IDMP-based Fast Handoffs and Paging in IP-based Cellular Networks

IEEE 3G Wireless Conference, 2001

李威廷 11/22/2001

Telcordia

2

Outline Introduction IDMP Overview Fast Handoff Scheme in IDMP Paging Support in IDMP Conclusions

3

Introduction (1/3) Disadvantages of Mobile IP

High update latency Large global signaling load Lack of paging support

These problem are also present in various non-hierarchical MIP solutions

4

Introduction (2/3) The Intra-Domain Mobility Management

Protocol (IDMP) is proposed recently to reduce: the latency of intra-domain location updates

and the mobility signaling traffic.

5

Introduction (3/3) IDMP is conceptually a two-level

generalization of the Mobile IP architecture Mobility Agent (MA) provides a mobile node

(MN) a domain-wide stable point of packet redirection

IDMP can be combined with multiple global binding protocols With Mobile IP or SIP

6

7

IDMP Overview (1/3) IDMP is a multi-CoA intra-domain

mobility solution Unlike HAWAII, MIP-RR or HMIPv6,

IDMP is designed as a stand-alone solution for intra-domain mobility and does not assume the use of MIP for global mobility management

8

IDMP Overview (2/3) Mobility Agent (MA)

It is similar to a Mobile IP Regional Registration (MIP-RR) GFA

It provides an MN a stable global CoA Subnet Agent (SA)

It is similar to a MIP FA It provides subnet-specific mobility services

9

IDMP Overview (3/3) MN obtains two concurrent CoAs:

Local Care-of Address (LCoA) Similar to MIP’s care-of address Unlikely MIP, it only has local scope

Global Care-of Address (GCoA) Domain-level granularity

Fast Handoff Scheme in IDMP

11

Handoff Delay of IP-based BS (1/2) Radio-channel Establishment Delay (Δ1)

Establishing new radio-channel for new BS

IP Subnet Configuration (Δ2) SA mode:obtain an agent beacon and then

request a new LCoA Co-located mode: DHCP and then LCoA

Intra-domain Update Delay (Δ3) MN must inform the MA of its new LCoA

12

Handoff Delay of IP-based BS (2/2) Δ1 is expected to be quite low

CDMA-based soft handoff: Δ1 is 0

Old BS is not discontinued until the connection with the new BS is established

IDMP’s fast handoff process is designed to eliminate Δ3 , not eliminate Δ2

13

The Fast Handoff Procedure (1/2) Either MN or old SA generates

MovementImminent message to the MA Upon reception of this message, the MA

multicasts all inbound packets to the entire set of neighboring SAs

Each of these SAs buffers such arriving packets After MN performs a subnet-level configuration,

new SA forward all buffered packets.

14

15

The Fast Handoff Procedure (2/2) IDMP’s MovementImmient message does not

specify the IP address of the new BS Multicast forwarding is invoked concurrently

with subnet-level IP configuration phase, thereby reducing the Δ3

The MA decides (network-controlled) the set of target BSs to which in-flight packets are multicast

Only the new BS forwards arriving multicast packets to the MN

16

Implementing Fast Handoff IP multicast

The group membership is not dynamic PIM or DVMRP can be used to establish the

multicast tree Buffer size

(intra-domain update latency) * (incoming traffic rate)

17

Alternative Fast Handoff Suggestions Layer-2 trigger is used to cause old FA to

establish a transient tunnel to the new FA It eliminates Δ2, but authentication is only at

radio layer The MN initiate a new MIP registration

with the new FA through the old FA HMIPv4/v6 Does not provide network any control over

handoff process

Paging Support in IDMP

19

Paging Operation for Idle Hosts SAs are grouped into Paging Area (PA) The MN in passive/idle mode listens FA Agent

Advertisement to know which PA it belongs to MN Moving among the same PA does not update

MA about its current LCoA, and not obtain a new LCoA

The MA multicast a PageSolcitation packet to all the subnets associated with the MN’s current PA

20

21

Paging Implementation Paging Area Identifier (PAI) is used An SA can be associated with multiple PAs An MN must inform its MA when it

switches from the active to the idle state, thereby activating the paging functionality at the MA

22

Comparison with Alternative IP Paging Schemes IDMP does not need intermediate nodes

Only SA and MA take part in the paging process localize future upgrades

Paging operations are distributed among different MAs (each serving different MNs) There is no single point of failure for the

entire domain

23

Conclusions (1/2) IDMP is an IP-based hierarchical mobility

management and IP-based BS architecture Although the latency is higher than other

schemes that assume some layer-2 coordination, the temporary buffering mechanism provides acceptable latency variation

24

Conclusions (2/2) IDMP does not assume a tree-like topology

and allows easy configuration of variable-sized Pas

Implementation of IDMP Linux Mobile IP code (MosquitoNet Proj) MA daemon is modified from HA daemon