a part of the cable has abnormal impedance (e.g., when different cable types are spliced together or when there is a defect in the cable).}(hjfhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjbubjA)}(hhh]h)}(h**Next Steps**: Check the cable quality and ensure consistent impedance throughout its length. Replace any sections of the cable that do not meet specifications. h]h)}(h**Next Steps**: Check the cable quality and ensure consistent impedance throughout its length. Replace any sections of the cable that do not meet specifications.h](h)}(h**Next Steps**h]h Next Steps}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh: Check the cable quality and ensure consistent impedance throughout its length. Replace any sections of the cable that do not meet specifications.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhjbubeh}(h]h ]h"]h$]h&]uh1hhj_ubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhj?ubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hX**Noise**: - **Noise** means that the Time Domain Reflectometry (TDR) test could not complete due to excessive noise on the cable, which can be caused by interference from electromagnetic sources. - **Next Steps**: Identify and eliminate sources of electromagnetic interference (EMI) near the cable. Consider using shielded cables or rerouting the cable away from noise sources. h](h)}(h **Noise**:h](h)}(h **Noise**h]hNoise}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh]h)}(hXs**Noise** means that the Time Domain Reflectometry (TDR) test could not complete due to excessive noise on the cable, which can be caused by interference from electromagnetic sources. - **Next Steps**: Identify and eliminate sources of electromagnetic interference (EMI) near the cable. Consider using shielded cables or rerouting the cable away from noise sources. h](h)}(h**Noise** means that the Time Domain Reflectometry (TDR) test could not complete due to excessive noise on the cable, which can be caused by interference from electromagnetic sources.h](h)}(h **Noise**h]hNoise}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh means that the Time Domain Reflectometry (TDR) test could not complete due to excessive noise on the cable, which can be caused by interference from electromagnetic sources.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh]h)}(h**Next Steps**: Identify and eliminate sources of electromagnetic interference (EMI) near the cable. Consider using shielded cables or rerouting the cable away from noise sources. h]h)}(h**Next Steps**: Identify and eliminate sources of electromagnetic interference (EMI) near the cable. Consider using shielded cables or rerouting the cable away from noise sources.h](h)}(h**Next Steps**h]h Next Steps}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhj ubh: Identify and eliminate sources of electromagnetic interference (EMI) near the cable. Consider using shielded cables or rerouting the cable away from noise sources.}(hj hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj ubah}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hX**Resolution Not Possible**: - **Resolution Not Possible** means that the TDR test could not detect the issue due to the resolution limitations of the test or because the fault is beyond the distance that the test can measure. - **Next Steps**: Inspect the cable manually if possible, or use alternative diagnostic tools that can handle greater distances or higher resolution. h](h)}(h**Resolution Not Possible**:h](h)}(h**Resolution Not Possible**h]hResolution Not Possible}(hjOhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjKubh:}(hjKhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjGubjA)}(hhh]h)}(hX]**Resolution Not Possible** means that the TDR test could not detect the issue due to the resolution limitations of the test or because the fault is beyond the distance that the test can measure. - **Next Steps**: Inspect the cable manually if possible, or use alternative diagnostic tools that can handle greater distances or higher resolution. h](h)}(h**Resolution Not Possible** means that the TDR test could not detect the issue due to the resolution limitations of the test or because the fault is beyond the distance that the test can measure.h](h)}(h**Resolution Not Possible**h]hResolution Not Possible}(hjrhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjnubh means that the TDR test could not detect the issue due to the resolution limitations of the test or because the fault is beyond the distance that the test can measure.}(hjnhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjjubjA)}(hhh]h)}(h**Next Steps**: Inspect the cable manually if possible, or use alternative diagnostic tools that can handle greater distances or higher resolution. h]h)}(h**Next Steps**: Inspect the cable manually if possible, or use alternative diagnostic tools that can handle greater distances or higher resolution.h](h)}(h**Next Steps**h]h Next Steps}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh: Inspect the cable manually if possible, or use alternative diagnostic tools that can handle greater distances or higher resolution.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhjjubeh}(h]h ]h"]h$]h&]uh1hhjgubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhjGubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hX(**Unknown**: - An **Unknown** result may occur when the test cannot classify the fault or when a specific issue is outside the scope of the tool's detection capabilities. - **Next Steps**: Re-run the test, verify the link partner's state, and inspect the cable manually if necessary. h](h)}(h **Unknown**:h](h)}(h **Unknown**h]hUnknown}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh]h)}(hXAn **Unknown** result may occur when the test cannot classify the fault or when a specific issue is outside the scope of the tool's detection capabilities. - **Next Steps**: Re-run the test, verify the link partner's state, and inspect the cable manually if necessary. h](h)}(hAn **Unknown** result may occur when the test cannot classify the fault or when a specific issue is outside the scope of the tool's detection capabilities.h](hAn }(hjhhhNhNubh)}(h **Unknown**h]hUnknown}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh result may occur when the test cannot classify the fault or when a specific issue is outside the scope of the tool’s detection capabilities.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh]h)}(ho**Next Steps**: Re-run the test, verify the link partner's state, and inspect the cable manually if necessary. h]h)}(hn**Next Steps**: Re-run the test, verify the link partner's state, and inspect the cable manually if necessary.h](h)}(h**Next Steps**h]h Next Steps}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhb: Re-run the test, verify the link partner’s state, and inspect the cable manually if necessary.