Nortel Networks 8000 - Manual (Page 34)

1 WAN access overview
Nortel Secure Router 8000 Series
Configuration -WAN Access
Interface Command Line
View
Command Prompt
LoopBack interface LoopBack
interface view Run the
interface
loopback 2
command in the
system view.
[Nortel-LoopBack2]
NULL interface NULL interface
view
Run the
interface null 0
command in the
system view.
[Nortel-NULLO]
Tunnel interface Tunnel interface
view
Run the
interface tunnel
0/0/6 command
in the system
view.
[Nortel-Tunnel0/0/6]
ED NOTE
The SR8000 is a centralized device. For the interfaces such as the Mp-group interface, tunnel interface,
and virtual-ethernet interface, the slot number and card number are fixed as 0.
This document describes parameters of the WAN physical interfaces and logical interfaces.
For other functions related to LAN and network layer protocols, refer to other manuals in the
Nortel Secure Router 8000 Series Configuration Guide.
1.1.2 Link layer protocols of WAN
PPP
The link layer provides reliable transmission of data from one site to the other. The link layer
receives packets from the network layer, and then encapsulates packets into frames to deliver
them to the physical layer.
WAN link layer protocols supported by the SR8000 are described as follows.
The Point-to-Point Protocol (PPP) encapsulates an IP datagram over serial links. It supports
the 8-bit asynchronous mode, free of parity check and bit-oriented synchronous link.
PPP includes the Line Control Protocol (LCP) to create, configure, and authenticate the data
links. It also includes the Network Control Protocol (NCP) that is oriented to different
network layer protocols.
The SR8000 also supports the Multi-link Protocol (MP), which binds multiple PPP links
together to provide larger bandwidth.
X.25 and LAPB
X.25 is an interface procedure between the data terminal equipment (DTE) and the data
circuit-terminating equipment (DCE).
X.25 has the following functions:
1-4 Nortel Networks Inc. Issue 5.3 (30 March 2009)