QoS Questions: WRED & Queuing

[AJ Cruz]

When I do a "sh queueing interface" on a catalyst switch, I see the queueing strategy as weighted round-robin, but when I do a "sh int" for the same interface the queuing strategy says "fifo." Why is that?

Also, is there a command to tell me definitievly what the drop mechanism is for a given interface or queue? Or is it as simple as if I see no random detect commands I can assume its tail drop?

Thanks!

[Mohamed Sobair]

Hi,

The first command show the Software Queueing Startegy configured on the Interface, The Second command indicates the Hardware Queue strategy which is (FIFO), and the Hardware Queue is always (FIFO).

There is no special command for that,

Here As I recall From CCIE Certification Guide:

(If a queue packet is full, Cisco IOS software has no place to put extra packet, and the packet starts to be dropped. This phenomena (behaviour) is called (Tail drop behaviour).

So, you should  Assume all packets is discarded according to the FIFO, unless Queuing is applied to mitigate this behaviour.

HTH

Mohamed