Internet DRAFT - draft-dommety-mobileip-min-handoffv4and6
draft-dommety-mobileip-min-handoffv4and6
Personal
INTERNET DRAFT Gopal Dommety
Category: Informational cisco Systems
Title: draft-dommety-mobileip-min-handoffv4and6-00.txt
July 2001
Expires December 2001
Handoff Optimization with no prediction and minimal L2 Trigger information
draft-dommety-mobileip-min-handoffv4and6-00.txt
Status of this Memo
This document is a submission by the mobile-ip Working Group of the
Internet Engineering Task Force (IETF). Comments should be submitted
to the MOBILE-IP@STANDARDS.NORTELNETWORKS.COM mailing list.
Distribution of this memo is unlimited.
This document is an Internet Draft and is in full conformance with
all provisions of Section 10 of RFC2026. Internet Drafts are working
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Abstract
Currently Mobile IP WG is carrying out very interesting work in the
area of Fast/Low latency handoffs for Mobile IPv6 and Mobile IPv4. The
high level goal of this work is to reduce the latency during the
change of point of attachement to the Internet (AKA Handoff) This
document discusses one simple case that in the author's opinion is
very common and can be optimized to achevie lower latency than that
proposed by the various solutions. This scenario applies to both IPv6
and IPv4 work. The solution at a high level is the same, but
realization will be different as the frame work in IPv6 case is
different from that of the IPv4 case.
1. Introduction
Currently Mobile IP WG is carrying out very interesting work in the
area of Fast/Low latency handoffs for Mobile IPv6 and Mobile IPv4. The
high level goal of this work is to reduce the latency during the
change of point of attachement to the Internet (AKA Handoff) This
document discusses one simple case that in the author's opinion is
very common and can be optimized to achevie lower latency than that
proposed by the various solutions. This scenario applies to both IPv6
and IPv4 work. The solution at a high level is the same, but
realization will be different as the frame work in IPv6 case is
different from that of the IPv4 case.
2. Senario Description
When the mobile moves from one AR to another the following scenarios
can be envisioned in the break-before make case of handoff.
1. We can predict the movement in advnace (i.e. before the handoff)
and enable fast handoff as described in [FMIPv6] and in
PRE-REGISTRATION HANDOFF of FMIPv4.
2. We can use L2 trigger information intelligently as specified in
POST-REGISTRATION in FMIPv4 and in Extension to FMIPv6 in BETH.
There is a scenario where it is not possible to predict the movement
well ahead in advance and sufficient L2 Triggers are not avialable. In
this scenario the mobile moves to a new access router would like to
affect a fast handoff. The goal of this document is to suggest
solutions to achenving this handoff in a least latency fashion. An
example network where in such a scenario occurs is Wireless LAN or
802.11 based network. In this scenario, and in the absense of
appropriate L2 triggers, the handoff currently prescribed is that of
one specified in Mobile IPv6 or Mobile IPv4.
3. Handoff for IPv6
3.1 Problem
Currently in IPv6, in the above described scenario, the mobile needs
to obtain a CoA using a stateless (obtain the network prefix, form a
CoA, perfom DAD) or stateful mechanisim. Then perform Mobile IPv6
procedures. This will incur latency beyond what is acceptable for
realtime communicaiton.
3.2 Solution
There are several possible implementations/realizations
Implementaion 1.
+-----+ 2HI*/HRqst*[FBack*]+-----+
| | -----------------> | |
| oFA | | nFA |
| | 3.HAck*/HRply* | |
+-----+ <----------------- +-----+
\
\ |
1. FBu* \ |
\ | 4. FBAck*
\ v
+-----+ Movement +-----+
| MN | - - - - - - - - -> | MN |
+-----+ +-----+
Implementation 2.
+-----+ 3. HAck*[FBack*] +-----+
| | -----------------> | |
| oFA | | nFA |
| |2.HI*/HRqst*[FBu*] | |
+-----+ <----------------- +-----+
^ |
1. FBu* | | 4. FBAck
| v
+-----+ Movement +-----+
| MN | - - - - - - - - -> | MN |
+-----+ +-----+
Implementation 3.
+-----+ 2. HI*/HRqst[FBack]+-----+
| | -----------------> | |
| oFA | | nFA |
| | 3.HAck*/HRply* | |
+-----+ <----------------- +-----+
\ \
V ^
\ \
1. FBu* \ \
\ \ 4. FBAck*
\ \ v
+-----+ Movement +-----+
| MN | - - - - - - - - -> | MN |
+-----+ +-----+
Other variations of implementations are possible.
This soltion is an extension to FMIPv6 and BETH drafts. *denotes
extension to the current functionaly of the maeesages.
3.3 L2 Assumptions
3.4 Issues:
3.4.1 How to determine the IP/MAC address of the nFA?
3.4.2 Movement detection
3.4.3 Ingress Filterning
3.4.4 Security
3.5 Benifits
3.6 Buffering
3.7 Bicasting
4. Solution in IPv4
4.1 Problem
With the fast handoff soltions that have been proposed in FMIPv4. The
mobile has to perform Mobile IP registration. Which incurs latency as
discussed earlier.
4.2 Solution
In this case too there There are several possible implementations. One
such implementaion is:
+-----+ 2.Handoff Request* +-----+
| | <----------------- | |
| oFA | | nFA |
| | 3.Handoff Reply* | |
+-----+ -----------------> +-----+
^ |
1. Reg Request* | | 4. Reg Reply*
| v
+-----+ Movement +-----+
| MN | - - - - - - - - -> | MN |
+-----+ +-----+
#From the figure it looks like a re-ordering of the messages. But this
#is actually more than than
Other variations of implementations are possible.
This soltion is an extension to [FMIPv4].
*denotes extension to the current functionaly of the messages.
4.3 L2 Assumptions
4.4 Issues:
4.4.1 How to determine the IP/MAC address of the nFA?
4.4.2 Movement detection
4.4.3 Ingress Filterning
4.4.4 Security
4.4.5 Buffering
4.4.6 Bicasting
4.5 Benifits
5. References
[MIPv4] C. Perkins. IP Mobility Support. Request for Comments
(Proposed Standard) 2002, Internet Engineering Task Force,
October 1996.
[FMIPv4] El-Malki, K., et. al., "Low Latency Handoff in Mobile IPv4,"
draft-ietf-mobileip-lowlatencyhandoffs-v4-01.txt, a work in
progress.
[FMIPv6] Tsirtsis, G., "Fast Handovers for Mobile IPv6," draft-ietf-
mobileip-fast-mipv6-01.txt, a work in progress.
[MIPv6] Johnson, D., and Perkins, C., "Mobility Support in IPv6," draft-
ietf-mobileip-ipv6-13.txt, a work in progress.
[BETH] Kempf, J., et al. "Bidirectional Edge Tunnel Handover for
IPv6," draft-kempf-beth-ipv6-01.txt, a work in progress.
Dommety [Page 4]
Internet Draft
Authors Information
Gopal Dommety
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134
e-mail: gdommety@cisco.com
Expires December 2001
