Cellular IP: A New Approach to Internet Host Mobility Reporter：江俊毅

Outline Cellular IP introduction Routing Protocol Paging Paging & Routing caches Handoff Conclusion

Introduction Mobility overview Macro-mobility Micro-mobility Mobile IP MIPV6 MIPV4 Micro-mobility Cellular IP HAWAII HIP

Cellular IP Cellular IP represents a new mobile host protocol simple, and flexible protocol for highly mobile hosts CIP supports local mobility & efficiently internet works with Mobile IP

Wirelss access networks and mobile IP

Wireless Access network Model Internet with Mobile IP R A C E F G Home agent of MH Gateway D B 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 START ANIMATION - BEACON PACKETS BY BS (MH acquires a c/o address by listening to the advertisement) - REGISTERING THE C/O ADDRESS (The mobile host, with the help of its foreign agent informs its home agent to set up a binding between its Home Address and its c/o Address. *This message is sent on a hop-by-hop basis to the GW along the uplinks. HOME AGENT: Authenticates the binding update messages Updates its binding table Sends acknowledgement back to the GW Beacon signal MH

MOBILE IP CELLULAR IP Packets transmitted by mobile hosts Packets will be first routed to the host's home agent and then tunneled to the gateway Packets transmitted by mobile hosts are first routed to the gateway and from there on to the Internet MOBILE IP The gateway "detunnels'' packets and forwards them toward base stations CELLULAR IP

Cellular IP Paging Idle mobile hosts that receive a packet move from idle to active state, start their active-state-timer and immediately transmit a route-update packet. This ensures that routing cache mappings are established quickly

Mobile host state machine

Efficient Location Management PAGING & ROUTING X PC RC Service Area Mobile Host 1 3 2 4 Two parallel structures of mappings (PC &RC) 1 - idle MH keeps PC upto-date 2 - PC mappings used to find the loc of idle MH 3 - maintains RC mappings until actively connected 4 - routing of data packets to MH 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

Illustration of Paging I don’t have a PC MH B D R A C E F G Internet with Mobile IP GW X X : from C X : from G Paging-update Paging-update packets create mappings in PCs

PCs updated for a moving host No change in PC at A X : from G X : from C B D R A C E F G Internet with Mobile IP GW X X : from F X : from F,G G times out MH

Paging packets are routed to the mobile host by PCs X : from F X : from C B D R A C E F G Internet with Mobile IP GW MH X X

Handoff E B D R A C F G Internet with Mobile IP GW X : from D X : from E X : from C E B D R A C F G Internet with Mobile IP GW X X : from F X : from D, E

Paging & Routing caches

Handoff Cellular IP handoff Hard handoff Semi-soft handoff During the Handoff Latency the downlink packets are lost. Improvement over Hard Handoff

Hard-Handoff 1.MN From Old BS to New BS 2.MN send Route Update Packet to GW 3.BSs are refresh RS 4.GW send data packets to MN

Semi soft-Handoff Improvement over Hard Handoff ; NO packet loss & smooth handoff. Need for buffering at the cross over point :For smooth handoff

Compare Mobile IP & Cellular IP Location management Mobile IP: Care-of-address Cellular IP: paging update packet Routing Mobile IP: registration Cellular IP: routing cache Handoff Mobile IP: encapsulation, triangle routing

Conclusion Cheap passive connectivity using PC and RC Flexible handoff Cellular IP represents a new approach to IP host mobility Cheap passive connectivity using PC and RC Flexible handoff The important issue : Authentication and security

End Thanks~