3com 8807 Reference Guide

In the case of network congestion, the switch drops packets to release system 
resources. And then no packets are put into long-delay queues. The following two 
drop modes are available:

■

Tail drop mode: different queues (red, yellow and green) are allocated with 
different drop thresholds. When these thresholds are exceeded respectively, 
excessive packets will be dropped.

■

WRED drop mode: Drop precedence is taken into account in drop action. 
When only min-thresholds of red, yellow and green packets are exceeded, 
packets between min-thresholds and max-thresholds are dropped randomly at 
a given slope. But when max-thresholds of red, yellow and green packets are 
exceeded, all excessive packets will be dropped.

# Set the port Ethernet3/1/1 in WRED drop mode; import WRED 0 as the 
threshold.

<SW8800> system-view

 

System View: return to User View with Ctrl+Z. 

 

[SW8800]interface Ethernet3/1/1

 

[3Com-Ethernet3/1/1] drop-mode wred 0 

dscp dscp-list : dscp-value exp-value cos-value local-precedence-value 
drop-precedence

undo dscp dscp-list

Conform level view

dscp-list: Original DSCP value, which can be a single value or several values, in the 
range of 0 to 63. For example, you can type single DSCP value "46", or DSCP 
values "0 8 10 16" (space is required between two values).

dscp-value: Modified DSCP value, in the range of 0 to 63.

exp-value: Modified EXP value, in the range of 0 to 7. EXP is MPLS priority of MPLS 
packets.

cos-value: Modified 802.1p priority value, in the range of 0 to 7

local-precedence-value: Modified local precedence value, in the range of 0 to 7.

drop-precedence: Modified drop precedence value, in the range of 0 to 2.

Use the dscp command to configure the "DSCP + Conform-level -> 
Service-parameter" mapping table of current conform level.

Use the undo dscp command to restore default configuration of the "DSCP + 
Conform-level -> Service- parameter" mapping table.