This window appears when you choose Device > QoS > Queues on the menu bar. You can also click here to launch it. Use it to configure egress queues on Catalyst 2950 switches and on Catalyst 3550 switches.
On Catalyst 2950 switches, you configure egress queues for the entire device. The window has two tabs for this purpose: Bandwidth and CoS-Queue ID.
This tab shows whether you are using a weighted-round-robin (WRR) or strict priority queuing algorithm. If you are using WRR, the tab also shows, in relative terms, how much bandwidth that you are allotting to each queue from the bandwidth available to all four queues.
By default, the Enable WRR box is unchecked, meaning that the strict priority algorithm is in use. Queue 4 is always serviced first; Queue 3 is serviced when Queue 4 is empty; Queue 2 is serviced when Queues 3 and 4 are empty; and Queue 1 is serviced when Queues 2, 3, and 4 are empty.
If you check Enable WRR, you can specify a number from 1 to 255 in the field beside each queue ID. The relative size differences in the numbers determine the relative differences in bandwidth allotments. For example, if the numbers top to bottom were 1, 2, 3, and 4, Queue 4 would have four times the bandwidth of Queue 1, twice the bandwidth of Queue 2, and one-and-a-third times the bandwidth of Queue 3. To revert to the default bandwidths at any time, click Set Defaults.
This tab contains a table that maps CoS values to queue IDs; it directs outbound packets with certain CoS values to the mapped queues.
To change the default CoS-queue ID mappings:
If you later want all the entries to revert to the default mappings, click Set Defaults.
On Catalyst 3550 switches, you can configure egress queues on individual interfaces. Follow these steps to select the interfaces and configure the queues: