[161352] in North American Network Operators' Group
Re: internet routing table in a vrf
daemon@ATHENA.MIT.EDU (Phil Bedard)
Fri Mar 8 18:09:21 2013
In-Reply-To: <20130308225532.GA18175@pob.ytti.fi>
From: Phil Bedard <bedard.phil@gmail.com>
Date: Fri, 8 Mar 2013 18:09:08 -0500
To: Saku Ytti <saku@ytti.fi>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Mar 8, 2013, at 5:55 PM, Saku Ytti <saku@ytti.fi> wrote:
> On (2013-03-08 18:17 +0000), Matt Newsom wrote:
>=20
>> If you run PIC and hide the next hop information between a loopback w=
hich is what will happen in a vpn environment
>=20
> Typical SP network has next-hop-self in INET BGP, and does not carry
> edge-links in IGP. You don't want to have lot of prefixes in IGP.
>=20
>> If the remote PE has PIC running he can bounce that traffic back to his b=
ackup path via another PE.
>=20
> PIC merely makes sure that FIB is hierarchical and it guarantees all
> prefixes sharing next-hop converge at same time.
> Local-repair can be done with or without PIC, as it just means you have
> local information how to deliver frame to alternate destination without
> expectation of convergence.
Unfortunately Cisco made things confusing by naming their "BGP FRR" feature "=
BGP PIC Edge."
>=20
>> There will be some percentage of your traffic that will then form a trans=
ient micro loop though because that remote PE will have his primary path thr=
ough the failed link due to shortest as path length etc
>=20
> Only if egress PE does IP lookup, which is typically does not do
> (per-prefix or per-ce, default config in 7600, JunOS, IOS-XR) as egress PE=
> label adjacency entry has egress rewrite information.
> The faulted edge PE can local-repair and get frame delivered without havin=
g
> to wait for BGP to converge for the customer. Transient loop can occur if
> both of the edges have faulted.
>=20
> --=20
> ++ytti
>=20
