Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 45)

Default queue depth limits for FastIron X Series devices
The following table defines the default maximum queue depth values per port, per traffic class. The
Brocade device drops the packets that cause the port to exceed these limits.
NOTE
The SX-FI48GPP Interface module supports 48 tri-speed (10/100/1000) ports. When the ports are
configured at lower speeds, for example, 100 Mbps or 10 Mbps, the maximum queue depth is less than
256 when egress congestion occurs at the front-end Network Processor (NP) of the SX-FI48GPP
module. If egress congestion occurs at the back-end NP of the SX-FI48GPP module, the maximum
queue depth is 4095. The limit for buffer sharing is 4088.
Default maximum queue depth TABLE 7
Port type Maximum queue depth per
port, per priority 0 - 6 Maximum queue depth
per port, per priority 7 Total maximum queue
depth
1 Gbps port 96 224 896
10 Gbps port without jumbo
enabled 400 704 3504
10 Gbps port with jumbo
enabled 352 640 3104
Configuring the total transmit queue depth limit for FastIron X Series
devices
NOTE
To configure the total transmit queue depth limit on a third-generation module, refer to
Buffer profile
configuration on page 47.
To set the total transmit queue depth limit on a port, enter a command such as the following.
device(config)#qd 2 2049
This command sets the queue depth limit on port 2 to 2049. Packets are added to the port's outbound
queue as long as the packets do not cause the port to exceed 2048 buffers. If the port reaches its
queue depth limit of 2049, any new packets attempting to enter the port transmit queue will be dropped
until at least one buffer is freed.
Syntax: qd port limit
The limit variable can be a value from 0 through 4095. Table 7 on page 45 lists the default values.
Default queue depth limits for FastIron X Series devices
FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide 45
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