Cisco Systems 78-11741-02 manual HA1 Configuration, IPC-181

Configuring Mobile IP

Mobile IP Configuration Examples

Figure 30 Topology Showing HA Redundancy on a Physical Network

Active

HA1

1.0.0.1

Router

HSRP

group

address Standby HA2

Internet 1.0.0.2

Physical

home

network

39274

HA1 is favored to provide home agent service for mobile nodes on physical network e0 because the priority is set to 110, which is above the default of 100. HA1 will preempt any active home agent when it comes up. During preemption, it does not become the active home agent until it retrieves the mobility binding table from the current active home agent or until 100 seconds expire for home agent synchronization.

Note If the standby preempt command is used, the preempt synchronization delay must be set or mobility bindings cannot be retrieved before the home agent preempts to become active.

The standby HSRP group name is SanJoseHA and the HSRP group address is 1.0.0.10. The standby HA uses this HSRP group address to retrieve mobility bindings for mobile nodes on the physical network. Mobile IP is configured to use the SanJoseHA standby group to provide home agent redundancy.

Mobile nodes are configured with HA address 1.0.0.10. When registrations come in, only the active home agent processes them. The active home agent sends a mobility binding update to the standby home agent, which also sets up a tunnel with the same source and destination endpoints. Updates and table retrievals are authenticated using the security associations configured on the home agent for its peer home agent. When packets destined for mobile nodes are received, either of the home agents tunnel them. If HA1 goes down, HA2 becomes active through HSRP and will process packets sent to home agent address 1.0.0.10.

HA1 Configuration

interface ethernet0

ip address 1.0.0.1 255.0.0.0 standby ip 1.0.0.10 standby name SanJoseHA standby preempt delay sync 100 standby priority 110

ip mobile home-agent standby SanJoseHA

ip mobile secure home-agent 1.0.0.2 spi 100 key hex 00112233445566778899001122334455

Cisco IOS IP Configuration Guide

IPC-181