How to make sure, that traffic got scheduled into particular class (control, service, bulk)?

  • 15 February 2017
  • 2 replies

Userlevel 1
According to, traffic can be scheduled in three different classes.

My question is - are there any tools, that can help verify, that particular traffic is scheduled per configuration?

For example, I want to make sure, that if I configure dscp 10 for service class - such traffic will be scheduled accordingly.

Thank you.


2 replies

Userlevel 5
Sounds like you're looking for a way to evaluate whether the DSCP value was scheduled to the correct ASIC-internal class of service. If this is the case, the answer would depend on the specific ASIC in question. There are no externally visible counters which are replicated into the Linux Kernel which contain that information. The only way to obtain the information would be to query the ASIC directly. Cumulus does not generally release commands to interact with the ASIC directly as they are numerous, asic-specific, incredibly verbose, can interfere with the flow of traffic through switch, and can have HORRIBLE side effects if mis-typed or otherwise mis-used. If you suspect that something is not being scheduled correctly I recommend opening a support case for more specific evaluation for your switch.
Userlevel 1
Eric, thank you for your comment.
My idea was to get some way to verify correctness of QoS configuration (for example, to see, that if I generate traffic with high priority, then corresponding queue counters are increasing). And, to demonstrate to the customer, that DC switches behave as expected, otherwise this switch looks more like black box from QoS standpoint.