FTOS Configuration Guide for the C-Series - Force10 Networks

WRED uses a profile to specify minimum and maximum threshold values. The minimum threshold is the
allotted buffer space for specified traffic, for example 1000KB on egress. If the 1000KB is consumed,
packets will be dropped randomly at an exponential rate until the maximum threshold is reached (Figure );
this is the “early detection” part of WRED. If the maximum threshold—2000KB, for example—is reached,
then all incoming packets are dropped until less than 2000KB of buffer space is consumed by the specified
traffic .
Figure 405 Packet Drop Rate for WREDl
You can create a custom WRED profile or use on of the five pre-defined profiles listed in Table 57.
Create WRED Profiles
To create a WRED profile:
All Pckts
Packet Drop Rate
0 Pckts
0KB
Allotted Space
Min Max
Buffer Space
Table 57 Pre-defined WRED Profiles
Default Profile
Name
Minimum
Threshold
Maximum
Threshold
wred_drop 0 0
wred_ge_y 1024 2048
wred_ge_g 2048 4096
wred_teng_y 4096 8192
wred_teng_g 8192 16384
1. Create a WRED profile using the command wred from CONFIGURATION mode.
Early Warning
Total Buffer Space
2. The command wred places you in WRED mode. From this mode, specify minimum and maximum
threshold values using the command threshold.
574 Quality of Service
No Packets Buffered
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