Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 499)

Configuring Random Early Discard
Consider the topics discussed below when configuring Random Early Discard (RED) mappings.
Understanding RED profiles
Consider the following when configuring RED.
• Up to four RED profiles can be applied to each port group. On the 48 x 10G line card, the port groups
consist of ports 1–8, 9–16, 17–24, 25–32, 33–40, and 41–48. On the 12x40G line card, the port
groups consist of ports 1–2, 3–4, 5–6, 7–8, 9–10, and 11–12.
• Trunk ports cannot share RED profiles with any other ports because the bandwidth for a trunk port
changes according to the number of active links in the trunk.
• When queue thresholds in a RED profile are configured by percentage, the switch maps this to a
total number of bytes as buffers allocated to a port depend on the port speed.
• A total of 384 RED profiles are supported per chassis.
Consider the following when using RED profiles for link aggregation (LAG) interfaces:
• RED profiles can be enabled on LAG interfaces. However, the profile is configured on the individual
member interfaces of the LAG.
• Because LAG members may belong to different port groups, one of the port groups may not have
enough resources available to support a new RED configuration for the member interface. In this
case, and error log will indicate that the RED application failed on the specific member interface.
When a new member is added to the port-channel, the same error may occur if the new member
belongs to an port groups with all resources used. To apply the RED profile on the failed member
interface, you must remove the RED configuration on other all interfaces in the port group so that
resources are available and remove or add the member interface to the LAG.
Configuring RED profiles
To configure an egress RED profile, perform the following steps from privileged EXEC mode.
1. Enter global configuration mode.
switch# configure terminal
2. Configure a RED profile. For the profile ID, 10 is used in this case. The min-threshold, max-threshold,
and drop-probability values are percentages.
switch(config)# qos red-profile 10 min-threshold 10 max-threshold 80 drop-
probability 80
3. Return to privileged EXEC mode.
switch(config)# end
4. Enter the copy command to save the running-config file to the startup-config file.
switch# copy running-config startup-config
Mapping a CoS priority to an RED profile on an interface
To map a CoS priority value for a port to the RED profile created under Understanding RED profiles on
page 499, perform the following steps from privileged EXEC mode.
1. Enter global configuration mode.
switch# configure terminal
2. Specify the Ethernet interface.
switch(config)# interface tengigabitethernet 1/2/2
3. Map the profile to use a CoS priority for a port. In the following example, CoS priority 3 is mapped to
RED profile ID 10.
switch(conf-if-te-1/2/2)# qos random-detect cos 3 red-profile-id 10
Configuring Random Early Discard
Network OS Administrator’s Guide 499
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