1. IDMP: AN INTRADOMAIN MOBILITY MANAGEMENT PROTOCOL FOR NEXT-GENERATION WIRELESS NETWORK
SUBIR DAS, ANTHONY MCAULEY AND ASHUTOSH DUTTA, TELCORDIA TECHNOLOGIES INC.
ARCHAN MISRA, IBM T. J. WATSON RESEARCH CENTER
KAUSHIK CHAKRABORTY, UNIVERSITY OF MARYLAND
SAJAL K. DAS, THE UNIVERSITY OF TEXAS AT ARLINGTON
IEEE Wireless Communications • June 2002
Reporter：Chun - I Chen

2. Outline IDMP Overview The architecture of IDMP Handoff Paging
Comparison
Conclusion

3. IDMP
IDMP is a two-level generalization of the Mobile IP architecture, with a special node called the mobility agent (MA) providing an MN a domain-wide stable point of packet redirection
It will be independent of any specific solution for global (interdomain) mobility management
IDMP offers intradomain mobility by using multi-CoA
The mobility agent (MA) is similar to a MIP-RR GFA and acts as a domain-wide point for packet redirection
A subnet agent (SA) provides subnet-specific mobility services

4. Architecture Functional Specification
Internet HA CN MA
GCoA
SA1
SA2
SA3
SA4
Subnet A
Subnet B
Subnet C
Subnet D MN
LCoA

5. IDMP (cont’d) Local care-of address (LCoA)
This identifies the MN’s attachment to the subnet
Unlike MIP’s CoA, the LCoA in IDMP only has local scope
By updating its MA of any changes in the LCoA, the MN ensures that packets are correctly forwarded within the domain
Global care-of address (GCoA)
This address resolves the MN’s current location only up to a domain-level granularity and hence remains unchanged as long as the MN stays within a single domain
By issuing global binding updates that contain this GCoA, the MN ensures that packet are routed correctly to its present domain

6. The architecture of IDMP

7. Architecture Functional Specification
Foreign Agents/ DHCP(DRCP) Servers at the subnet level
Provide MN with a locally-scoped address which identifies mobile location within the domain.
Mobility Agents (MA) distributed within the domain
Multiple MAs for load-balancing and redundancy within the domain.
Provides MN with a global care-of address that stays constant within the domain. MN’s location is globally known only up to the MA-level granularity.
In current implementation (in this paper), HA/CNs as in conventional Mobile IP

8. Architecture Functional Specification
MN retains the same MA (global care-of address) within the same domain
All packets from the global Internet tunneled to the MA, which acts as a single point of enforcement/accounting.
MA tunnels these packets to MN’s current LCOA.
On subsequent movement within the domain, MN only obtains a new local COA.
No need to update the HA or CNs.
MN updates its MA with its new local COA.

9. Basic Architectural Features
A multi-CoA Intradomain mobility solution
MA->GFA /SA->FA
Each MN obtains two concurrent CoAs, LCoA and GCoA
MN updates its MA with its new LCoA at every Intradomain Handoffs, while it updated its HA with GCOA during any interdomain handoff
Multiple MAs in a domain
Load balancing

10. Path setup At power-up, MN obtains a LCoA from SA
In IDMP’s SA mode, MN must obtain LCoA from Agent Advertisement of its SA
In collocated mode, MN obtains its LCoA from DHCP server
MN receives MA’s CoA, GCoA, from SA or DHCP server
MN informs the MA of its new LCoA using intradomain location update msg and updates its HA with GCOA
Now, packers from remote CN are forwarded to MN’s GCoA and intercepted by MA, tunnels them to MN’s current LCoA

11. IDMP message flow during the initial intradomain location update

12. IDMP call flow during subsequent intradomain movement

13. Handoff
MN moves from SA2 to SA3 subnet, MN or SA2 generated movementImminent msg to MA
On reception of this msg, MA multicasts all inbound packets to the entire set of neighboring SA(SA1,SA3) which buffer them in per-MN buffers
When MN performs a subnet-level registration with SA3, SA3 can immediately forward all buffered packets to the MN
Buffered packets at other SAs are discarded after specified time
MN updates the MA with its intra-domain location

14. Paging Paging Area A set of subnets
An idle MN updates its location only if it detects moved out of its current PA
When MA receives packets for a MN which is currently registered but in idle mode, it multicasts Page Solicitation packet to all subnets in current PA
When the dormant MN is paged, it obtains LCoA from the SA to which it is currently attached and sends a location update to the MA
When the MN reregisters with the MA, the buffered packets in the MA are forwarded to the MN

15. Micro-Mobility Solutions
To reduce signaling load and delay to the home network during movements within one domain
Tunnel-based micro-mobility schemes
Mobile IP regional registration (MIP-RR)
Hierarchical Mobile IP (HMIP)
Intradomain mobility management protocol (IDMP)
Routing-based micro-mobility schemes
Cellular IP (CIP)
Handoff Aware Wireless Access Internet Infrastructure (HAWAII)

16. Simple Comparison CIP/HAWAII IDMP Handoff/ Path setup Routing
Table update
Tunnel
Update
Paging
Paging cache
/Multicast
Multicast
Function
Deployment
All nodes
Some nodes

17. Cellular IP architecture

18. 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

19. Cellular IP 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

20. HAWAII architecture

21. HAWAII-suboptimal routing problem
Cellular IP W0 －＞ W4 －＞ AP8
HAWAII W0 －＞ W1 －＞ W2 －＞ W3 －＞ W4 －＞ AP8

22. Conclusion