Cisco Systems 78-11741-02 manual IPC-189

Configuring Mobile IP

Mobile IP Configuration Examples

HA Redundancy for Multiple Virtual Networks Using Multiple Physical Networks Example

This section presents two configuration examples:

•The mobile node and home agent are on different subnets.

•The mobile node and home agent are on the same subnet.

Figure 33 shows an example network topology for this configuration type.

Figure 33 Topology Showing HA Redundancy on Virtual Networks Using Multiple Physical Networks

	Active
	HA1
	Virtual
	networks
HSRP		HSRP	Loopback
			interface
Router group		group
address 1	address 2
Internet	Standby		42304
	HA2
Home		Home
network 1		network 2

Foreign

agent

Mobile Node and Home Agent on Different Subnets

HA1 and HA2 share responsibility in providing home agent service for mobile nodes on virtual networks 20.0.0.0, 30.0.0.0, and 40.0.0.0. Both home agents are configured with a global home agent address of 10.0.0.10, which is the address of their loopback interface. This configuration allows home agents to receive registration requests and packets destined to 10.0.0.10.

The loopback address is used as the global HA address instead of the HSRP group addresses 1.0.0.10 and 2.0.0.10 to allow the HAs to continue serving the virtual networks even if either physical network goes down.

Mobile nodes are configured with home agent address 10.0.0.10. When registrations come in, either home agent processes them (depending on routing protocols) and updates the peer home agent. The home agent that receives the registration finds the first HSRP group that is mapped to 10.0.0.10 with a peer in the group and sends the update out that interface. If there is a network problem (for example, the home agent network adapter fails or cable disconnects), HSRP notices the absence of the peer. The home agent does not use that HSRP group and finds another HSRP group to use.

Cisco IOS IP Configuration Guide

IPC-189