openconfig
Clarify meaning of ecn-marked-pkts and ecn-marked-octets
This PR https://github.com/openconfig/public/pull/960, introduced ECN counters to OpenConfig with two separate counters for different implementations.
The ecn-selected-pkt and ecn-selected-octets matches the Arista implementation.
The PR also introduced ecn-marked-pkts and ecn-marked-octets and cited Cisco IOS XR as an example of an implementation that implements these. However, Cisco IOS XR does not implement the counters as defined in that PR. More specifically, it will increment the marked packet if ECN is supported for the packet and it experiences congestion, regardless of whether it previously experienced congestion.
I.e., it changes one of the rows in the table for the PR from:
FROM:
| ingressing packets ECN bits | queue utilization | ecn-selected-pkts, ecn-selected-octets | ecn-marked-pkts , ecn-marked-octets |
|---|---|---|---|
| CE (11) | above RED max-treshold | increments | not increments |
TO:
| ingressing packets ECN bits | queue utilization | ecn-selected-pkts, ecn-selected-octets | ecn-marked-pkts , ecn-marked-octets |
|---|---|---|---|
| CE (11) | above RED max-treshold | increments | increments |
This issue (and the associated PR) is to help determine whether other vendors implement the ecn-marked-* counts as currently specified, or whether the definition can be updated to match IOS XR, if this is the only implementation.
