GRE forwarding on ASR9K

[Yang]

Is there a document on ASR9K tunnel traffic forwarding? 

some example questions

• Does GRE encapsulation always happen on egress NP? or an NP is assigned for each tunnel?
• Is GRE decapsulation and ingress lookup done in the same NP run?
• GRE encapsulation/decapsulation performance?
• meaning of GRE related counters GRE_ING_DECAP_P2_PROT_UNSUPPORTED, GRE_ING_DECAP_PRS_P2?

[Sudhir Kumar]

GRE_ING_DECAP_P2_PROT_UNSUPPORTED - this indicates GRE decapsulation header protocol value is not supported, frame gets dropped.

GRE_ING_DECAP_PRS_P2 - Frames entering GRE decapsulation 2nd pass processing on ingress NP

Thx
Sudhir 

[Aleksandar Vidakovic]

yes, GRE enccapsulation is an egress NP operation.

GRE decapsulation requires one more pass through the ingress NP.

Any performance test results are very much dependent on the specific test scenario because there are many factors that influence the performance (what other features are configured, traffic pattern, etc.). However, based on the fact that one more pass is required on decapsulation, this already gives you some indication of the performance impact.

hope this helps,

/Aleksandar