[138806] in North American Network Operators' Group
RE: bfd-like mechanism for LANPHY connections between providers
daemon@ATHENA.MIT.EDU (Jensen Tyler)
Wed Mar 16 16:43:30 2011
From: Jensen Tyler <JTyler@fiberutilities.com>
To: Jeff Wheeler <jsw@inconcepts.biz>, "nanog@nanog.org" <nanog@nanog.org>
Date: Wed, 16 Mar 2011 15:42:39 -0500
In-Reply-To: <AANLkTin6xNZg=5i_yEBfDnzGE7z89ByKNRsnrigN-GOr@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Correct me if I am wrong but to detect a failure by default BGP would wait =
the "hold-timer" then declare a peer dead and converge.
So you would be looking at 90 seconds(juniper default?) + CPU bound converg=
ence time to recover? Am I thinking about this right?
-----Original Message-----
From: Jeff Wheeler [mailto:jsw@inconcepts.biz]=20
Sent: Wednesday, March 16, 2011 1:55 PM
To: nanog@nanog.org
Subject: Re: bfd-like mechanism for LANPHY connections between providers
On Wed, Mar 16, 2011 at 2:33 PM, Jensen Tyler <JTyler@fiberutilities.com> w=
rote:
> We have many switches between us and Level3 so we don't get a "interface =
down" to drop the session in the event of a failure.
This is often my topology as well. I am satisfied with BGP's
mechanism and default timers, and have been for many years. The
reason for this is quite simple: failures are relatively rare, my
convergence time to a good state is largely bounded by CPU, and I do
not consider a slightly improved convergence time to be worth an
a-typical configuration. Case in point, Richard says that none of his
customers have requested such configuration to date; and you indicate
that Level3 will provision BFD only if you use a certain vendor and
this is handled outside of their normal provisioning process.
For an IXP LAN interface and associated BGP neighbors, I see much more
advantage. I imagine this will become common practice for IXP peering
sessions long before it is typical to use BFD on
customer/transit-provider BGP sessions.
--=20
Jeff S Wheeler <jsw@inconcepts.biz>
Sr Network Operator=A0 /=A0 Innovative Network Concepts
