Cabletron Systems 9032578-05 manual Ibgp Configuration Example

Chapter 12: BGP Configuration Guide

The gated.conf file for router SSR1 is as follows:

autonomoussystem 1 ; routerid 10.0.0.1 ; bgp yes {

group type external peeras 2

{

peer 10.0.0.2

;

};

};

The CLI configuration for router SSR2 is as follows:

interface create ip et.1.1 address-netmask 10.0.0.2/16 port et.1.1 ip-router global set autonomous-system 2

ip-router global set router-id 10.0.0.2

bgp create peer-group pg2w1 type external autonomous-system 1 bgp add peer-host 10.0.0.1 group pg2w1

bgp start

The gated.conf file for router SSR2 is as follows:

autonomoussystem 2 ; routerid 10.0.0.2 ; bgp yes {

group type external peeras 1

{

peer 10.0.0.1

;

};

};

IBGP Configuration Example

Connections between BGP speakers within the same AS are referred to as internal links. A peer in the same AS is an internal peer. Internal BGP is commonly abbreviated IBGP; external BGP is EBGP.

An AS that has two or more EBGP peers is referred to as a multihomed AS. A multihomed AS can “transit” traffic between two ASs by advertising to one AS routes that it learned from the other AS. To successfully provide transit services, all EBGP speakers in the transit AS must have a consistent view of all of the routes reachable through their AS.

Multihomed transit ASs can use IBGP between EBGP-speaking routers in the AS to synchronize their routing tables. IBGP requires a full-mesh configuration; all EBGP speaking routers must have an IBGP peering session with every other EBGP speaking router in the AS.

SmartSwitch Router User Reference Manual 135