Technology - IP Routing & Addressing Crisis 1 - User Requirements

Synopsis

We present an overview of the conflicts between different aspects of the Internet’s routing and addressing systems, including between the need for multihoming, route aggregation and efficient address utilisation. We discuss the exhaustion of IPv4 address space, the needs of end-users and of ISPs, constraints on possible solutions and the limitations of the BGP routing system, which lie at the heart of the crisis in routing and addressing.

Table of Contents

• 1. Synopsis
• 2. Introduction
• 3. Routing and Addressing Problem (ROAP)
  • 3.1 The Internet only just works
  • 3.2 IAB Workshop on Routing and Addressing
  • 3.3 Needs and problems
  • 3.4 Constraints on possible solutions
• 4. Needs and desires
  • 4.1 ISPs and AS-end-users
    • 4.1.1 Multihoming
    • 4.1.2 Traffic engineering
    • 4.1.3 Burden on BGP
    • 4.1.4 Efficient utilisation of address space
  • 4.2 Domestic and SOHO end-users
• 5. Route aggregation and address utilisation
  • 5.1 Prefix and subnet terminology
  • 5.2 Best case route aggregation
  • 5.3 Worst case route disaggregation
    • 5.3.1 Aggregation at distant routers
  • 5.4 Improving route aggregation
  • 5.5 Aggregation can improve with distance
  • 5.6 Provider Aggregated (PA) Addresses
    • 5.6.1 Lack of portability
• 6. Multihoming
  • 6.1 Two or more links to ISPs
  • 6.2 Provider Independent (PI) address space required
  • 6.3 Diversity is at odds with route aggregation
  • 6.4 BGP stability and multihoming
• 7. Related reports