priority queuing

[tzuuyi]

I tried to set up priority queuing (PQ) to allow one traffic prioritized over others on router 1600. For some reason, it seemed this actually slow down the traffic I prioritized. Does anyone know that whether this type of router supports PQ or not ? Or PQ is only for specific application (like non-high-speed case)?

[MickPhelps]

Cisco suggests that you only use Priority, Weighted Fair, or Custom Queuing on interfaces with T1 or lower speeds for exactly that reason.

What speed is the interface you're trying to queue?

I'm not sure if the 1600 supports CAR, but it may be a more appropriate solution.

Mick.

[seilsz]

You might also check the queue statistics to see if you are dropping packets. By default, the high queue in PQ only has a depth of 20 packets.

[tzuuyi]

Mick,

We have this interface of speed 10Mbs. I guess that's what happened. However, 1600 series router we purchased came with these interfaces and the manual claims of supporting the PQ. If Cisco knows router 1600 is not suitable for PQ, why claim otherwise ?

Jim

[cketan]

"show queueing priority" should shed some more light on your strange problem. Check the utilization of the WAN link. If it is more than 805% then queuing wont help. Be sure that the traffic you prioritized is correctly using the protocol set to HIGH in the priority-list command. If this is correct, then try setting the max no. of packets (high-limit) from default of 20 to say 40 temporarily for observation.

Regards...Ketan Chaudhari, CCSA, CCNP, MCSE