MONAMI6 WG, Internet-Draft (Informational), expires : may 22, 2008
Analysis of Multihoming in Mobile IPv6
draft-ietf-monami6-mipv6-analysis-04

Abstract

Mobile IPv6 allows a mobile node to maintain its IPv6 communication while moving between subnets. The current document investigates the situation where a IPV6 MN is multihomed, where the use of multiple addresses is foreseen to provide Ubiquitous, Permanent and Fault-tolerant access to the Internet. The current specification of MIPV6 lacks support for multihomed nodes.

This document aims to detail all the issues arising when MIPv6 operates on multihoed mobile nodes

Introduction

The emergence of new technologies has lead to more mobility within the Internet. To support this mobility, the Mobile IP version 6 (MIPv6) protocol has been designed.

However, this protocol doesn't take into consideration the requirements for ubiquitous, permanent, fault-tolerant and heterogeneous access to the Internet.

Two goals are assigned to this document : first, determine the capabilities required to provide ubiquitous, permanent, fault-tolerant and heterogeneous access to multihomed mobile nodes operating MIPv6; second, discuss the issues that arise when trying to fulfill these requirements.

The companion document to this is : "Motivations and Scenarios for Using Multiple Interfacesand Global Addresses", draft-ietf-monami6-multihoming-motivation-scenario-01, October 2006

Terminology

• MIPv6
• MN
• HA
• HoA
• CoA
• Simultaneously using multiple addresses
• Simultaneously using multiple interfaces
• BT Mode : MIPv6 Bidirectional tunnel between MN and HA
• RO Mode : MIPv6 Route Optimization between MN and CN

Multihomed MN

There are 2 basic cases when a MN is said to be multihomed. Either it uses mutliple addresses as source address or it has many tunnels to trasmit packets to, or even both.

Multiple tunnels

The very basic cases when a MN is said to have multiple tunnels are when

• First, it has multiple HoAs, that is multiple prefixes are available on the home link or if it has multiple interfaces named on distinct home links.
• Second, it has multiple CoAs, that is multiple prefixes are available on the foreign link or if it has multiple interfaces attached to distinct foreign links
• Third, the HA has multiple addresses

Goals and Node Capabilities

In this section, the capabilities required on the MIPv6 MN to benefit from multihoming configurations are defined.

A number of goals/benefits are also defined, namely :

• Ubiquitous access
• Flow redirection
• Reliability
• Load sharing
• Interface switching
• Preference settings
• Aggregate bandwith

Goals (Non-overlapping)

The following non-overlapping goals could be extracted :

1. Reliability
2. Load sharing
3. Flow distribution

Capabilities (Result from goals)

In order to meet some of the goals defined earlier, the following capabilities must be enabled:

• Quickly activate a backup interface and redirect traffic
• Quick redirection of flows from address to another
• Triggers of flow redirection
• Simultaneous use of multiple valid addresses
• Simultaneous use of multiple interfaces
• Traffic load distribution among global addresses
• Simultaneous use of multiple HAs (when available)

Taxonomy

Multihoming configurations

(More coming soon...)