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhjhhubeh}(h]+troubleshooting-based-on-cable-test-resultsah ]h"]+troubleshooting based on cable test resultsah$]h&]uh1hhj hhhhhMuubeh}(h]cable-diagnosticsah ]h"]cable diagnosticsah$]h&]uh1hhjRhhhhhMFubh)}(hhh](h)}(h%Verify Link Partner PHY Configurationh]h%Verify Link Partner PHY Configuration}(hjlhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjihhhhhMubh)}(hIf the cable test passes but the link is still not functioning correctly, it’s essential to verify the configuration of the link partner’s PHY. Mismatches in speed, duplex settings, or master-slave roles can cause connection issues.h]hIf the cable test passes but the link is still not functioning correctly, it’s essential to verify the configuration of the link partner’s PHY. Mismatches in speed, duplex settings, or master-slave roles can cause connection issues.}(hjzhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjihhubh)}(hhh](h)}(hAutonegotiation Mismatchh]hAutonegotiation Mismatch}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhMubjA)}(hhh](h)}(hIf both link partners support autonegotiation, ensure that autonegotiation is enabled on both sides and that all supported link modes are advertised. A mismatch can lead to connectivity problems or sub optimal performance. h]h)}(hIf both link partners support autonegotiation, ensure that autonegotiation is enabled on both sides and that all supported link modes are advertised. A mismatch can lead to connectivity problems or sub optimal performance.h]hIf both link partners support autonegotiation, ensure that autonegotiation is enabled on both sides and that all supported link modes are advertised. A mismatch can lead to connectivity problems or sub optimal performance.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(h**Quick Fix:** Reset autonegotiation to the default settings, which will advertise all default link modes: .. code-block:: bash ethtool -s autoneg on h](h)}(hj**Quick Fix:** Reset autonegotiation to the default settings, which will advertise all default link modes:h](h)}(h**Quick Fix:**h]h Quick Fix:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh\ Reset autonegotiation to the default settings, which will advertise all default link modes:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubj))}(h!ethtool -s autoneg onh]h!ethtool -s autoneg on}hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(h:**Command to check configuration:** `ethtool ` h]h)}(h9**Command to check configuration:** `ethtool `h](h)}(h#**Command to check configuration:**h]hCommand to check configuration:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh }(hjhhhNhNubj)}(h`ethtool `h]hethtool }(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(hX**Expected Output:** Ensure that both sides advertise compatible link modes. If autonegotiation is off, verify that both link partners are configured for the same speed and duplex. The following example shows a case where the local PHY advertises fewer link modes than it supports. This will reduce the number of overlapping link modes with the link partner. In the worst case, there will be no common link modes, and the link will not be created: .. code-block:: bash Settings for eth0: Supported link modes: 1000baseT/Full, 100baseT/Full Advertised link modes: 1000baseT/Full Speed: 1000Mb/s Duplex: Full Auto-negotiation: on h](h)}(h**Expected Output:** Ensure that both sides advertise compatible link modes. If autonegotiation is off, verify that both link partners are configured for the same speed and duplex.h](h)}(h**Expected Output:**h]hExpected Output:}(hj&hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj"ubh Ensure that both sides advertise compatible link modes. If autonegotiation is off, verify that both link partners are configured for the same speed and duplex.}(hj"hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubh)}(hX The following example shows a case where the local PHY advertises fewer link modes than it supports. This will reduce the number of overlapping link modes with the link partner. In the worst case, there will be no common link modes, and the link will not be created:h]hX The following example shows a case where the local PHY advertises fewer link modes than it supports. This will reduce the number of overlapping link modes with the link partner. In the worst case, there will be no common link modes, and the link will not be created:}(hj>hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjubj))}(hSettings for eth0: Supported link modes: 1000baseT/Full, 100baseT/Full Advertised link modes: 1000baseT/Full Speed: 1000Mb/s Duplex: Full Auto-negotiation: onh]hSettings for eth0: Supported link modes: 1000baseT/Full, 100baseT/Full Advertised link modes: 1000baseT/Full Speed: 1000Mb/s Duplex: Full Auto-negotiation: on}hjLsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhjhhubeh}(h]autonegotiation-mismatchah ]h"]autonegotiation mismatchah$]h&]uh1hhjihhhhhMubh)}(hhh](h)}(hICombined Mode Mismatch (Autonegotiation on One Side, Forced on the Other)h]hICombined Mode Mismatch (Autonegotiation on One Side, Forced on the Other)}(hjshhhNhNubah}(h]h ]h"]h$]h&]uh1hhjphhhhhMubjA)}(hhh](h)}(hXOne possible issue occurs when one side is using **autonegotiation** (as in most modern systems), and the other side is set to a **forced link mode** (e.g., older hardware with single-speed hubs). In such cases, modern PHYs will attempt to detect the forced mode on the other side. If the link is established, you may notice: - **No or empty "Link partner advertised link modes"**. - **"Link partner advertised auto-negotiation:"** will be **"no"** or not present. h](h)}(hXEOne possible issue occurs when one side is using **autonegotiation** (as in most modern systems), and the other side is set to a **forced link mode** (e.g., older hardware with single-speed hubs). In such cases, modern PHYs will attempt to detect the forced mode on the other side. If the link is established, you may notice:h](h1One possible issue occurs when one side is using }(hjhhhNhNubh)}(h**autonegotiation**h]hautonegotiation}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh= (as in most modern systems), and the other side is set to a }(hjhhhNhNubh)}(h**forced link mode**h]hforced link mode}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh (e.g., older hardware with single-speed hubs). In such cases, modern PHYs will attempt to detect the forced mode on the other side. If the link is established, you may notice:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh](h)}(h6**No or empty "Link partner advertised link modes"**. h]h)}(h5**No or empty "Link partner advertised link modes"**.h](h)}(h4**No or empty "Link partner advertised link modes"**h]h4No or empty “Link partner advertised link modes”}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(hQ**"Link partner advertised auto-negotiation:"** will be **"no"** or not present. h]h)}(hP**"Link partner advertised auto-negotiation:"** will be **"no"** or not present.h](h)}(h/**"Link partner advertised auto-negotiation:"**h]h/“Link partner advertised auto-negotiation:”}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh will be }(hjhhhNhNubh)}(h**"no"**h]h“no”}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh or not present.