VOQ statistics collection for subinterfaces

The qos interfaces interface voq-statistics command allows you to explicitly configure VOQ statistics collection on a subinterface. When voq-statistics is set to true for a subinterface, SR Linux attempts to allocate VOQ statistics collection resources from the global VOQ statistics resource pool to that subinterface. This feature allows you to prevent VOQ statistics resource exhaustion by allocating VOQ statistics resources to those subinterfaces that require them most.

This command is also supported to enable VOQ statistics per subinterface. The only difference for subinterface queuing is that the default setting is false, while for interface queuing the default setting is true.

VOQ statistics collection resources are dependent on allocation of flexible counter banks. For more information see "Flexible counter bank allocation" in the SR Linux Configuration Basics Guide.

BUM traffic handling

BUM traffic on 7250 IXR Gen 3 platforms is always replicated with a two-pass mechanism. In the first pass traffic is sent towards the fabric and then the fabric replicates packets to the eligible egress slots. In the second pass, traffic is replicated on the egress device for local subinterfaces. As a result, the ingress VOQ statistics increment on the egress slot VOQ.