Bgp Failover Configuration; Figure 11-3:Bgp Failover Configuration Example - Nortel Alteon OS 42C4911 Application Manual

Alteon OS Application Guide

BGP Failover Configuration

Use the following example to create redundant default gateways for a GbE Switch Module at a
Web Host/ISP site, eliminating the possibility, should one gateway go down, that requests will
be forwarded to an upstream router unknown to the switch.
As shown in
with both ISPs to allow the switch to use their peer routers as default gateways. The ISP peer
routers will then need to announce themselves as default gateways to the GbE Switch Module.
Figure 11-3 BGP Failover Configuration Example
On the GbE Switch Module, one peer router (the secondary one) is configured with a longer
AS path than the other, so that the peer with the shorter AS path will be seen by the switch as
the primary default gateway. ISP 2, the secondary peer, is configured with a metric of "3,"
thereby appearing to the switch to be three router hops away.
182 Chapter 11: Border Gateway Protocol
Figure 11-3, the switch is connected to ISP 1 and ISP 2. The customer negotiates
GbE Switch
GbE Switch
Module
Module
BladeCenter
BladeCenter
Server 1
IP: 200.200.200.10
VIP: 200.200.200.200 VIP: 200.200.200.200
IP: 200.200.200.1
IP: 200.200.200.1
IP: 210.210.210.1
IP: 210.210.210.1
Server 2
IP: 200.200.200.11
42C4911, January 2007