Brocade BigIron RX Series Configuration Guide - Manual (Page 576)

498 BigIron RX Series Configuration Guide
53-1002484-04
Configuring packet drop priority using WRED
18
Syntax: [no] qos queue-type <queue-number> wred drop-precedence <policing-status>
drop-probability-max
<p-max%>
The <queue-number> variable is the number of the forwarding queue that you want to configure
drop-precedence for. There are four forwarding queues on device. They are numbered 0 to 3 with
zero as the lowest priority queue and three the highest.
The <policing-status> variable indicates the traffic policing status for which you want to configure
drop-precedence.
The <p-max%> variable defines the maximum drop probability in when the queue size is at the
value configured for max-avg-q-size. This value is expressed as a percentage.
Configuring the maximum instantaneous queue size
You can set the maximum size to which a queue is allowed to grow. Packets that cause the queue
to grow beyond this setting are unconditionally dropped. To set the maximum instantaneous queue
size for queues with a queue type of 1 to 32000, use the following command.
BigIron RX(config)#qos queue-type 1 max-queue-size 32
Syntax: [no] qos queue-type <queue-number> max-queue-size <max-queue>
The <queue-type> variable is the number of the forwarding queue type that you want to configure
the instantaneous-queue-size parameter for. There are eight forwarding queue types on device
Routers. They are numbered 0 to 3.
The <max-queue> variable is the maximum size to which a queue is allowed to grow. It is defined in
Kbytes. The default values are shown in
Table 104 .
Setting the minimum and maximum average queue size
To set the maximum average queue size for queue type 1 and drop precedence 0 to the maximum
size of 32768 Kbytes, use the following command.
BigIron RX(config)#qos queue-type 1 wred drop-precedence 0 max-avg-queue-size
32768
Syntax: [no] qos queue-type <queue-type> wred drop-precedence <drop-precedence-value>
max-avg-queue-size <max-size>
To set the minimum average queue size to the maximum size of 16 Kbytes, use the following
command.
BigIron RX(config)#qos queue-type 1 wred drop-precedence 0 min-avg-queue-size 64
Syntax: [no] qos queue-type <queue-type> wred drop-precedence <drop-precedence-value>
min-avg-queue-size <min-size>
The <queue-type> variable is the number of the forwarding queue type that you want to configure
drop-precedence for. There are eight forwarding queue types on BigIron RX Routers. They are
numbered 0 to 3.
The <drop-precedence-value> variable for the drop-precedence parameter is the TOS/DSCP value
in the IPv4 or IPv6 packet header. It determines drop precedence on a scale from 0 - 3. Packets
than contain a DSCP value of 0 are least likely to be dropped and packets with a value of 3 are
most likely to be dropped. The default value is 0.