QoS:"show interfaces" not showing packet drop but "show policy-map interface" do

[martin.bernier2]

Hi,

With LLQ+CBWFQ configured on an interface i can see tail packet drop using the command "Show policy-map interface X".  I'm wondering why in cannot see the same information about these packets drop with the "show interfaces X" command ?  Is the show interfaces only show information about tx-ring and is not related to layer 3 processor (software buffer) ?

This is basic question but i could not find info about this on CCO.

Regards,

[Frederic Vanderbecq]

Hello,

the drop counter under show interface should show you a collection of all the drops occurring on that subinterface. So, the drops seen under a service-policy should reflect under show interface as well.

Can you please tell me which router you are using, what is its software version, what type of module/port adapter is configured with the service-policy and the configuration used ?

Fred

[Mathias Garcia]

I think your are correct in your assumption that the dropped packets don't show up on the interface due to being dropped before entering the hardware queue. But I haven't really researched the issue, but its what makes sense to me and what I seem to recall from reading about it.

[martin.bernier2]

Thank you,

The device is a 3400ME with version 12.2(25)SEG1

The interface used is a gigabit interface with standard LLQ:

policy-map LLQ_POLICY
  class PQ
     priority
  class CLASS_HIGH
    bandwidth remaining percent 50

   class CLASS_MEDIUM
    bandwidth remaining percent 30
   class class-default
    bandwidth remaining percent 20
!
policy-map LLQ
  class class-default
  shape average 100000000
   service-policy LLQ_POLICY

!

interface GigabitEthernet0/1
service-policy output LLQ

!

Thank you for your helps...