Can Traffic Engineering override route preferences?

[Yury Kudinov]

Hi Guys. Have been trying to figure out SDW TE weird behaviour.

Here is simplified topology, please note, I've simplified actual task heavily: Two sites (Site-A, Site-B), one cEdge on each site, with 2 transports between them: MPLS, Biz-internet. Both sites learn routes over MPLS with priority 500 and router over Internet with Priority 100.

The task is:

Configure communication between sites to prefer Internet transport first and fall back to MPLS, but do not touch route control policy.

The only available method I've found is to use Traffic Engineering, match any traffic and set local TLOC "Inernet". The problem that this approached worked for me only if routes learned over MPLS and Internet have equal metrics. If MPLS has higher priority (as in task description above), then attempts to override behaviour with setting local TLOC had unpredictable results.

[Octavian Szolga]

Hi Yury,

When deploying a Data Policy that sets a local TLOC for a specific destination or any destination, you're only controlling how to take off from the local site and not on what colour you're landing on.

Long story short, in order to influence TLOC selection in both ways, you have to apply the same policy on both cEdge routers (with a 'from service' direction).

If you simulate the flow, you should get predictable results.

BR,

Octavian

[Yury Kudinov]

Hi Octavian.

That's exact what I did. I've applied TE policy on both sides from service.

The problem that it worked perfectly as long as routes priority were equal over MPLS and Internet.

I had traffic behaving awesomely, failing back, recovering, no issues. As soon as my route priority was preferring MPLS, but TE on both sides were directing traffic to Internet, that didn't work.

I'll double check it now and comeback. Sincerely hope I missed something, it was very long day yesterday.