[Bier] Comments on draft-ietf-bier-pmmm-oam-04

[Suneesh <[e-mail]>]

Hi Greg,

I have following comments on PMMM draft, please share your thoughts.

Q1. Can you please share how the draft is viewed as a hybrid model?

Ref: Section-3:

<snip>
   the marking method in BIER layer can be viewed as the example of the
   hybrid performance measurement method
</snip>


Q2. Can you please define what is meant by sub-flows
   a). Is the sub-flow set of flows on which marking method is applied OR
   b). sub-flow-1 with say marking 0 and sub flow-2 with say marking 1 OR
   c). Being a hybrid model, draft proposes to duplicate the multicast
stream which is having marking and treated those as sub-flows?

Ref: Section-4: Theory of Operation
<snip>
   Using the marking method a BFR creates distinct sub-flows in the
   particular multicast traffic over BIER layer
</snip>


Q3. Is there any recommended values for 'number of packets' or/and 'time
duration' for alternate marking method
    a). Just to know what is recommended to avoid say number of
packets/time duration = 1

Q4. Lets say that the nodes is like A->B->C->D->F->G->H->I, the segment of
interest is B->C->D for performance measurement
  a). Does the alternate marking values will clear from node D onwards?
  b). If not, what is recommended if we wish to measure between G->H->I

Ref: Section-4: Theory of Operation

<snip>
  Any combination of markings, Loss and/or Delay, can be applied to a
multicast flow by
  any Bit Forwarding Router (BFR) at either ingress or egress point to
   perform node, link, segment or end-to-end measurement to detect
   performance degradation defect and localize it efficiently.
</snip>

Q5. Can we somewhere capture that 'proto' field of BIER header should not
be "OAM request/reply", though we are using OAM bits in header.

<snip>
   The OAM field MUST be used only
   for the performance measurement of data traffic in BIER layer.
</snip>


Regards,
Suneesh