GE T1000, Technical Manual

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Chapter 7
– Configuration
GE Reason Switches
REASON SWITCHES-TM-EN-3 211
11.13 WRED
WRED (Weighted Random Early Detection Configuration) menu allows configuring
storm prevention based on early detection algorithm function. This function applies
only when Weighted QoS is performed, and this field allows configuring threshold for
queues at weighted priority. Storm prevention is a way to implement quality-of-
service for a given LAN. Possible configurations are as follows.
o
Queue: shows the queues to be configured at this row;
o
Enabled : enable WRED function at the queue. Checkbox selected
means function enabled, and checkbox empty means disabled;
o
Min. Threshold: indicates minimum average traffic to switch start
dropping packets of queues 0 to 5 based on the weight configured
in the QoS Egress Port Scheduler and Shapers menu. Values
beyond this means no probability to drop packets. Values are in
percentage, and allowed values are from 0 to 100. 0 means no
traffic and 100 means all capacity traffic at a given port;
o
Max. DP1 : indicates drop probability of DPL 1 frames when traffic
at the queue is 100 %. This field allows setting a probability for
loosing packets marked with Drop Precedence Level (DPL) 1. Values
are in percentage, and allowed values are from 0 to 100. 0 means
no traffic and 100 means all capacity traffic at a given queue;
o
Max. DP2 : indicates drop probability of DPL 2 frames when traffic
at the queue is 100 %. This field allows setting a probability for
loosing packets marked with Drop Precedence Level (DPL) 2. Values
are in percentage, and allowed values are from 0 to 100. 0 means
no traffic and 100 means all capacity traffic at a given queue;
o
Max. DP3 : indicates drop probability of DPL 3 frames when traffic
at the queue is 100 %. This field allows setting a probability for
loosing packets marked with Drop Precedence Level (DPL) 3. Values
are in percentage, and allowed values are from 0 to 100. 0 means
no traffic and 100 means all capacity traffic at a given queue.
Figure below shows Drop Probability versus Average Filling Level of the DPL levels
curves.