Clarify meaning of ecn-marked-pkts and ecn-marked-octets

[rgwilton]

Change Scope

• Clarify meaning of ecn-marked-pkts and ecn-marked-octets
• Not backwards compatible, but unclear if there are any existing implementations.
• See Clarify meaning of ecn-marked-pkts and ecn-marked-octets #1298 for more details

Platform Implementations

• Implementation A: Cisco IOS XR

This PR is intended to act as a discussion point to determine whether this change is acceptable.

[LimeHat]

Not backwards compatible, but unclear if there are any existing implementations.

we (Nokia) do have an implementation.

[rgwilton]

Not backwards compatible, but unclear if there are any existing implementations.

we (Nokia) do have an implementation.

Do you know if your implementation exactly matches the specification. I.e., you only increase the counter if the packet is newly marked and wasn't previously marked?

[LimeHat]

yes, it is implemented as currently defined; ce(11) marked packets do not increment the counters

[pandurangan-arista]

As indicated in PR #1298 (comment)

Starting from 4.34.0F, Arista platforms DCS-7280R, DCS-7280R2, DCS-7500R, DCS-7500R2, DCS-7280R3, DCS-7500R3 and DCS-7800R implement support for counting (only exposed via CLI as of now) as defined in PR #960 originally. We are planning to follow this up with corresponding openconfig changes, so that it matches PR #960 specification.

It looks more appropriate to NOT count packets that have previously experienced congestion and changing the specification as proposed in this PR seems regressive.