[146126] in North American Network Operators' Group
RE: MPLS TE
daemon@ATHENA.MIT.EDU (Vitkovsky, Adam)
Fri Nov 4 12:50:39 2011
From: "Vitkovsky, Adam" <avitkovsky@emea.att.com>
To: harbor235 <harbor235@gmail.com>, NANOG list <nanog@nanog.org>
Date: Fri, 4 Nov 2011 17:49:31 +0100
In-Reply-To: <CAB_zYdKv0v13-8eezR8VRwCJ=Myxh2prvr-odW-X-U6Lp027kQ@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Hello Mike,
What exactly do you mean by primary and backup please?
As the tunnel "mpls traffic-eng priority" cmd simply only specifies the set=
up and hold priorities=20
(you'd use those when there are tunnels carrying low priority traffic filli=
ng up the available TE BW -and you need to setup a tunnel carrying voice th=
rough that link -because the primary link failed -the higher setup priority=
of the voice tunnel would knock down some of the scavenger tunnels with lo=
wer hold priority)
Now I'm not sure but I guess you can't have one tunnel act as backup for a =
specific te-tunnel
Though you can configure a te-tunnel to act as a backup for a link
Since one of your tunnels is dynamic it can be re-established around the fa=
iled link
Though which tunnel is going to be used to forward traffic is based on how =
you instruct the trafic to use one of the tunnes as primary path
adam
=20
-----Original Message-----
From: harbor235 [mailto:harbor235@gmail.com]=20
Sent: Friday, November 04, 2011 5:10 PM
To: NANOG list
Subject: MPLS TE
TE lab testing flushing out how TE works, configured a primary and backup
tunnel between PEs, both directions.
Primary is dynamic and backup is explicit, initially priorities were the
same, I then choose
to make one tunnel preferred over the other adjusting the priorities, I
choose the tunnel that was backup
to become primary to watch the traffic shift. (primary path was P1-P2-P3,
backup path P1-P3). However,
the traffic did not shift, a manual shut on a P3-P2 interface made the
traffic shift, reintroduction
kept the traffic on P1-P3, then a "mpls traffic reoptimize" moved the
traffic back to P1-P2-P3.
Obviously the preferred MPLS tunnel is still P1-P2-P3 even though I
configured "tunnel mpls traffic-eng priority 1 1"
on P1-P3 and "tunnel mpls traffic-eng priority 7 7" on P1-P2-P3. What am I
missing here?
My setup:
CE-----PE-----P1----------P3-------PE----CE
\ /
\ /
P2
Mike
