1-24
Cisco 10000 Series Router Quality of Service Configuration Guide
OL-7433-09
Chapter 1 Quality of Service Overview
QoS Features, Commands, and Changes
Cisco IOS Release:
Release 12.2(31)SB2
Description:
This feature was introduced on the PRE3.
Random Early Detection Feature
Cisco IOS Release:
12.0(17)SL
Description:
The random early detection (RED) feature was introduced on the PRE1 to enable the
configuration of a packet drop policy. RED is a mechanism that is used to control congestion by
randomly discarding packets before a queue reaches its queue limit.
Cisco IOS Release:
Release 12.0(22)S
Description:
This feature
was enhanced to include RED based on a differentiated services code point
(DSCP). For the PRE1, DSCP-based RED supports one default drop profile per class, three assured
forwarding (AF) drop profiles per class, and four non-AF drop profiles per policy map.
Cisco IOS Release:
Release 12.0(25)SX
Description:
This feature was enhanced to allow you to simultaneously configure a packet drop policy
for a class queue (using the
random-detect
command) and the size of the class queue (using the
queue-limit
command).
Cisco IOS Release:
Release 12.2(16)BX
Description:
This feature was introduced on the PRE2.
Cisco IOS Release:
Release 12.2(28)SB
Description:
This feature was integrated in Cisco IOS Release 12.2(28)SB.
Cisco IOS Release:
Release 12.2(31)SB2
Description:
This feature was introduced on the PRE3.
Weighted Random Early Detection Feature
Cisco IOS Release:
Release 12.0(17)SL
Description:
The weighted random early detection (WRED) feature was introduced on the PRE1 to
provide preferential handling of higher priority packets. WRED allows drop policies based on a
differentiated services code point (DSCP) and IP precedence levels.
Cisco IOS Release:
Release 12.0(22)S
Description:
This feature
was enhanced to include WRED based on a differentiated services code point
(DSCP).
Cisco IOS Release:
Release 12.0(25)SX
Description:
This feature was enhanced to allow you to simultaneously configure a packet drop policy
for a class queue (using the
random-detect
command) and the size of the class queue (using the
queue-limit
command).