Add subinterface egress VLAN filter drop counter

[ostromart]

This change introduces a new subinterface-level operational state counter 'out-vlan-filter-discards' to track packet drops caused by egress VLAN filtering mismatch. Version bumped to 3.9.0 in openconfig-interfaces.yang.

Change-Id: I9a11ff67688e8aec8f3d8eb08ef05220bff44040

Change Scope

• Description: This PR introduces a new subinterface-level operational state counter out-vlan-filter-discards to openconfig-interfaces.yang to track packets dropped due to VLAN egress filtering being enabled on the subinterface where the packet's VLAN tag did not match the allowed VLANs.
• Backwards Compatibility: This change is fully backward compatible as it only adds a new operational state leaf counter to an existing grouping.

Use case

This counter is designed for production network debugging. Silent packet drops are difficult to diagnose in live networks, so introducing granular drop counters like this one helps network operators to pinpoint and root cause issues. Unlike other counters (e.g packet drops), this counter indicates a configuration or programming error so if would not be seen as increasing during normal operation and would indicate that the system is not functioning as intended.

Platform Implementations

This counter is part of the Generic SAI Debug Counters spec, see also header file.

Google network switches implement egress VLAN filter drop counters to track packet dispatches that violate allowed VLAN criteria.

Tree View

 module: openconfig-interfaces
   +--rw interfaces
      +--rw interface* [name]
...
        +--rw subinterfaces
           +--rw subinterface* [index]
              +--rw index     -> ../config/index
              +--rw config
              |  +--rw index?         uint32
              |  +--rw description?   string
              |  +--rw enabled?       boolean
              +--ro state
                 +--ro index?          uint32
                 +--ro description?    string
                 +--ro enabled?        boolean
                 +--ro name?           string
                 +--ro ifindex?        uint32
                 +--ro admin-status    enumeration
                 +--ro oper-status     enumeration
                 +--ro last-change?    oc-types:timeticks64
                 +--ro logical?        boolean
                 +--ro management?     boolean
                 +--ro cpu?            boolean
                 +--ro counters
                    +--ro in-octets?                  oc-yang:counter64
                    +--ro in-pkts?                    oc-yang:counter64
                    +--ro in-unicast-pkts?            oc-yang:counter64
                    +--ro in-broadcast-pkts?          oc-yang:counter64
                    +--ro in-multicast-pkts?          oc-yang:counter64
                    +--ro in-errors?                  oc-yang:counter64
                    +--ro in-discards?                oc-yang:counter64
                    +--ro out-octets?                 oc-yang:counter64
                    +--ro out-pkts?                   oc-yang:counter64
                    +--ro out-unicast-pkts?           oc-yang:counter64
                    +--ro out-broadcast-pkts?         oc-yang:counter64
                    +--ro out-multicast-pkts?         oc-yang:counter64
                    +--ro out-discards?               oc-yang:counter64
                    +--ro out-errors?                 oc-yang:counter64
                    +--ro last-clear?                 oc-types:timeticks64
                    x--ro in-unknown-protos?          oc-yang:counter64
                    x--ro in-fcs-errors?              oc-yang:counter64
                    x--ro carrier-transitions?        oc-yang:counter64
+                   +--ro out-vlan-filter-discards?   oc-yang:counter64

[gemini-code-assist]

Code Review

This pull request updates the openconfig-interfaces YANG module to version 3.9.0, introducing a new subinterface operational egress VLAN filter drop counter (out-vlan-filter-discards). The feedback suggests enhancing the description of this new counter to include the standard OpenConfig statement regarding counter discontinuities, ensuring consistency with other counters in the module.

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[navaneethyv]

review June 2 :

Request to elaborate on the use case and share the link to the SAI APIs and the vendor implementations if any in the PR.

[ostromart]

I've updated the PR description as requested, PTAL @navaneethyv

[dplore]

/gcbrun

[OpenConfigBot]

No major YANG version changes in commit a1eb4f4