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Odd BGP AS Path


From: Heath Jones <hj1980 () gmail com>
Date: Wed, 22 Sep 2010 16:18:15 +0100

Hi all,

Probably a silly question, but can anyone explain to me this:
3561 3356 9031 {35821,35821,35821,35821} i

To explain it a bit better, I'm looking at real routing information
from routeviews (#3).

According to RFC 4271 (9.2.2.2 Aggregating Routing Information):
For the purpose of aggregating AS_PATH attributes, we model
each AS within the AS_PATH attribute as a tuple <type, value>,
where "type" identifies a type of the path segment the AS
belongs to (e.g., AS_SEQUENCE, AS_SET), and "value" identifies
the AS number.
...
No tuple of type AS_SET with the same value SHALL appear
more than once in the aggregated AS_PATH.

Am I misreading things, or is this path information out of spec?


Cheers
Heath


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