nanog mailing list archives
Re: Who has AS 1712?
From: Randy Bush <randy () psg com>
Date: Wed, 25 Nov 2009 13:58:28 +0900
Right. You can't advertise an ASN you can only advertise a route and include an AS_PATH attribute on it which makes mention of a particular AS number.
that bit of biff-like pedantry quickly leads to you can't advertise a prefix. a bgp announcement has, in the case of ip unicast, an nlri and, among other things, an as-path. see rfc 1771 4.3 on Path Attributes. as to what is being announced and what is merely loitering waiting for a hot pick-up, you can work that out with your mullah, priest, rabbi, spouse, ... for unusual utility of intentionally announcing a particular asn, see as-path poisoning, e.g. lorenzo's thesis [0], the talk which was banned at nanog [1], or the full paper [2].
My point is that in the absence of any mechanism for announcing an ASN, a plan to gate assignment of numbers based on an announcement doesn't make any sense.
seeing if an asn is in a currently-announced as-path is useful, as has been pointed out in this discussion. and it very well might have caught the problem at hand. the problem is that it is far from definitive as bgp presents a highly biased view (see [1] and [2]), and an asn may be held but not announced. but, as chris morrow said, every little bit helps. randy -- [0] - http://www.colitti.com/lorenzo/publications/phdthesis/thesis.pdf [1] - http:archive.psg.com/091006.nag-default.pdf [2] - http://portal.acm.org/citation.cfm?id=1644893.1644923&coll=portal&dl=ACM&type=series&idx=SERIES10693&part=series&WantType=Proceedings&title=IMC acm member portal, sorry. those really interested, email me for a copy
Current thread:
- Re: Who has AS 1712?, (continued)
- Re: Who has AS 1712? Jon Lewis (Nov 23)
- Re: Who has AS 1712? Stephane Bortzmeyer (Nov 23)
- Re: Who has AS 1712? Stephane Bortzmeyer (Nov 23)
- Re: Who has AS 1712? Christopher Morrow (Nov 23)
- Re: Who has AS 1712? Jon Lewis (Nov 23)
- Re: Who has AS 1712? Christopher Morrow (Nov 23)
- Re: Who has AS 1712? Edward Lewis (Nov 24)
- Re: Who has AS 1712? Joe Abley (Nov 24)
- Re: Who has AS 1712? Randy Bush (Nov 24)
- Re: Who has AS 1712? Joe Abley (Nov 24)
- Re: Who has AS 1712? Randy Bush (Nov 24)
- Re: Who has AS 1712? Joe Abley (Nov 24)
- Re: Who has AS 1712? Christopher Morrow (Nov 24)
- Re: Who has AS 1712? Joe Abley (Nov 25)
- Re: Who has AS 1712? Jon Lewis (Nov 24)
- Re: Who has AS 1712? Stephane Bortzmeyer (Nov 25)
- Re: Who has AS 1712? Michael Dillon (Nov 26)
- Re: Who has AS 1712? Randy Bush (Nov 23)
- Re: Who has AS 1712? Florian Weimer (Nov 24)
- Re: Who has AS 1712? John Curran (Nov 24)
- Re: Who has AS 1712? Larry Blunk (Nov 24)