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 documents of the Internet Engineering Task Force (IETF), its areas, and working groups. Note that other groups may also distribute working documents as Internet Drafts. Internet Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 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