nanog mailing list archives
Re: Strange practices?
From: Steve Bertrand <steve () ipv6canada com>
Date: Mon, 07 Jun 2010 18:00:03 -0400
On 2010.06.07 17:49, Murphy, Jay, DOH wrote:
"Has anyone ever heard of a multi-homed enterprise not running bgp with either of 2 providers, but instead, each provider statically routes a block to their common customer and also each originates this block in BGP?� As stated before...yes this is a common practice. "One of the ISP's in this case owns the block and has even provided a letter of authorization to the other, allowing them to announce it in BGP as well.� Yes, one ISP owns the block, both will aggregate the blocks and announce the blocks to the global internet. BGP attributes will shape best path for routing; i.e., AS-PATH, ORIGIN, LOCAL PREF. MEDS should take care of "leaking" routes. So, is this design scheme viable? Yes, it is.
I understood the OP's question as one of concern. It sounds to me like one of their ISPs can't/won't/doesn't know how to configure a client-facing BGP session. I've run into this before, and it was due to a lack of understanding/clue of how to peer with a multi-homed client when the client didn't have their own ASN. If that is the case, then I'd be concerned about situations where the link goes down, but the advertisement is not removed from their DFZ-facing sessions, possibly causing a black hole for traffic transiting that ISP. The work involved in co-ordinating two ISPs to detect and protect against this type of situation is far more difficult than just configuring BGP from the client out (imho). Steve
Current thread:
- Strange practices? Dale Cornman (Jun 07)
- Re: Strange practices? Florian Weimer (Jun 07)
- Re: Strange practices? Brian Feeny (Jun 07)
- Re: Strange practices? Brian Feeny (Jun 07)
- Re: Strange practices? Brian Feeny (Jun 07)
- Re: Strange practices? Joe Provo (Jun 07)
- Re: Strange practices? sjk (Jun 07)
- Re: Strange practices? joel jaeggli (Jun 07)
- Re: Strange practices? Bill Fehring (Jun 07)
- RE: Strange practices? Murphy, Jay, DOH (Jun 07)
- Re: Strange practices? Steve Bertrand (Jun 07)
- RE: Strange practices? Murphy, Jay, DOH (Jun 07)
- Re: Strange practices? Steve Bertrand (Jun 07)
- Re: Strange practices? Steve Bertrand (Jun 07)
- Re: Strange practices? Florian Weimer (Jun 07)
- Re: Strange practices? Jen Linkova (Jun 08)
- <Possible follow-ups>
- Re: Strange practices? deleskie (Jun 07)
- RE: Strange practices? Murphy, Jay, DOH (Jun 07)
- Re: Strange practices? Steve Bertrand (Jun 07)
- Re: Strange practices? Dorn Hetzel (Jun 07)
- RE: Strange practices? Murphy, Jay, DOH (Jun 07)
- RE: Strange practices? Murphy, Jay, DOH (Jun 07)
- Re: Strange practices? Steve Bertrand (Jun 07)
- Re: Strange practices? Steve Bertrand (Jun 07)