[c-nsp] BGP Advertising - Question re more specific block

[Paul Stewart]

Hi Steve..

That is correct - we will actually be taking any specifics and tagging them
with one community.  We will use that community only with certain upstream
and peering points.

Our overall problem is that we have one upstream that we are stuck with in
contract and are not remotely meeting our minimum traffic levels with them -
if we start prepending then we get too large of a traffic shift.  So I'm
hoping to take a few /22 and maybe a /20 and advertise it as a more specific
route to that upstream and also to our peering points (we don't want to push
any traffic away from peering points of course).

Thanks,

Paul


-----Original Message-----
From: Steve Bertrand [mailto:steve at ibctech.ca] 
Sent: Thursday, June 04, 2009 9:02 AM
To: Paul Stewart
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] BGP Advertising - Question re more specific block

* PGP - S/MIME Signed by an unverified key: 06/04/09 at 09:01:56

Paul Stewart wrote:

> We are advertising a specific /22 that belongs to a /18 block via one
> specific upstream BGP connection.  The /18 is advertised to all upstreams,
> the /22 is only advertised to one upstream as a method of influencing
> traffic via that carrier (knowing that if that particular carrier went
down,
> the less specific subnet will still be reachable via the other providers).
> Prepending is very ugly for this situation FYI.

Paul,

Just so I can get a better understanding, you are applying a community
to each /22 you are advertising to certain peers.

You are then applying a route-map to a particular peer, that only sends
the prefixes that have a particular community set. Is this correct?

Do you advertise this exact group of /22's to more than one upstream peer?

Steve

* Thawte Freemail Member <steve at ibctech.ca>
* Issuer: Thawte Consulting (Pty) Ltd. - Unverified