Configuring Weighted Random Early Detection - Cisco ASR 9000 Series Configuration Manual

Configuring Modular QoS Congestion Avoidance
Command or Action
Step 9
interface type interface-path-id
Example:
RP/0/RSP0/CPU0:router(config)# interface TenGigE
0/2/0/0
Step 10
service-policy {input | output} policy-map
Example:
RP/0/RSP0/CPU0:router(config-if)# service-policy
output policy1
Step 11 commit

Configuring Weighted Random Early Detection

WRED drops packets selectively based on any specified criteria, such as CoS, DSCP, EXP, discard-class, or
precedence . WRED uses these matching criteria to determine how to treat different types of traffic.
Configure WRED using the random-detect command and different CoS, DSCP, EXP, and discard-class
values. The value can be range or a list of values that are valid for that field. You can also use minimum and
maximum queue thresholds to determine the dropping point.
When a packet arrives, the following actions occur:
• If the queue size is less than the minimum queue threshold, the arriving packet is queued.
• If the queue size is between the minimum queue threshold for that type of traffic and the maximum
• If the queue size is greater than the maximum threshold, the packet is dropped.
Restrictions
When configuring the random-detect dscp command, you must configure one of the following commands:
shape average, bandwidth, and bandwidth remaining.
The Cisco ASR 9000 Series ATM SPA supports only time-based WRED thresholds. Therefore, if you
Note
try to configure the WRED threshold using the random-detect default command with bytes or packet as
the threshold units, the "Unsupported WRED unit on ATM interface" error occurs.
Only two minimum and maximum thresholds (each with different match criteria) can be configured per class.
threshold for the interface, the packet is either dropped or queued, depending on the packet drop
probability for that type of traffic.
Cisco ASR 9000 Series Aggregation Services Router Modular Quality of Service Configuration Guide, Release 6.1.x
Configuring Weighted Random Early Detection
Purpose
Enters the configuration mode and configures an
interface.
Attaches a policy map to an input or output interface to
be used as the service policy for that interface. In this
example, the traffic policy evaluates all traffic leaving
that interface.
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