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hXKThis type of detection does not always work reliably: - Typically, the modern PHY will default to **Half Duplex**, even if the link partner is actually configured for **Full Duplex**. - Some PHYs may not work reliably if the link partner switches from one forced mode to another. In this case, only a down/up cycle may help. h](h)}(h5This type of detection does not always work reliably:h]h5This type of detection does not always work reliably:}(hj+hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhj'ubjA)}(hhh](h)}(hTypically, the modern PHY will default to **Half Duplex**, even if the link partner is actually configured for **Full Duplex**. h]h)}(hTypically, the modern PHY will default to **Half Duplex**, even if the link partner is actually configured for **Full Duplex**.h](h*Typically, the modern PHY will default to }(hj@hhhNhNubh)}(h**Half Duplex**h]h Half Duplex}(hjHhhhNhNubah}(h]h ]h"]h$]h&]uh1hhj@ubh6, even if the link partner is actually configured for }(hj@hhhNhNubh)}(h**Full Duplex**h]h Full Duplex}(hjZhhhNhNubah}(h]h ]h"]h$]h&]uh1hhj@ubh.}(hj@hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM!hj<ubah}(h]h ]h"]h$]h&]uh1hhj9ubh)}(hSome PHYs may not work reliably if the link partner switches from one forced mode to another. In this case, only a down/up cycle may help. h]h)}(hSome PHYs may not work reliably if the link partner switches from one forced mode to another. In this case, only a down/up cycle may help.h]hSome PHYs may not work reliably if the link partner switches from one forced mode to another. In this case, only a down/up cycle may help.}(hj|hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM$hjxubah}(h]h ]h"]h$]h&]uh1hhj9ubeh}(h]h ]h"]h$]h&]jjuh1j@hhhM!hj'ubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(h**Next Steps**: Set both sides to the same fixed speed and duplex mode to avoid potential detection issues. .. code-block:: bash ethtool -s speed 1000 duplex full autoneg off h](h)}(hk**Next Steps**: Set both sides to the same fixed speed and duplex mode to avoid potential detection issues.h](h)}(h**Next Steps**h]h Next Steps}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh]: Set both sides to the same fixed speed and duplex mode to avoid potential detection issues.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM'hjubj))}(h9ethtool -s speed 1000 duplex full autoneg offh]h9ethtool -s speed 1000 duplex full autoneg off}hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhM*hjubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhjphhubeh}(h]Fcombined-mode-mismatch-autonegotiation-on-one-side-forced-on-the-otherah ]h"]Icombined mode mismatch (autonegotiation on one side, forced on the other)ah$]h&]uh1hhjihhhhhMubh)}(hhh](h)}(h6Master/Slave Role Mismatch (BaseT1 and 1000BaseT PHYs)h]h6Master/Slave Role Mismatch (BaseT1 and 1000BaseT PHYs)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhM/ubjA)}(hhh](h)}(hXVIn **BaseT1** systems (e.g., 1000BaseT1, 100BaseT1), link establishment requires that one device is configured as **master** and the other as **slave**. A mismatch in this master-slave configuration can prevent the link from being established. However, **1000BaseT** also supports configurable master/slave roles and can face similar issues. h]h)}(hXUIn **BaseT1** systems (e.g., 1000BaseT1, 100BaseT1), link establishment requires that one device is configured as **master** and the other as **slave**. A mismatch in this master-slave configuration can prevent the link from being established. However, **1000BaseT** also supports configurable master/slave roles and can face similar issues.h](hIn }(hjhhhNhNubh)}(h **BaseT1**h]hBaseT1}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhe systems (e.g., 1000BaseT1, 100BaseT1), link establishment requires that one device is configured as }(hjhhhNhNubh)}(h **master**h]hmaster}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh and the other as }(hjhhhNhNubh)}(h **slave**h]hslave}(hj$hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhf. A mismatch in this master-slave configuration can prevent the link from being established. However, }(hjhhhNhNubh)}(h **1000BaseT**h]h 1000BaseT}(hj6hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhK also supports configurable master/slave roles and can face similar issues.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM1hjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(hXH**Role Preference in 1000BaseT**: The **1000BaseT** specification allows link partners to negotiate master-slave roles or role preferences during autonegotiation. Some PHYs have hardware limitations or bugs that prevent them from functioning properly in certain roles. In such cases, drivers may force these PHYs into a specific role (e.g., **forced master** or **forced slave**) or try a weaker option by setting preferences. If both link partners have the same issue and are forced into the same mode (e.g., both forced into master mode), they will not be able to establish a link. h]h)}(hXG**Role Preference in 1000BaseT**: The **1000BaseT** specification allows link partners to negotiate master-slave roles or role preferences during autonegotiation. Some PHYs have hardware limitations or bugs that prevent them from functioning properly in certain roles. In such cases, drivers may force these PHYs into a specific role (e.g., **forced master** or **forced slave**) or try a weaker option by setting preferences. If both link partners have the same issue and are forced into the same mode (e.g., both forced into master mode), they will not be able to establish a link.h](h)}(h **Role Preference in 1000BaseT**h]hRole Preference in 1000BaseT}(hj\hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjXubh: The }(hjXhhhNhNubh)}(h **1000BaseT**h]h 1000BaseT}(hjnhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjXubhX" specification allows link partners to negotiate master-slave roles or role preferences during autonegotiation. Some PHYs have hardware limitations or bugs that prevent them from functioning properly in certain roles. In such cases, drivers may force these PHYs into a specific role (e.g., }(hjXhhhNhNubh)}(h**forced master**h]h forced master}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjXubh or }(hjXhhhNhNubh)}(h**forced slave**h]h forced slave}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjXubh) or try a weaker option by setting preferences. If both link partners have the same issue and are forced into the same mode (e.g., both forced into master mode), they will not be able to establish a link.