SIG: Routing

Wednesday 4 September, Kitakyushu International Conference Centre, Kitakyushu, Japan


Meeting commenced: 9:00am

Chair: Philip Smith

The Chair introduced the SIG and explained the agenda.

  1. Routing reports update
  2. IP Anycast for Distributed DNS Services
  3. Best practices for ISPs

  1. Routing reports update
  2. [Presentation]

    Geoff Huston, Telstra

    This presentation provided an overview of routing table developments since the introduction of CIDR in 1994, particularly trends observed in 2001-2002. Analysis of global routing tables suggests that the growth rate in 2002 has returned to the growth rate seen during 1994 - 1997. That is, the routing table seems to have resumed a linear rather than exponential growth.

    In 2002 the growth of visible address space appears to be slowing. This may be due to more sophisticated address policies by RIRs/NIRs that require more detailed information for address requests. This may be leading a number of networks to use private address space and NAT as a more cost effective and cheaper alternative for large scale deployment.

    The presentation suggested that the growth of Autonomous Systems may be a more effective way to judge the growth of the routing table as the growth of ISPs choosing to multihome complicates the use of prefixes announced to assess the routing table growth.

    The presenter demonstrated the information available in the CIDR report at http://www.cidr-report.org that can assist network managers aggregate their announced routes. He noted that the report demonstrates that the underlying complexity of the routing table is growing at a slower rate than the actual number of entries in the routing table.

    Questions and discussion

    • There was a discussion about using the routing reports to assess the effect of route dampening. It was explained that there needs to be a per-prefix database to track the withdrawals effectively. The presenter is planning to create such a database.

    Action items

    • None


  3. IP Anycast for Distributed DNS Services
  4. Bill Woodcock, Packet Clearing House

    This presentation outlined the use of anycast IP addressing. Defined in RFCs since the early 1990s, anycast has been gaining popularity in DNS infrastructure. In the last two or three years, most major ISPs have been running anycast DNS servers within their POPs. The presentation explained how to implement and finetune anycast networks to distribute load balance among a number of servers.

    Questions and discussion

    • There was discussion about the stability of long life flows. In the case discussed, TCP anycast was used for a network, where if anycast had not been implemented, 200Mbps would have been required on a backbone capable of much less. Using anycast allowed traffic to be drawn away from the backbone.
    • A member of the audience drew attention to a paper by Dan Massey suggesting that gTLD and root servers should be less static to prevent attackers. The paper suggests that ISPs should make the routes to the TLD and root servers more stable. However, it was noted that anycasting does the opposite. It was suggested that networks should not use anycast for essential services until DNSSEC is implemented. The speaker appreciated the point, but disagreed. This remains an ongoing debate in the community.

    Action items

    • None


  5. Best practices for ISPs
  6. [Presentation]

    Ahmer Ghazi, Sysnet

    Unfortunately the speaker was unable to attend the SIG.

Meeting closed: 11:20am

Minuted by: Sam Dickinson

Open action items
  • None

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