Configuration Guide User guide

FastIron Configuration Guide 599
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Dynamic buffer allocation for FCX, FWS, and ICX devices
Configuring buffer sharing on FCX and ICX devices
Network congestion can be caused by various reasons such as port shaping, flow control received
on the link due to congestion on the peer, or oversubscription of the egress line rate.
To support priority queuing, FCX and ICX devices support a configurable amount of guaranteed
buffers and descriptors per (port, queue) pair. For information about guaranteed buffers and
descriptors, refer to “Configuring buffer profiles” on page 590.
In addition, FCX and ICX devices support configurable shared buffer pools, which help absorb
traffic bursts without packet loss. For a given (port, queue) pair, if its buffer usage exceeds the
guaranteed limit, it will start using buffers in the sharing pool. The shared buffers are apportioned
among the 1 Gbps, 10 Gbps, 16 Gbps, and stacking ports.
Buffer sharing is always enabled. You can configure buffer sharing by changing the buffer sharing
level. To configure the buffer sharing level, enter a command similar to the following.
Brocade(config)# qd-share-level 2
Syntax: qd-share-level <level>
The <level> variable is the buffer sharing level, which is a decimal value. The range of valid values
for FCX is from 1 to 8. The range of valid values for an ICX 6610 is from 2 through 8.
For descriptions of the buffer sharing levels for FCX devices, refer to “FCX buffer sharing levels” on
page 600.
For descriptions of the buffer sharing levels for ICX 6610 devices, refer to “ICX 6610 buffer sharing
levels” on page 600.
For descriptions of the buffer sharing levels for ICX 6430 and 6450 devices, refer to “ICX 6430 and
ICX 6450 buffer sharing levels” on page 601.
Per Queue details The names of the queues
Buffers The total number of buffers allocated to the queue
Descriptors The total number of descriptors allocated to the queue
TABLE 110 Field definitions for the output of show qd-buffer-profile command
Field Description