}(hjXhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM7hjTubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(hX**Next Steps**: Ensure that one side is configured as **master** and the other as **slave** to avoid this issue, particularly when hardware limitations are involved, or try the weaker **preferred** option instead of **forced**. Check for any driver-related restrictions or forced modes. h]h)}(hX**Next Steps**: Ensure that one side is configured as **master** and the other as **slave** to avoid this issue, particularly when hardware limitations are involved, or try the weaker **preferred** option instead of **forced**. Check for any driver-related restrictions or forced modes.h](h)}(h**Next Steps**h]h Next Steps}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh(: Ensure that one side is configured as }(hjhhhNhNubh)}(h **master**h]hmaster}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh and the other as }(hjhhhNhNubh)}(h **slave**h]hslave}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh] to avoid this issue, particularly when hardware limitations are involved, or try the weaker }(hjhhhNhNubh)}(h **preferred**h]h preferred}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh option instead of }(hjhhhNhNubh)}(h **forced**h]hforced}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh<. Check for any driver-related restrictions or forced modes.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM@hjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(h**Command to force master/slave mode**: .. code-block:: bash ethtool -s master-slave forced-master or: .. code-block:: bash ethtool -s master-slave forced-master speed 1000 duplex full autoneg off h](h)}(h'**Command to force master/slave mode**:h](h)}(h&**Command to force master/slave mode**h]h"Command to force master/slave mode}(hj&hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj"ubh:}(hj"hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMEhjubj))}(h1ethtool -s master-slave forced-masterh]h1ethtool -s master-slave forced-master}hj>sbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMGhjubh)}(hor:h]hor:}(hjNhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMKhjubj))}(hTethtool -s master-slave forced-master speed 1000 duplex full autoneg offh]hTethtool -s master-slave forced-master speed 1000 duplex full autoneg off}hj\sbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMMhjubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(h**Check the current master/slave status**: .. code-block:: bash ethtool Example Output: .. code-block:: bash master-slave cfg: forced-master master-slave status: master h](h)}(h***Check the current master/slave status**:h](h)}(h)**Check the current master/slave status**h]h%Check the current master/slave status}(hjzhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjvubh:}(hjvhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMRhjrubj))}(hethtool h]hethtool }hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMThjrubh)}(hExample Output:h]hExample Output:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMXhjrubj))}(h;master-slave cfg: forced-master master-slave status: masterh]h;master-slave cfg: forced-master master-slave status: master}hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMZhjrubeh}(h]h ]h"]h$]h&]uh1hhjhhhNhNubh)}(hXb**Hardware Bugs and Driver Forcing**: If a known hardware issue forces the PHY into a specific mode, it’s essential to check the driver source code or hardware documentation for details. Ensure that the roles are compatible across both link partners, and if both PHYs are forced into the same mode, adjust one side accordingly to resolve the mismatch. h]h)}(hXa**Hardware Bugs and Driver Forcing**: If a known hardware issue forces the PHY into a specific mode, it’s essential to check the driver source code or hardware documentation for details. Ensure that the roles are compatible across both link partners, and if both PHYs are forced into the same mode, adjust one side accordingly to resolve the mismatch.h](h)}(h$**Hardware Bugs and Driver Forcing**h]h Hardware Bugs and Driver Forcing}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhX=: If a known hardware issue forces the PHY into a specific mode, it’s essential to check the driver source code or hardware documentation for details. Ensure that the roles are compatible across both link partners, and if both PHYs are forced into the same mode, adjust one side accordingly to resolve the mismatch.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhM_hjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhM1hjhhubeh}(h]4master-slave-role-mismatch-baset1-and-1000baset-physah ]h"]6master/slave role mismatch (baset1 and 1000baset phys)ah$]h&]uh1hhjihhhhhM/ubeh}(h]%verify-link-partner-phy-configurationah ]h"]%verify link partner phy configurationah$]h&]uh1hhjRhhhhhMubh)}(hhh](h)}(h#Monitor Link Resets and Speed Dropsh]h#Monitor Link Resets and Speed Drops}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhMfubh)}(hXIf the link is unstable, showing frequent resets or speed drops, this may indicate issues with the cable, PHY configuration, or environmental factors. While there is still no completely unified way in Linux to directly monitor downshift events or link speed changes via user space tools, both the Linux kernel logs and `ethtool` can provide valuable insights, especially if the driver supports reporting such events.h](hX?If the link is unstable, showing frequent resets or speed drops, this may indicate issues with the cable, PHY configuration, or environmental factors. While there is still no completely unified way in Linux to directly monitor downshift events or link speed changes via user space tools, both the Linux kernel logs and }(hjhhhNhNubj)}(h `ethtool`h]hethtool}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubhX can provide valuable insights, especially if the driver supports reporting such events.