Resilience Configuration on ietf-eth-tran-service

[italobusi]

A few placeholder on resilience configuration will be added into the current ietf-eth-tran-service, which will appear in draft-zheng-ccamp-client-signal-yang-04. Attributes to be configure include the WTR, hold-off-timer, revert/non-revert and so on...

An open issue would be where to configure the resilience attributes. A few potential places include:

Resilience on the access port: LAG/DRNI/MC-LAG information;
Resilience on the service instance, usually shown on Pseudowire;
Resilience on the L2 tunnel, which is MPLS-TP tunnel;
Resilience on the L1 tunnel, which is OTN/SDH tunnel;
Currently, item 4 is supported by te-tunnel model.

In practice, 2 and 3 are usually not implemented together. On the perspective of service protection, feasible configuration would be 1+2+4 or 1+3+4(all optional) .

Will need to add the resilience information for 1/2/3 in ietf-eth-tran-service.

Imported from: haomianzheng/IETF-ACTN-YANG-Model#31