Enterasys Networks D-Series - Manual (Page 349)

Enterasys D-Series CLI Reference 12-1
12
Port Priority and Rate Limiting Configuration
This chapter describes the Port Priority and Rate Limiting set of commands and how to use them.
Port Priority Configuration Summary
The D‐Series device 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 queueing
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 assign them to transmit queues 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 traffic on a per port/priority basis.
Configuring Port Priority
Purpose
To view or configure port priority characteristics as follows:
• Display or change the port default Class‐of Service (CoS) transmit priority (0 through 7) of
each port for frames that are received (ingress) without priority information in their tag
header.
For information about... Refer to page...
Port Priority Configuration Summary 12-1
Configuring Port Priority 12-1
Configuring Priority to Transmit Queue Mapping 12-4
Configuring Quality of Service (QoS) 12-6
Configuring Port Traffic Rate Limiting 12-10
Note: When CoS override is enabled using the set policy profile command as described in “ set
policy profile ” on page 11-3, CoS-based classification rules will take precedence over priority
settings configured with the set port priority command described in this section.