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhhjhhubjA)}(hhh](h)}(hX **Monitor Kernel Logs for Link Resets and Speed Drops**: - The Linux kernel will print link status changes, including downshift events, in the system logs. These messages typically include speed changes, duplex mode, and downshifted link speed (if the driver supports it). - **Command to monitor kernel logs in real-time:** .. code-block:: bash dmesg -w | grep "Link is Up\|Link is Down" - Example Output (if a downshift occurs): .. code-block:: bash eth0: Link is Up - 100Mbps/Full (downshifted) - flow control rx/tx eth0: Link is Down This indicates that the link has been established but has downshifted from a higher speed. - **Note**: Not all drivers or PHYs support downshift reporting, so you may not see this information for all devices. h](h)}(h8**Monitor Kernel Logs for Link Resets and Speed Drops**:h](h)}(h7**Monitor Kernel Logs for Link Resets and Speed Drops**h]h3Monitor Kernel Logs for Link Resets and Speed Drops}(hj>hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj:ubh:}(hj:hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMohj6ubjA)}(hhh](h)}(hThe Linux kernel will print link status changes, including downshift events, in the system logs. These messages typically include speed changes, duplex mode, and downshifted link speed (if the driver supports it). h]h)}(hThe Linux kernel will print link status changes, including downshift events, in the system logs. These messages typically include speed changes, duplex mode, and downshifted link speed (if the driver supports it).h]hThe Linux kernel will print link status changes, including downshift events, in the system logs. These messages typically include speed changes, duplex mode, and downshifted link speed (if the driver supports it).}(hj]hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMqhjYubah}(h]h ]h"]h$]h&]uh1hhjVubh)}(hu**Command to monitor kernel logs in real-time:** .. code-block:: bash dmesg -w | grep "Link is Up\|Link is Down" h](h)}(h0**Command to monitor kernel logs in real-time:**h]h)}(hjwh]h,Command to monitor kernel logs in real-time:}(hjyhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjuubah}(h]h ]h"]h$]h&]uh1hhhhMuhjqubj))}(h*dmesg -w | grep "Link is Up\|Link is Down"h]h*dmesg -w | grep "Link is Up\|Link is Down"}hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMwhjqubeh}(h]h ]h"]h$]h&]uh1hhjVubh)}(hExample Output (if a downshift occurs): .. code-block:: bash eth0: Link is Up - 100Mbps/Full (downshifted) - flow control rx/tx eth0: Link is Down This indicates that the link has been established but has downshifted from a higher speed. h](h)}(h'Example Output (if a downshift occurs):h]h'Example Output (if a downshift occurs):}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM{hjubj))}(hUeth0: Link is Up - 100Mbps/Full (downshifted) - flow control rx/tx eth0: Link is Downh]hUeth0: Link is Up - 100Mbps/Full (downshifted) - flow control rx/tx eth0: Link is Down}hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhM}hjubh)}(hZThis indicates that the link has been established but has downshifted from a higher speed.h]hZThis indicates that the link has been established but has downshifted from a higher speed.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjVubh)}(ht**Note**: Not all drivers or PHYs support downshift reporting, so you may not see this information for all devices. h]h)}(hs**Note**: Not all drivers or PHYs support downshift reporting, so you may not see this information for all devices.h](h)}(h**Note**h]hNote}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhk: Not all drivers or PHYs support downshift reporting, so you may not see this information for all devices.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjVubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMqhj6ubeh}(h]h ]h"]h$]h&]uh1hhj3hhhNhNubh)}(hX**Monitor Link Down Events Using `ethtool`**: - Starting with the latest kernel and `ethtool` versions, you can track **Link Down Events** using the `ethtool -I` command. This will provide counters for link drops, helping to diagnose link instability issues if supported by the driver. - **Command to monitor link down events:** .. code-block:: bash ethtool -I - Example Output (if supported): .. code-block:: bash PSE attributes for eth1: Link Down Events: 5 This indicates that the link has dropped 5 times. Frequent link down events may indicate cable or environmental issues that require further investigation. h](h)}(h-**Monitor Link Down Events Using `ethtool`**:h](h)}(h,**Monitor Link Down Events Using `ethtool`**h]h(Monitor Link Down Events Using `ethtool`}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj ubjA)}(hhh](h)}(hStarting with the latest kernel and `ethtool` versions, you can track **Link Down Events** using the `ethtool -I` command. This will provide counters for link drops, helping to diagnose link instability issues if supported by the driver. h]h)}(hStarting with the latest kernel and `ethtool` versions, you can track **Link Down Events** using the `ethtool -I` command. This will provide counters for link drops, helping to diagnose link instability issues if supported by the driver.h](h$Starting with the latest kernel and }(hj1hhhNhNubj)}(h `ethtool`h]hethtool}(hj9hhhNhNubah}(h]h ]h"]h$]h&]uh1jhj1ubh versions, you can track }(hj1hhhNhNubh)}(h**Link Down Events**h]hLink Down Events}(hjKhhhNhNubah}(h]h ]h"]h$]h&]uh1hhj1ubh using the }(hj1hhhNhNubj)}(h `ethtool -I`h]h ethtool -I}(hj]hhhNhNubah}(h]h ]h"]h$]h&]uh1jhj1ubh| command. This will provide counters for link drops, helping to diagnose link instability issues if supported by the driver.c}(hj1hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj-ubah}(h]h ]h"]h$]h&]uh1hhj*ubh)}(hY**Command to monitor link down events:** .. code-block:: bash ethtool -I h](h)}(h(**Command to monitor link down events:**h]h)}(hjh]h$Command to monitor link down events:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubah}(h]h ]h"]h$]h&]uh1hhhhMhj{ubj))}(hethtool -I h]hethtool -I }hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhj{ubeh}(h]h ]h"]h$]h&]uh1hhj*ubh)}(hXExample Output (if supported): .. code-block:: bash PSE attributes for eth1: Link Down Events: 5 This indicates that the link has dropped 5 times. Frequent link down events may indicate cable or environmental issues that require further investigation. h](h)}(hExample Output (if supported):h]hExample Output (if supported):}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjubj))}(h,PSE attributes for eth1: Link Down Events: 5h]h,PSE attributes for eth1: Link Down Events: 5}hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhjubh)}(hThis indicates that the link has dropped 5 times. Frequent link down events may indicate cable or environmental issues that require further investigation.h]hThis indicates that the link has dropped 5 times. Frequent link down events may indicate cable or environmental issues that require further investigation.