Cisco ASR 5000 Series, Обзор продукта

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HA Overview
Understanding Mobile IP ▀
Cisco ASR 5000 Series Product Overview ▄
OL-22938-02
Understanding 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.
In Mobile IP, the Mobile Node (MN) receives an IP address, either static or dynamic, called the ―home address‖
assigned by its Home Agent (HA). A distinct advantage with Mobile IP is that MNs can hand off between different
radio networks that are served by different PDSNs.
In this scenario, the Network Access Function (such as a PDSN) in the visitor network performs as a Foreign Agent
(FA), establishing a virtual session with the MN's HA. Each time the MN registers with a different PDSN/FA, the FA
assigns the MN a care-of-address. Packets are then encapsulated into IP tunnels and transported between FA, HA, and
the MN.
Session Continuity Support for 3GPP2 and WiMAX Handoffs
HA provides this feature for seamless session mobility for WiMAX subscriber and other access technology subscribers
as well. By implementation of this feature HA can be configured for:
3GPP2 HA Service
3GPP HA Service
WiMAX HA Service
Combination of 3GPP2 and WiMAX HA Services for Dual mode device
The above configurations provide the session continuity capability that enables a dual mode device (a multi radio
device) to continue its active data session as it changes its active network attachment from 3GPP2 to Wimax and vice
versa with no perceived user impacts from a user experience perspective. This capability brings the following benefits:
common billing and customer care
accessing home 3GPP2 service through Wimax network and vice versa
better user experience with seamless session continuity