Configuration Guide User guide

588 FastIron Configuration Guide
53-1002494-02
Dynamic buffer allocation for QoS priorities for FastIron X Series devices
Configuring a buffer profile and defining the queue depth limits
1. Create a buffer profile and assign it to a port. For example, to create buffer profile 2 and assign
it to port 1/1, enter the following command.
Brocade(config)#qd 1/1 profile-id 2
Syntax: [no] qd <slotnum>/<portnum> profile-id <number>
The <number> variable specifies the buffer profile ID associated with the
<slotnum>/<portnum>. The buffer profile ID can be a number from 1 through 7. Profile 0 is
reserved for buffer sharing.
2. Configure the total transmit queue depth limit associated with the buffer profile. For example,
to change the total transmit queue depth limit for buffer profile 2 to 1000, enter the following
command.
Brocade(config)#qd 1/1 1000
Because port 1/1 is associated with buffer profile 2, this command sets the queue depth limit
for buffer profile 2 to 1000. Packets are added to the outbound queue of a port as long as the
packets do not cause the port to exceed 1000 buffers. If the port reaches its queue depth limit
of 1000, any new packets attempting to enter the transmit queue will be dropped until at least
one buffer is freed.
Syntax: [no] qd <slotnum>/<portnum> <limit>
The <limit> variable can be a value from 0 through 4095. The default is 4095.
3. If desired, configure the queue depth limit for a given traffic class. For example, to change the
queue depth limit for buffer profile 2 to 300 for packets with a traffic class of 1, enter the
following command.
Brocade(config)#qd 1/1 300 1
For ports that use buffer profile 2, packets with priority 1 are added to the outbound queue as
long as the packets do not exceed 299 buffers. When the port reaches its queue depth limit of
300, packets with the given traffic class will be dropped.
Syntax: [no] qd <slotnum>/<portnum> <limit> <traffic-class>
The <limit> variable can be a value from 0 through 4095 and cannot exceed the total transmit
queue depth limit configured in the previous step.
The sum of the queue depth limits for individual traffic classes on a port does not need to
equal the total queue depth limit for the port:
• If the sum of the individual traffic class queue depth limits exceeds the total port limit and
the total port limit is reached, any buffer that gets released can be used by any traffic class
queue that has not reached its individual limit.
• If the sum of the individual traffic class queue depth limits is less than the total port limit,
the remaining buffers can be used only by packets with a priority of 7.
The <traffic-class> variable can be a value from 0 through 7, where 7 is the highest priority
queue.
4. Enter the write memory command to save the configuration.