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjubeh}(h]h ]h"]h$]h&]uh1hhj*ubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhj ubeh}(h]h ]h"]h$]h&]uh1hhj3hhhNhNubh)}(hX**Check Link Status and Speed**: - Even though downshift counts or events are not easily tracked, you can still use `ethtool` to manually check the current link speed and status. - **Command:** `ethtool ` - **Expected Output:** .. code-block:: bash Speed: 1000Mb/s Duplex: Full Auto-negotiation: on Link detected: yes Any inconsistencies in the expected speed or duplex setting could indicate an issue. h](h)}(h **Check Link Status and Speed**:h](h)}(h**Check Link Status and Speed**h]hCheck Link Status and Speed}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh](h)}(hEven though downshift counts or events are not easily tracked, you can still use `ethtool` to manually check the current link speed and status. h]h)}(hEven though downshift counts or events are not easily tracked, you can still use `ethtool` to manually check the current link speed and status.h](hQEven though downshift counts or events are not easily tracked, you can still use }(hjhhhNhNubj)}(h `ethtool`h]hethtool}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubh5 to manually check the current link speed and status.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(h#**Command:** `ethtool ` h]h)}(h"**Command:** `ethtool `h](h)}(h **Command:**h]hCommand:}(hjChhhNhNubah}(h]h ]h"]h$]h&]uh1hhj?ubh }(hj?hhhNhNubj)}(h`ethtool `h]hethtool }(hjUhhhNhNubah}(h]h ]h"]h$]h&]uh1jhj?ubeh}(h]h ]h"]h$]h&]uh1hhhhMhj;ubah}(h]h ]h"]h$]h&]uh1hhjubh)}(h**Expected Output:** .. code-block:: bash Speed: 1000Mb/s Duplex: Full Auto-negotiation: on Link detected: yes Any inconsistencies in the expected speed or duplex setting could indicate an issue. h](h)}(h**Expected Output:**h]h)}(hjuh]hExpected Output:}(hjwhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjsubah}(h]h ]h"]h$]h&]uh1hhhhMhjoubj))}(hDSpeed: 1000Mb/s Duplex: Full Auto-negotiation: on Link detected: yesh]hDSpeed: 1000Mb/s Duplex: Full Auto-negotiation: on Link detected: yes}hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhjoubh)}(hTAny inconsistencies in the expected speed or duplex setting could indicate an issue.h]hTAny inconsistencies in the expected speed or duplex setting could indicate an issue.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjoubeh}(h]h ]h"]h$]h&]uh1hhjubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhj3hhhNhNubh)}(hX**Disable Energy-Efficient Ethernet (EEE) for Diagnostics**: - **EEE** (Energy-Efficient Ethernet) can be a source of link instability due to transitions in and out of low-power states. For diagnostic purposes, it may be useful to **temporarily** disable EEE to determine if it is contributing to link instability. This is **not a generic recommendation** for disabling power management. - **Next Steps**: Disable EEE and monitor if the link becomes stable. If disabling EEE resolves the issue, report the bug so that the driver can be fixed. - **Command:** .. code-block:: bash ethtool --set-eee eee off - **Important**: If disabling EEE resolves the instability, the issue should be reported to the maintainers as a bug, and the driver should be corrected to handle EEE properly without causing instability. Disabling EEE permanently should not be seen as a solution. h](h)}(h<**Disable Energy-Efficient Ethernet (EEE) for Diagnostics**:h](h)}(h;**Disable Energy-Efficient Ethernet (EEE) for Diagnostics**h]h7Disable Energy-Efficient Ethernet (EEE) for Diagnostics}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh](h)}(hXE**EEE** (Energy-Efficient Ethernet) can be a source of link instability due to transitions in and out of low-power states. For diagnostic purposes, it may be useful to **temporarily** disable EEE to determine if it is contributing to link instability. This is **not a generic recommendation** for disabling power management. h]h)}(hXD**EEE** (Energy-Efficient Ethernet) can be a source of link instability due to transitions in and out of low-power states. For diagnostic purposes, it may be useful to **temporarily** disable EEE to determine if it is contributing to link instability. This is **not a generic recommendation** for disabling power management.h](h)}(h**EEE**h]hEEE}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh (Energy-Efficient Ethernet) can be a source of link instability due to transitions in and out of low-power states. For diagnostic purposes, it may be useful to }(hjhhhNhNubh)}(h**temporarily**h]h temporarily}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubhM disable EEE to determine if it is contributing to link instability. This is }(hjhhhNhNubh)}(h **not a generic recommendation**h]hnot a generic recommendation}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh for disabling power management.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(h**Next Steps**: Disable EEE and monitor if the link becomes stable. If disabling EEE resolves the issue, report the bug so that the driver can be fixed. h]h)}(h**Next Steps**: Disable EEE and monitor if the link becomes stable. If disabling EEE resolves the issue, report the bug so that the driver can be fixed.h](h)}(h**Next Steps**h]h Next Steps}(hj/hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj+ubh: Disable EEE and monitor if the link becomes stable. If disabling EEE resolves the issue, report the bug so that the driver can be fixed.}(hj+hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj'ubah}(h]h ]h"]h$]h&]uh1hhjubh)}(hL**Command:** .. code-block:: bash ethtool --set-eee eee off h](h)}(h **Command:**h]h)}(hjSh]hCommand:}(hjUhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjQubah}(h]h ]h"]h$]h&]uh1hhhhMhjMubj))}(h%ethtool --set-eee eee offh]h%ethtool --set-eee eee off}hjhsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhjMubeh}(h]h ]h"]h$]h&]uh1hhjubh)}(hX**Important**: If disabling EEE resolves the instability, the issue should be reported to the maintainers as a bug, and the driver should be corrected to handle EEE properly without causing instability. Disabling EEE permanently should not be seen as a solution. h]h)}(hX**Important**: If disabling EEE resolves the instability, the issue should be reported to the maintainers as a bug, and the driver should be corrected to handle EEE properly without causing instability. Disabling EEE permanently should not be seen as a solution.h](h)}(h **Important**h]h Important}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh: If disabling EEE resolves the instability, the issue should be reported to the maintainers as a bug, and the driver should be corrected to handle EEE properly without causing instability. Disabling EEE permanently should not be seen as a solution.