Mobile Ip - Cisco ASR 5000 series Product Overview

▀ Understanding Simple IP and Mobile IP
Step Description
6 The RADIUS AAA server successfully authenticates the subscriber and returns an Access Accept message to the PDSN.
The Accept message may contain various attributes to be assigned to the MN.
7 The PDSN sends a PPP Authentication Response message to the MN.
8 The MN and the PDSN negotiate the Internet Protocol Control Protocol (IPCP) that results in the MN receiving an IP
address.
9 The PDSN forwards a RADIUS Accounting Start message to the AAA server fully establishing the session allowing the
MN to send/receive data to/from the PDN.
10 Upon completion of the session, the MN sends an LCP Terminate Request message to the PDSN to end the PPP session.
11 The BSC closes the radio link while the PCF closes the R-P session between it and the PDSN. All PDSN resources used to
facilitate the session are reclaimed (IP address, memory, etc.).
12 The PDSN sends accounting stop record to the AAA server, ending the session.

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 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.
Mobile IP Tunneling Methods
Tunneling by itself is a technology that enables one network to send its data via another network's connections.
Tunneling works by encapsulating a network protocol within a packet, carried by the second network. Tunneling is also
called encapsulation. Service providers typically use tunneling for two purposes; first, to transport otherwise un-routable
packets across the IP network and second, to provide data separation for Virtual Private Networking (VPN) services. In
Mobile IP, tunnels are used to transport data packets between the FA and HA.
The system supports the following tunneling protocols, as defined in the IS-835-A specification and the relevant
Request For Comments (RFCs) for Mobile IP:
IP in IP tunnels
▄ Cisco ASR 5000 Series Product Overview
CDMA2000 Wireless Data Services
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