Re: [nsp] BGP Multihome

From: Jay Borkenhagen (jayb@braeburn.org)
Date: Sat Aug 26 2000 - 12:00:39 EDT


>>>>> Philip Smith <pfs@cisco.com> writes:

pfs> At 09:59 25/08/00 -0400, OZhang@tsibroadband.net wrote:
>> Thanks for the suggestion. I'd assume that the customer can use
>> the same private AS to peer with both us and the other service
>> provider, correct ?

pfs> Yes, the customer has to do this. It's like a normal multihoming,
pfs> just using a private AS.

Umm, is that really the advice we should be giving? To my mind, if a
network is connected to multiple service providers, a public AS number
is needed and it should be connected to all the multiple providers.
Private AS numbers have their place, but not for multi-provider
connectivity.

As per rfc1930:

 7. One prefix, one origin AS

   Generally, a prefix can should belong to only one AS. This is a
   direct consequence of the fact that at each point in the Internet
   there can be exactly one routing policy for traffic destined to
   each prefix. [...]

To simultaneously satisfy the two goals that (1) each prefix should
originate in a unique AS number, and (2) private AS numbers must be
seen in the core of the Internet, a unique public AS number must be
used.

Thanks.
                                        Jay B.

-- 
  Jay Borkenhagen     jayb@braeburn.org



This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:15 EDT