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj~ubah}(h]h ]h"]h$]h&]uh1hhjubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhj3hhhNhNubh)}(hX**Monitor Error Counters**: - Use `ethtool -S --all-groups` to retrieve standardized interface statistics if the driver supports the unified interface: - **Command:** `ethtool -S --all-groups` - **Example Output (if supported)**: .. code-block:: bash phydev-RxFrames: 100391 phydev-RxErrors: 0 phydev-TxFrames: 9 phydev-TxErrors: 0 - If the unified interface is not supported, use `ethtool -S ` to retrieve MAC and PHY counters. Note that non-standardized PHY counter names vary by driver and must be interpreted accordingly: - **Command:** `ethtool -S ` - **Example Output (if supported)**: .. code-block:: bash rx_crc_errors: 123 tx_errors: 45 rx_frame_errors: 78 - **Note**: If no meaningful error counters are available or if counters are not supported, you may need to rely on physical inspections (e.g., cable condition) or kernel log messages (e.g., link up/down events) to further diagnose the issue. - **Compare Counters**: - Compare the egress and ingress frame counts reported by the PHY and MAC. - A small difference may occur due to sampling rate differences between the MAC and PHY drivers, or if the PHY and MAC are not always fully synchronized in their UP or DOWN states. - Significant discrepancies indicate potential issues in the data path between the MAC and PHY. h](h)}(h**Monitor Error Counters**:h](h)}(h**Monitor Error Counters**h]hMonitor Error Counters}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubjA)}(hhh](h)}(hUse `ethtool -S --all-groups` to retrieve standardized interface statistics if the driver supports the unified interface: h]h)}(hUse `ethtool -S --all-groups` to retrieve standardized interface statistics if the driver supports the unified interface:h](hUse }(hjhhhNhNubj)}(h%`ethtool -S --all-groups`h]h#ethtool -S --all-groups}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubh\ to retrieve standardized interface statistics if the driver supports the unified interface:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(h3**Command:** `ethtool -S --all-groups` h]h)}(h2**Command:** `ethtool -S --all-groups`h](h)}(h **Command:**h]hCommand:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh }(hjhhhNhNubj)}(h%`ethtool -S --all-groups`h]h#ethtool -S --all-groups}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(h**Example Output (if supported)**: .. code-block:: bash phydev-RxFrames: 100391 phydev-RxErrors: 0 phydev-TxFrames: 9 phydev-TxErrors: 0 h](h)}(h"**Example Output (if supported)**:h](h)}(h!**Example Output (if supported)**h]hExample Output (if supported)}(hj9hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj5ubh:}(hj5hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj1ubj))}(hPphydev-RxFrames: 100391 phydev-RxErrors: 0 phydev-TxFrames: 9 phydev-TxErrors: 0h]hPphydev-RxFrames: 100391 phydev-RxErrors: 0 phydev-TxFrames: 9 phydev-TxErrors: 0}hjQsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhj1ubeh}(h]h ]h"]h$]h&]uh1hhjubh)}(hIf the unified interface is not supported, use `ethtool -S ` to retrieve MAC and PHY counters. Note that non-standardized PHY counter names vary by driver and must be interpreted accordingly: h]h)}(hIf the unified interface is not supported, use `ethtool -S ` to retrieve MAC and PHY counters. Note that non-standardized PHY counter names vary by driver and must be interpreted accordingly:h](h/If the unified interface is not supported, use }(hjkhhhNhNubj)}(h`ethtool -S `h]hethtool -S }(hjshhhNhNubah}(h]h ]h"]h$]h&]uh1jhjkubh to retrieve MAC and PHY counters. Note that non-standardized PHY counter names vary by driver and must be interpreted accordingly:}(hjkhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjgubah}(h]h ]h"]h$]h&]uh1hhjubh)}(h&**Command:** `ethtool -S ` h]h)}(h%**Command:** `ethtool -S `h](h)}(h **Command:**h]hCommand:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh }(hjhhhNhNubj)}(h`ethtool -S `h]hethtool -S }(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1jhjubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(hu**Example Output (if supported)**: .. code-block:: bash rx_crc_errors: 123 tx_errors: 45 rx_frame_errors: 78 h](h)}(h"**Example Output (if supported)**:h](h)}(h!**Example Output (if supported)**h]hExample Output (if supported)}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh:}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubj))}(h4rx_crc_errors: 123 tx_errors: 45 rx_frame_errors: 78h]h4rx_crc_errors: 123 tx_errors: 45 rx_frame_errors: 78}hjsbah}(h]h ]h"]h$]h&]hhj8j9bashj;}uh1j(hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhjubh)}(h**Note**: If no meaningful error counters are available or if counters are not supported, you may need to rely on physical inspections (e.g., cable condition) or kernel log messages (e.g., link up/down events) to further diagnose the issue. h]h)}(h**Note**: If no meaningful error counters are available or if counters are not supported, you may need to rely on physical inspections (e.g., cable condition) or kernel log messages (e.g., link up/down events) to further diagnose the issue.h](h)}(h**Note**h]hNote}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjubh: If no meaningful error counters are available or if counters are not supported, you may need to rely on physical inspections (e.g., cable condition) or kernel log messages (e.g., link up/down events) to further diagnose the issue.}(hjhhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjubh)}(hX**Compare Counters**: - Compare the egress and ingress frame counts reported by the PHY and MAC. - A small difference may occur due to sampling rate differences between the MAC and PHY drivers, or if the PHY and MAC are not always fully synchronized in their UP or DOWN states. - Significant discrepancies indicate potential issues in the data path between the MAC and PHY. h](h)}(h**Compare Counters**:h](h)}(h**Compare Counters**h]hCompare Counters}(hj)hhhNhNubah}(h]h ]h"]h$]h&]uh1hhj%ubh:}(hj%hhhNhNubeh}(h]h ]h"]h$]h&]uh1hhhhMhj!ubjA)}(hhh](h)}(hICompare the egress and ingress frame counts reported by the PHY and MAC. h]h)}(hHCompare the egress and ingress frame counts reported by the PHY and MAC.h]hHCompare the egress and ingress frame counts reported by the PHY and MAC.