SR-TE RSVP-TE Stitching
Load sr-te.rsvp-te.stitching.init.cfg.
There is an RSVP-TE tunnel on R3 taking the path R3-R4-R6-R5. On R1, configure an SR-TE policy that uses R7 as an endpoint and is steered into the RSVP-TE tunnel on R3 without using autoroute announce on R3 or static routes.
Answer
Explanation
Allocating a BSID to an RSVP-TE tunnel allows it to be used by SR-TE policies. This can be a way to stitch an SR-TE path over a core which does not support SR-TE, and only supports RSVP-TE.
It is very straight forward to allocate a BSID to a TE tunnel, simply using the below command:
Alternatively, you can use the following command, which will allocate a BSID for the TE tunnel from the dynamic range.
On R3, we can see that an LFIB entry was created for lab 4005, with outgoing instruction “pop and forward out TE tunnel.”
This allows R1 to use the BSID label 4005 in a local SR-TE policy. As with any local SID, we first specify the target node, and then specify the local SID. Finally, we use R7’s prefix SID to get to the final destination.
R1 only validates the first label in the explicit path, so it doesn’t matter that R1 does not learn of label 4005 from some other means.
To test this out, R7 sets routes received from CE107 to have the color 10:
A traceroute from CE101 to CE107 shows that traffic is indeed being steered along the RSVP-TE path:
We can also test by examining the output counters on the TE tunnel on R3.
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