QoS Queues Window

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.

Catalyst 2950 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.

Bandwidth

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.

CoS-Queue ID

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:

  1. Select one or more rows.
    Click in a row to select only one row.
    Press Shift and click in contiguous rows to select contiguous rows.
    Press Ctrl and click in noncontiguous rows to select noncontiguous rows.
    Click Select All to select all the rows.
  2. Enter a queue ID in the field to the right of the Set Selected button.
  3. Click Set Selected. The queue IDs in all the selected rows change to the queue ID you entered.

If you later want all the entries to revert to the default mappings, click Set Defaults.

Catalyst 3550 Switches

On Catalyst 3550 switches, you can configure egress queues on individual interfaces. Follow these steps to select the interfaces and configure the queues:

  1. Select a device from the Host Name list.
  2. Select one or more interfaces from the Interfaces list.
    You can select consecutive interfaces by holding the Shift key down as you click.
    You can select nonconsecutive interfaces by holding the Ctrl key down as you click.
    You can select only one type of interface at a time (Fast Ethernet or Gigabit Ethernet).
  3. Click Configure and use the Configure QoS Queues window to configure the attributes of the egress queues.
  4. Click OK in this window when you finish with the Configure QoS Queues window.