Mobile Ip Nat Traversal - Cisco ASR 5000 Series Administration Manual

▀ Features and Functionality - Optional Enhanced Feature Software
Accurate accounting
Timely notification to mobile node of change in service
The system is capable of supporting both GGSN and Mobile IP functions on a single chassis. For Mobile IP
applications, the system can be configured to provide the function of a Gateway GPRS Support Node/Foreign Agent
(GGSNSN/FA) and/or a Home Agent (HA).
HA and FA components are defined by RFC 2002 in support of Mobile IP. Mobile IP provides a network-layer solution
that allows Mobile Nodes (MNs, i.e. mobile phones, wireless PDAs, and other mobile devices) to receive routed IP
packets from their home network while they are connected to any visitor network using their permanent or home IP
address. Mobile IP allows mobility in a dynamic method that allows nodes to maintain ongoing communications while
changing links as the user traverses the global Internet from various locations outside their home network.
When configured to support HA functionality, the system is capable of supporting following enhanced features:
Mobile IP HA Session Rejection/Redirection: Enables the HA service to either reject new calls or redirect
them to another HA when a destination network connection failure is detected. When network connectivity is
re-established, the HA service begins to accept calls again in the normal manner. This feature provides the
benefit of reducing OpEx through increased operational efficiency and limiting of system downtime.
Mobile IP Registration Revocation: Registration Revocation is a general mechanism whereby the HA
providing Mobile IP or Proxy Mobile IP functionality to a mobile node can notify the GGSN/FA of the
termination of a binding. Mobile IP Registration Revocation can be triggered at the HA by any of the
following:
Important:
Administration Guide and GGSN Administration Guide respectively

Mobile IP NAT Traversal

This functionality enables converged WiFi-cellular data deployments in which the system is used to concentrate and
switch traffic between WiFi hotspots. UDP/IP tunneling enables NAT firewalls in WLAN hotspots to maintain state
information for address translation between NATed public address/UDP ports and addresses that are privately assigned
for the mobile access device by a local DHCP server.
The Mobile IP protocol does not easily accommodate subscriber mobile nodes that are located behind WLAN or WAN-
based NAT devices because it assumes that the addresses of mobile nodes or FA's are globally routable prefixes.
However, the mobile node‟s co-located care of address (CCoA/CoA) is a private address. This presents a problem when
remote hosts try to reach the mobile node via the public advertised addresses. The system provides a solution that
utilizes UDP tunneling subject to subscriber reservation requests. In this application, the HA uses IP UDP tunneling to
reach the mobile subscriber and includes the same private address that was provided in original reservation request in
the encapsulated IP payload packet header.
▄ Cisco ASR 5000 Series Gateway GPRS Support Node Administration Guide
Administrative clearing of calls
Session Manager software task outage resulting in the loss of FA sessions (sessions that could not be
recovered)
Session Idle timer expiry (when configured to send Revocation)
Any other condition under which a binding is terminated due to local policy (duplicate IMSI detected,
duplicate home address requested)
For more information on Mobile IP HA service and FA service configuration, refer HA
GGSN Support in GPRS/UMTS Wireless Data Services
OL-22944-02