Transcript THE IP MOBILITY APPROACH

THE IP MOBILITY APPROACH
발표자 : 이진우
Tables
1. Introduction
2. 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 Mechanisms
3. 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 ov
er various access technologies
- 3G,4G cellular system are packet switched and have a micro- and pico-cellular
network 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
Cellular IP node
gateway router
• Host
route update message
hop-by-hop
add a routing entry to a route cache
reverse manner ( host based)
• The routing entries in the Cellular IP nodes are soft state
 refresh periodically
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• idle state : outdated route cache entries but valid paging cache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
- Data packet are divert at
the cross-over router
- No send packet in old BS
Non-forwarding path setup scheme
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 host에서도 protocol 사용하지만
HAWAII는 호스트만 제외하고 사용
• 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