Re: MPLS TE

[harbor235 <harbor235 () gmail com>]

I am also looking at FRR which uses a backup tunnel for fast convergence. I
did however not think
about the dynamic nature of the tunnel and the potential for
reestablishment.


Mike

On Fri, Nov 4, 2011 at 12:49 PM, Vitkovsky, Adam <avitkovsky () emea att com>wrote:

> Hello Mike,
> What exactly do you mean by primary and backup please?
> As the tunnel "mpls traffic-eng priority" cmd simply only specifies the
> setup and hold priorities
> (you'd use those when there are tunnels carrying low priority traffic
> filling up the available TE BW -and you need to setup a tunnel carrying
> voice through that link -because the primary link failed -the higher setup
> priority of the voice tunnel would knock down some of the scavenger tunnels
> with lower 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
> failed 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
>
>
> -----Original Message-----
> From: harbor235 [mailto:harbor235 () gmail com]
> 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