}(hjHhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjDubah}(h]h ]h"]h$]h&]uh1hhjAubh)}(hA small difference may occur due to sampling rate differences between the MAC and PHY drivers, or if the PHY and MAC are not always fully synchronized in their UP or DOWN states. h]h)}(hA small difference may occur due to sampling rate differences between the MAC and PHY drivers, or if the PHY and MAC are not always fully synchronized in their UP or DOWN states.h]hA small difference may occur due to sampling rate differences between the MAC and PHY drivers, or if the PHY and MAC are not always fully synchronized in their UP or DOWN states.}(hj`hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhj\ubah}(h]h ]h"]h$]h&]uh1hhjAubh)}(h^Significant discrepancies indicate potential issues in the data path between the MAC and PHY. h]h)}(h]Significant discrepancies indicate potential issues in the data path between the MAC and PHY.h]h]Significant discrepancies indicate potential issues in the data path between the MAC and PHY.}(hjxhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjtubah}(h]h ]h"]h$]h&]uh1hhjAubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhj!ubeh}(h]h ]h"]h$]h&]uh1hhjubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMhjubeh}(h]h ]h"]h$]h&]uh1hhj3hhhNhNubeh}(h]h ]h"]h$]h&]jjuh1j@hhhMohjhhubeh}(h]#monitor-link-resets-and-speed-dropsah ]h"]#monitor link resets and speed dropsah$]h&]uh1hhjRhhhhhMfubh)}(hhh](h)}(hWhen All Else Fails...h]hWhen All Else Fails...}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhjhhhhhMubh)}(hSo you've checked the cables, monitored the logs, disabled EEE, and still... nothing? Don’t worry, you’re not alone. Sometimes, Ethernet gremlins just don’t want to cooperate.h]hSo you’ve checked the cables, monitored the logs, disabled EEE, and still... nothing? Don’t worry, you’re not alone. Sometimes, Ethernet gremlins just don’t want to cooperate.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjhhubh)}(hkBut before you throw in the towel (or the Ethernet cable), take a deep breath. It’s always possible that:h]hkBut before you throw in the towel (or the Ethernet cable), take a deep breath. It’s always possible that:}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjhhubh)}(hhh](h)}(h1Your PHY has a unique, undocumented personality. h]h)}(h0Your PHY has a unique, undocumented personality.h]h0Your PHY has a unique, undocumented personality.}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(hpThe problem is lying dormant, waiting for just the right moment to magically resolve itself (hey, it happens!). h]h)}(hoThe problem is lying dormant, waiting for just the right moment to magically resolve itself (hey, it happens!).h]hoThe problem is lying dormant, waiting for just the right moment to magically resolve itself (hey, it happens!).}(hjhhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubh)}(hNOr, it could be that the ultimate solution simply hasn’t been invented yet. h]h)}(hMOr, it could be that the ultimate solution simply hasn’t been invented yet.h]hMOr, it could be that the ultimate solution simply hasn’t been invented yet.}(hj hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhj ubah}(h]h ]h"]h$]h&]uh1hhjhhhhhNubeh}(h]h ]h"]h$]h&]jEjFjGhjHjIuh1hhjhhhhhMubh)}(hX2If none of the above bring you comfort, there’s one final step: contribute! If you've uncovered new or unusual issues, or have creative diagnostic methods, feel free to share your findings and extend this documentation. Together, we can hunt down every elusive network issue - one twisted pair at a time.h]hX4If none of the above bring you comfort, there’s one final step: contribute! If you’ve uncovered new or unusual issues, or have creative diagnostic methods, feel free to share your findings and extend this documentation. Together, we can hunt down every elusive network issue - one twisted pair at a time.}(hj0 hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhM hjhhubh)}(hsRemember: sometimes the solution is just a reboot away, but if not, it’s time to dig deeper - or report that bug!h]hsRemember: sometimes the solution is just a reboot away, but if not, it’s time to dig deeper - or report that bug!}(hj> hhhNhNubah}(h]h ]h"]h$]h&]uh1hhhhMhjhhubeh}(h]when-all-else-failsah ]h"]when all else fails...ah$]h&]uh1hhjRhhhhhMubeh}(h]9step-by-step-diagnostic-guide-from-linux-general-ethernetah ]h"];step-by-step diagnostic guide from linux (general ethernet)ah$]h&]uh1hhhhhhhhKubeh}(h]Rdiagnostic-concept-for-investigating-twisted-pair-ethernet-variants-at-osi-layer-1ah ]h"]Rdiagnostic concept for investigating twisted pair ethernet variants at osi layer 1ah$]h&]uh1hhhhhhhhKubeh}(h]h ]h"]h$]h&]sourcehuh1hcurrent_sourceN current_lineNsettingsdocutils.frontendValues)}(hN generatorN datestampN source_linkN source_urlN toc_backlinksentryfootnote_backlinksK sectnum_xformKstrip_commentsNstrip_elements_with_classesN strip_classesN report_levelK halt_levelKexit_status_levelKdebugNwarning_streamN tracebackinput_encoding utf-8-siginput_encoding_error_handlerstrictoutput_encodingutf-8output_encoding_error_handlerj error_encodingutf-8error_encoding_error_handlerbackslashreplace language_codeenrecord_dependenciesNconfigN id_prefixhauto_id_prefixid dump_settingsNdump_internalsNdump_transformsNdump_pseudo_xmlNexpose_internalsNstrict_visitorN_disable_configN_sourceh _destinationN _config_files]7/var/lib/git/docbuild/linux/Documentation/docutils.confafile_insertion_enabled raw_enabledKline_length_limitM'pep_referencesN pep_base_urlhttps://peps.python.org/pep_file_url_templatepep-%04drfc_referencesN rfc_base_url&https://datatracker.ietf.org/doc/html/ tab_widthKtrim_footnote_reference_spacesyntax_highlightlong smart_quotessmartquotes_locales]character_level_inline_markupdoctitle_xform docinfo_xformKsectsubtitle_xform image_loadinglinkembed_stylesheetcloak_email_addressessection_self_linkenvNubreporterNindirect_targets]substitution_defs}substitution_names}refnames}refids}nameids}(ja j^ jOjLjY jV jjjjj j j j jfjcj^j[jjjmjjjjjjjjjQ jN u nametypes}(ja jOjY jjj j jfj^jjmjjjjQ uh}(j^ hjLhjV jRjj/jjj jj j jcj j[jjjijjjjjpjjjjjN ju footnote_refs} citation_refs} autofootnotes]autofootnote_refs]symbol_footnotes]symbol_footnote_refs] footnotes] citations]autofootnote_startKsymbol_footnote_startK id_counter collectionsCounter}Rparse_messages]transform_messages] transformerN include_log] decorationNhhub.