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Re: v6 multihoming and route filters

Le 06-07-03 à 14:46, Kevin Loch a écrit :



On the subject of route filtering, it's not a simple as "here is the
limit, this is ok and this is not".  There are different consequences
for prefixes accepted vs those originated or readvertised.


sure, that is the whole idea of the draft.



Here is a possible filtering recommendation which uses the
"be conservative in what you send but liberal in what you accept"
philosophy and covers the various situations:
ok. I agree in principle on what you wrote below. I see from your contributed text below two concepts: 
a) "generic"/well-known filtering recommendations (applicable to v4 too)
b) specific to ipv6 around "no longer than /48"

I was not going too much around a) because a) is covered elsewhere.
What is on debate is b). And again, b) is what I'm proposing since the first (personal) version of the draft: 
- filter/do not advertise any prefix longer than /48.
If we agree on this (filter/do not advertise any prefix longer than / 48), than I'll put it back into the draft! 

Marc.



Received:
- Routes from customers:  Operators may accept any prefixes from
customers, if the prefixes (or parent) are delegated to the customer. 
- Routes from peers/transit:  Operators may accept any prefixes from
peers/transit they want, and may reject any prefixes they don't want. 
  it is recommend they not accept prefixes longer than /48.

Announced:
- Routes originated by an ASN:  Operators should whenever practical
minimize the number of prefixes they originate, ideally only the exact 
  prefixes delegated by an RIR.  Steps must be taken to prevent
  unintentional origination of more specifics.
- Routes originated by an ASN and announced to an upstream provider:
  Prefixes of any length  may be advertised to an upstream but steps
should be taken by one or both parties to prevent prefixes longer than 
  /48 or unintentional deaggregates from being readvertised.
- Routes readvertised by an ASN:  Operators should (must?) not
  readvertise any prefix longer than /48.

- Kevin




=========
IPv6 book: Migrating to IPv6, Wiley, 2006. http://www.ipv6book.ca