[45050] in North American Network Operators' Group
RE: router startup behavior
daemon@ATHENA.MIT.EDU (David Schwartz)
Mon Jan 14 15:33:12 2002
From: David Schwartz <davids@webmaster.com>
To: <nanog@merit.edu>
Date: Mon, 14 Jan 2002 12:32:12 -0800
In-Reply-To: <004001c19d31$ad07c350$ac60260a@interaccess.com>
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On Mon, 14 Jan 2002 13:28:42 -0600, Steve Naslund wrote:
>Here is my best guess as to what you are seeing. Most likely a=
large CIDR
>block is announced by a service provider A. A small CIDR block=
is given to
>a customer who is connected to multiple service providers and=
thus running
>BGP. Now the more specific route is announced by service=
provider B, he
>does not own the block but is announcing it on behalf of service=
provider As
>customer. What is happening is that the customer has a line or=
router
>failure and that withdraws their more specific announcement from=
service
>provider B. Since the service provider A is announcing a=
supernet route he
>now becomes the only route for that block.
=09If that's the problem, a fix might be to not advertise any=
routes to a BGP
peer until you receive all the routes that peer has to send you.=
I think it's
elegant that when two routers connect, neither sends any routes=
to the other
until each has received all the routes the other has to send.=
Very Zen, don't
you think?
=09DS
