Cisco Cisco IOS Software Release 12.3(11)T

Supports ingress and egress filtering.

Maintains binding information for each registered MS containing an association of Care-of Address 
(CoA) with the home address, NAI, and security keys together with the lifetime of that association.

Receives and processes registration renewal requests within the bounds of the Mobile IP registration 
lifetime timer, either from the MS (through the FA in the Mobile IP case), or from the FA (in the 
Proxy Mobile IP case).

Receives and processes de-registration requests either from the MS (through the FA in the Mobile 
IP case), or from the FA (in the Proxy Mobile IP case).

Maintains a subscriber database that is stored locally or retrieved from an external source.

Sends a binding update to the source PDSN under hand-off conditions when suitably configured.

Supports dynamic HA assignment.

The Home Agent (HA) maintains mobile user registrations and tunnels packets destined for the mobile 
to the PDSN/FA. It supports reverse tunneling, and can securely tunnel packets to the PDSN using IPSec. 
Broadcast packets are not tunneled. Additionally, the HA performs dynamic home address assignment 
for the mobile. Home address assignment can be from address pools configured locally, through either 
DHCP server access, or from the AAA server. 

The Cisco HA supports proxy Mobile IP functionality, and is available on the 7600, 7200, and 6500 
series platforms. A Cisco HA based on the Cisco 7200 series router supports up to 262,000 mobile 
bindings, can process 100 bindings per second, and is RFC 2002, RFC 2003, RFC 2005 and RFC2006 
compliant. 

A Cisco HA based on the Cisco 76 00 series router or Cisco Catalyst 6500 switch, with two MWAM 
cards housing five active HA images and five standby images, would support the above figures 
multiplied by 5. 

For more information on Mobile IP as it relates to Home Agent configuration tasks, please refer to the 
following url:

Basic Mobile IP resource revocation is an IS-835-C initiative that defines the methods by which a 
mobility agent (one that provides Mobile IP services to a mobile node) can notify the other mobility 
agent of the termination of a registration due to administrative reasons or MIP handoff.

This feature is similar to the Cisco MobileIP Bind Update feature. When a mobile changes its point of 
attachment (FA), or needs to terminate the session administratively, the HA sends a registration 
revocation message to the old FA. The old FA tears down the session and sends registration revocation 
acknowledgement message to the HA. In another scenario, if the PDSN/FA needs to terminate the 
session administratively, the FA sends registration revocation message to the HA. The HA deletes the 
binding for the mobile and sends registration revocation acknowledgement to FA. 

An HA configured to support registration revocation in Mobile Ipv4 includes a revocation support 
extension in all MIP RRP for the associated MIP RRQ from the PDSN that contained a valid registration 
revocation extension. A registration for which the HA received a revocation support extension, and 
responded with a subsequent revocation support extension, is considered revocable by the HA.