Traffic Mirroring; Qos Configuration; Configuring Priority Trust Mode - 3Com E4500-24 Cli Configuration Manual

In WRED algorithm, an upper limit and a lower limit are set for each queue, and the packets in a queue
are processed as follows.
When the current queue length is smaller than the lower limit, no packet is dropped;
When the queue length exceeds the upper limit, all the newly received packets are dropped;
When the queue length is between the lower limit and the upper limit, the newly received packets
are dropped at random. The longer the queue, the more likely the newly received packets may be
dropped. However, a maximum drop probability exists.
In WRED, random numbers are generated to determine the packets to be dropped. As the dropping
policy is determined by IP precedence, packets with lower precedence are more likely to be dropped.
WRED prevents global TCP session synchronization. It enables other TCP sessions to be free of a TCP
session slowed down because of its packets being dropped. In this way, TCP sessions can operate in
different rates in any case and the link bandwidth can be fully utilized.

Traffic mirroring

Traffic mirroring identifies traffic using ACLs and duplicates the matched packets to the destination
mirroring port or CPU depending on your configuration. For information about port mirroring, refer to the
Mirroring module of this manual.

QoS Configuration

Complete the following tasks to configure QoS:

Configuring Priority Trust Mode

Configuring the Mapping between 802.1p
Priority and Local Precedence
Setting the Priority of Protocol Packets
Marking Packet Priority
Configuring Traffic Policing
Configuring Line Rate
Configuring VLAN Mapping
Configuring Queue Scheduling
Configuring WRED
Configuring Traffic Mirroring
Configuring Priority Trust Mode
Refer to section
Configuration prerequisites
The priority trust mode to be adopted has been determined.
The port where priority trust mode is to be configured has been determined.
The port priority value has been determined.
Task
Priority Trust Mode for introduction to priority trust mode.
Optional
Optional
Optional
Optional
Optional
Optional
Optional
Optional
Optional
Optional
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Remarks