1. Mobile IP Regional Registration
Sasikanth Avancha
CMSC 691T
Spring 2000

2. Motivation
Terminology
Protocol Description
Router Discovery Extensions
Regional Extensions
Authentication Extensions

3. Motivation Reduce signaling delay for registrations
Reduce number of signaling messages sent to HA
Possibly improve hand-off performance

4. Terminology GFA – Gateway Foreign Agent RFA – Regional Foreign Agent
NAI – Network Address Interface
HFA – Hierarchical Foreign Agent
COA – Care-of Address
RRQ – Registration Request
RRP – Registration Reply
AAA Server

5. The Protocol Overview MH at home behaves as required by RFC 2002
MH in a visited domain
Registers with HA when it first enters the visited domain; MAY set GFA as care-of address
Registers with GFA on subsequent moves within domain; MAY set RFA as care-of address
Receives data traffic from CH as described in RFC 2002

6. The Protocol
FA, RFA, GFA
FA MAY advertise itself and/or RFA(s); MUST advertise GFA
Advertisements have I-bit set to indicate regional registration support
Ads with only GFA MUST include FA NAI extension
FA adds HFA extension to RRQ with COA field == 0
FA sends RRQ directly to HA if COA == FA
GFA maintains binding for MH

7. The Protocol HA Sets GFA, RFA or co-located address as COA for MH
Distributes registration key to MH and GFA
Encapsulates datagrams and tunnels to GFA

8. Extensions Router Discovery Regional Tunnel Management Flag: the I-bit
FA NAI Extension
A string in the NAI format; SHOULD appear in Agent Adv
RRP Flags: unknown GFA, GFA unreachable (host, port, other)

9. Extensions Regional GFA IP Address extension HFA extension
Contains publicly routable IP address of GFA
Added to RRQ by FA if COA field is 0
HFA extension
Contains IP address of FA the MH has chosen as COA
GFA uses it to create binding for MH

10. Extensions Authentication Replay Protection FA-FA authentication
Contains replay protection style and initial identification
Authentication
FA-FA authentication
MH-GFA authentication
Used whenever MH has co-located COA
Used to authenticate Regional RRQ

11. Reference
Gustafsson et al, Mobile IP Regional Registration, IETF Internet Draft (Work in Progress; expires Sept 6, 2000)