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Cellular IP

PostPosted: Thu Oct 24, 2013 6:38 am
by Prasanth
Cellular IP: A new Paradigm in Internet Host Mobility

Cellular IP is a new robust protocol that is optimized to support local mobility but efficiently interworks with Mobile IP to provide wide area mobility. Cellular IP shows great benefit in comparison to existing host mobility protocols for environments where mobile hosts migrate frequently. This is very much valid as wireless internet becomes widespread.

CIP can accommodate large no of users by maintaining distributed Paging and Routing caches.Also CIP requires no new packet formats, encapsulations, or address space allocations beyond what is present in IP. Since mobile IP is only optimized for macro level mobility and relatively slow moving hosts this is no longer an optimal solution.

Wireless Access network Model

Access network:: is a group of cells. A network model primarily consists of base stations interconnected by wired links as shown:

Apart from base stations the network can contain node that have no radio devices. They do not communicate with the MHs, but route IP packets with in the access network. E.g. Node E. Wireless access networks are connected to the global internet by routers called Gateways. These acts as both the Home agent and Foreign agent for visiting hosts.

There are 5 key requirements of wireless access networks, that motivate the design of CIP protocol.

Easy Global Migration (Migration should be transparent to the user)

This is achieved by :
- allowing the BS to emit beacon signals to allow for MHs to identify them.
- when MH connects the access network it must inform its HA as required by MIP
- for global reachability, the MH uses a local C/O address, but within the access network its identified by its home IP

Cheap Passive Connectivity


This is the mechanism of keeping track of idle MHs. The idea is to let idle MHs impose a little load on the network
- This also allows max. no users connected to a network and also reduces the network load

Flexible Handoff

The wireless access network should support smooth handoff, mean that when a host changes cell packets should continue to be delivered with little disturbance. This is achieved by temporarily allowing simultaneous transmissions.

Efficient Location Management

Tracking MHs closely requires control messages to be sent after every migration, and to process that becomes very inefficient
On the other hand letting them roam untracked, and searching for them, when there is data to send is inefficient and highly unscalable
So efficient location management scheme is required that maintains loc info of idle MHs with out overloading the network

Simple Memory less Mobile hosts

To allow cheap end-user devices, a wireless access network should assume little complexity in the MHs
Eg: In adhoc mobile there is no concept of BS, so lot of complexity/memory, etc in MHs