[bess] Inverse multi-layer OAM

[Greg Mirsky <[e-mail]>]

Hi Himanshu,

Thank you for the presentation of
draft-karboubi-spring-sidlist-optimized-cs-sr
<https://datatracker.ietf.org/doc/draft-karboubi-spring-sidlist-optimized-cs-sr/>.
If I understood your response to Ali correctly, the proposed mechanism is
expected to use more aggressive network failure detection than the link
layer. If that is correct, I have several questions about the multi-layer
OAM:

   - AFAIK link-layer failures are detected within 10 ms using a
   connectivity check mechanism (CCM of Y.1731 or a single-hop BFD) with a 3.3
   ms interval.
   - If the link failure is detectable within 10 ms, what detection time
   for the path, i.e., E2E connection failure detection, is suggested? What
   interval between test probes will be used in that case?
   - Furthermore, even if the path converges around the link failure before
   the local protection is deployed, the link failure will be detected, and
   the protection mechanism will be deployed despite the Orchestrator setting
   up its recovery path in the network. If that is correct, local defect
   detection and protection are unnecessary overheads. Would you agree?


Regards,

Greg