6:32 a.m.
Hi Steve,
Well AARNet still lists their communities (someone like Warrick would
need to confirm if they still use them or not) but it doesn't scale to
collect together someone else's communities and try to use them.
As a community you need to identify a collection of networks that makes
sense as a collective of ASes where a similar routing decision might be
helpful and then assign that a community and get all those ASN tagged
with that community so that another network can make a routing decision
based on it. The aim here is to help cut out unnecessary trans oceanic
transits that might happen because BGP is just doing an AS hop count and
that is a poor indicator of high performance connectivity and latency.
For example, NORDUNet might see SINET via Géant and Internet2. If SINET
is tagged with an "east Asia" community then NORDUNet might have a
routing policy that says that Géant is the best way to reach east Asia
irrespective of BGP as-path length as the path across Eurasia is
"better" than going across the Atlantic, continental US and the Pacific.
Hopefully SINET would have a similar rule.
Mark.
On 1/4/2024 21:10, Steven Wallace wrote:
Mark,
That’s a great suggestion. I believe Internet2 used to publish a set of community tags
that attempted to provide this capability. I’m looking through old records to see if there
is anything worth reusing or learning from.
Steve
On 1 Apr 2024, at 9:58, Mark Prior wrote:
On 1/4/2024 20:40, Steven Wallace wrote:
Steven Wallace
Director - Routing Integrity
Internet2
ssw(a)internet2.edu Based on the feedback from this list, I’ve put
together a rough draft of a best practice. Anyone can add comments to the Google Doc. If
you’d like to edit the document directly, please send me your email, and I’ll add you to
the document’s authors.
I would suggest that you develop a mutual set of communities to indicate if a prefix is a
customer or a transit receiving peer, and which continent the prefix lives on so that some
sensible pruning could be attempted. As an example it would probably be helpful for Géant
to know if Internet2 is sending prefixes from South America or Africa as they possibly
have a better path to those locations and would want to depreference an Internet2 version
even if the AS path was shorter. If there are regions with limited connectivity options
than enumerating them might be helpful.
Mark.