Traffic Engineering

[galo]

Mine is a lab environment. I just wanted to get some others experience with the dynamic path option for MPLS TE tunnels.

I had the MPLS-TE tunnels up up. IGP configured is OSPF. I went ahead and failed an interface along the path (pulled it out =)) in order to see if the dynamic path option would automatically reroute the tunnel since dynamic was configured as option 2 in the config. Needless to say dynamic path option appeared to do nothing.

BTW I did have RSVP and traffic engineering configured along a new path within the topology.

I have not configured Fast Reroute yet. I'm hoping OSPF reroutes my tunnel for me.

Cheers!

[Harold Ritter]

Can you post your configs. The tunnel path should be recalculated almost instantly if you indeed have a backup path.

Hope this helps,

[galo]

I didn't configure a b/u path. I enabled TE, RSVP, as well as the OSPF entensions along the topology assuming my second path option, "dyanmic" would reroute traffic on its own. I was disappointed to see this was not the case.

If what you are sayin is that the only way to reroute is via an explicitly defined backup path, than why does cisco include a dynamic option? Or is this command used in conjunction with something I may have missed?

command in question:

"tunnel mpls traffic-eng path-option 2 dynamic"

Cheers!

[Harold Ritter]

Sorry for the confusion. By backup path I meant backup path in the IGP. Configuring the dynamic option will cause the tunnel to follow the new IGP path in case of a failure.

Hope this helps,

[galo]

IGP configured is OSPF in a single area 0. Although the IGP recovered, as well as MPIBGP, and traffic was routing around the failed interface the tunnel never came back up.

This was my assumption but didn't work as expected:

"Configuring the dynamic option will cause the tunnel to follow the new IGP path in case of a failure."

BTW I'm using 12.2.24a.

[Harold Ritter · Accepted solution]

Do you have BW requirements configured on the tunnel? Is this requirement met by the redundant IGP path?

Try to remove the "tunnel mpls traffic-eng bandwidth"

and see if this solves your problem.

Hope this helps,

[galo]

Thanks for the suggestion; unfortunately, it didn't work. The path consists of all fastethernet interfaces on 7204 routers. Along the path I have the following configured:

Global:

mpls traffic-eng tunnels

interface:

tag-switching mtu 1526

tag-switching ip

ip rsvp bandwidth 1500 1500

all routers ospf config:

mpls traffic-eng router-id Loopback0

mpls traffic-eng area 0

BTW I removed the "tunnel mpls traffic-eng bandwidth 1500" from the tunnel interface as you recommended.

[galo]

After taking a closer look at what I posted I realized I missed mpls traffic-eng tunnels and only had configured for ip rsvp bandwidth 1500 1500 along the path. Needless to say the tunnels are back up now! So sorry for the long winded posting...

[Harold Ritter]

No problem. It always help to have another pair of eyes.