THE IP MOBILITY APPROACH

발표자 : 이진우

Tables1. Introduction2. Domain Based Micro Mobility Supporting Protocols 2.1 Cellular IP 2.1.1 Network Architecture, Routing and Paging 2.1.2 Handover Mechanisms 2.2 HAWAII 2.2.1 Network Architecture, Routing and Paging 2.2.2 Handover Mechanisms3. Protocol Reflections 3.1 Host Based Routing and Paging 3.2 Path Setup Schemes and Signaling

4. Conclusions

1. Introduction

• Retain everywhere seamless access to a rich set of information.• A global approach for providing IP-based mobility management

over various access technologies - 3G,4G cellular system are packet switched and have a micro- and pico-cellular networ

k structure

• Mobile IP offers a flexible mechanism but is non optimized to micro-mobility

- high handover rate

- signaling load to network

• Hierarchies to the mobility infrastructure

2. Domain Based Micro Mobility Supporting Protocols

• The approach of changing IP routing mechanisms

• Specialized path setup schemes are used to install host based routing information in specific routers

location update decrease

• In different network : Mobile IP as macro-mobility solution

• In home network : both Cellular IP and HAWII

Domain Based Wireless Access Networks and Mobile IP

2.1 Cellular IP 2.1.1 Network Architecture, Routing and Paging (cont.)

Cellular IP Wireless access network model

Routing

• Each Cellular IP node has an uplink neighbours and downlink neighbours

•

• The routing entries in the Cellular IP nodes are soft state

refresh periodically

Cellular IP nodeHost

route update message hop-by-hop

gateway router

reverse manner ( host based)

add a routing entry to a route cache

Paging mapping

• idle state : outdated route cache entries but valid paging cache

• active state : installed route cache entries

• The difference between the route cache and paging cache :

paging cache are not necessarily maintain and have longer timeout values

• When a mobile host receives packet

- idle state : broadcast to paging area

- active state : follow its movement

A Cellular IP Access Network Interconnected

to a Mobile IP enabled Internet

2.1.2 Handover Mechanisms (cont.)

• A handover is always initiated by the mobile host sending a route update message to the new base station.

• The path from the gateway router to the new base station may overlap with the path to the old base station

• Two mechanisms of handover • hard handover

- a simplistic approach to mobility management that support fast and simple handover - packet loss • semi-soft handover - algorithm that improves handover performance providing probabilistic guarantees instead of fully eliminating packet loss - send two route message

Cellular IP handover

2.2 HAWAII

• Domain-based approach for supporting micro-mobility called

Handoff-Aware Wireless Access Internet Infrastructure (HAWAII)

• Proposal to the IETF by researchers from Lucent Bell Lab

• Intra-domain mobility limited to access network

2.2.1 Network Architecture, Routing and Paging (cont.)

Routing

• Run a Mobile IP protocol engine

• Two sections of the processing of Mobile IP messages

- from the mobile host to the base station

- from the base station to home agent of the mobile host

• Three types of HAWAII path setup messages

- power-up

- update

- refresh

Paging

• Switch to a standby state

• A paging request is initiated

• Paging entries located in routing tables

• Entries updated by path setup messages and paging update messages

• Multicasted in paging area

• Paging areas defined by Multicast groups addresses

• Assign a co-located care-of address from foreign domain

2.2.2 Handover Mechanisms

• Use a tree-based topology

• Two different path setup schemes

- Network with mobile host that can only maintain connection to one base station (TDMA network)

- Network with mobile hosts that can be connected to two or more base stations simultaneously (CDMA network)

First scheme

1. Mobile IP registration request through Difference of both NAI

2. HAWAII path setup update message

3. Add routing table entry

4. Perform similar actions

5. Divert new data packet

6. Mobile IP registration reply

Forwarding path setup scheme

Second scheme

Non-forwarding path setup scheme

- Data packet are divert at the cross-over router

- No send packet in old BS

3. Protocol Reflections (cont.)

3.1 Host Based Routing and Paging

• Use host based routing within a limited access network

• Offer the possibility for mobile hosts to be paged

- Cellular IP : broadcast in the paging area

- HAWAII : By IP multicast group

3.2 Path Setup Scheme and Signaling

• Cellular IP 에서는 host 에서도 protocol 사용하지만 HAWAII 는호스트만제외하고사용 • Path setup in same way

3.3 Interaction with Mobile IP

• In Cellular IP

- The gateway router equal to Mobile IP foreign agent

• In HAWAII

- Assigned a co-located care-of-address from the address space of the visited HAWAII network

4. Conclusions

• The micro mobility management approach based two main hierarchy levels in conjunction with Mobile IP macro mobility

• Cellular IP and HAWAII offer very interesting solutions

• Better define the movement detection procedure and the handover execution decision