Configuration Guide User guide

FastIron Configuration Guide 53
53-1002494-02
Basic port parameter configuration
Syntax: show symmetric-flow-control
PHY FIFO Rx and Tx depth configuration
PHY devices on FWS devices contain transmit and receive synchronizing FIFOs to adjust for
frequency differences between clocks. The phy-fifo-depth command allows you to configure the
depth of the transmit and receive FIFOs. There are 4 settings (0-3) with 0 as the default. A higher
setting indicates a deeper FIFO.
The default setting works for most connections. However, if the clock differences are greater than
the default will handle, CRCs and errors will begin to appear on the ports. Raising the FIFO depth
setting will adjust for clock differences.
Brocade recommends that you disable the port before applying this command, and re-enable the
port. Applying the command while traffic is flowing through the port can cause CRC and other
errors for any packets that are actually passing through the PHY while the command is being
applied.
Syntax: [no] phy-fifo-depth <setting>
• <setting> is a value between 0 and 3. (0 is the default.)
This command can be issued for a single port from the IF config mode or for multiple ports from the
MIF config mode.
NOTE
Higher settings give better tolerance for clock differences with the partner phy, but may marginally
increase latency as well.
Interpacket Gap (IPG) on a FastIron X Series switch
IPG is the time delay, in bit time, between frames transmitted by the device. You configure IPG at
the interface level. The command you use depends on the interface type on which IPG is being
configured.
The default interpacket gap is 96 bits-time, which is 9.6 microseconds for 10 Mbps Ethernet, 960
nanoseconds for 100 Mbps Ethernet, 96 nanoseconds for 1 Gbps Ethernet, and 9.6 nanoseconds
for 10 Gbps Ethernet.
Brocade(config)# show symmetric
Symmetric Flow Control Information:
-----------------------------------
Symmetric Flow Control is enabled on units: 2 3
Buffer parameters:
1G Ports:
Total Buffers : 272
XOFF Limit : 240(91%)
XON Limit : 200(75%)
10G Ports:
Total Buffers : 416
XOFF Limit : 376(91%)
XON Limit : 312(75%)