Port Priority

The S- K- and 7100-Series devices supports Class of Service (CoS), which allows you to assign mission-critical data to higher priority through the device by delaying less critical traffic during periods of congestion. The higher priority traffic through the device is serviced first before lower priority traffic. The Class of Service capability of the device is implemented by a priority queuing mechanism. Class of Service is based on the IEEE 802.1D (802.1p) standard specification, and allows you to define eight priorities (0 through 7) and, depending on port type, up to 16 transmit queues (0-15) of traffic for each port.

A priority 0 through 7 can be set on each port, with 0 being the lowest priority. A port receiving a frame without priority information in its tag header is assigned a priority according to the default priority setting on the port. For example, if the priority of a port is set to 4, the frames received through that port without a priority indicated in their tag header are classified as a priority 4 and transmitted according to that priority.

In addition, the device‘s rate limiting capabilities allow you to further prioritize traffic by limiting the rate of inbound or outbound traffic on a per port/priority basis.

Note

When CoS override is enabled using the set policy profile command as described in the “Policy Profile Commands” section of the S-, K-, and 7100 Series CLI Reference Guide, CoS-based classification rules will take precedence over priority settings configured with the set port priority command described in this section.

Use the set port priority command in any command mode to set the port priority for the specified ports.

The following example sets the port priority for port ge.1.1 to 4:

System(rw)->set port priority ge.1.1 4
System(rw)->show port priority ge.1.1
ge.1.1 is set to 4