ATM is a high-speed networking technology for Local Area Networks and Wide Area Networks. It uses a fixed packet size and is connection oriented, allowing for the negotiation of minimum bandwidth requirements. In order to participate in an ATM network, your Linux box needs an ATM networking card. If you have that, say Y here and to the driver of your ATM card below. Note that you need a set of user-space programs to actually make use of ATM. See the file <file:Documentation/networking/atm.txt> for further details.
Classical IP over ATM for PVCs and SVCs, supporting InARP and ATMARP. If you want to communication with other IP hosts on your ATM network, you will typically either say Y here or to "LAN Emulation (LANE)" below.
Normally, an "ICMP host unreachable" message is sent if a neighbour cannot be reached because there is no VC to it in the kernel's ATMARP table. This may cause problems when ATMARP table entries are briefly removed during revalidation. If you say Y here, packets to such neighbours are silently discarded instead.
LAN Emulation emulates services of existing LANs across an ATM network. Besides operating as a normal ATM end station client, Linux LANE client can also act as an proxy client bridging packets between ELAN and Ethernet segments. You need LANE if you want to try MPOA.
Multi-Protocol Over ATM allows ATM edge devices such as routers, bridges and ATM attached hosts establish direct ATM VCs across subnetwork boundaries. These shortcut connections bypass routers enhancing overall network performance.
ATM PVCs can carry ethernet PDUs according to RFC2684 (formerly 1483) This device will act like an ethernet from the kernels point of view, with the traffic being carried by ATM PVCs (currently 1 PVC/device). This is sometimes used over DSL lines. If in doubt, say N.
This is an experimental mechanism for users who need to terminate a large number of IP-only vcc's. Do not enable this unless you are sure you know what you are doing.