Configuring Receive Data Field Size; Understanding Bit Error Thresholds - Cisco AP775A - Nexus Converged Network Switch 5010 Configuration Manual

Configuring Fibre Channel Interfaces

Configuring Receive Data Field Size

You can configure the receive data field size for native Fibre Channel interfaces (but not for virtual Fibre
Channel interfaces). If the default data field size is 2112 bytes, the frame length will be 2148 bytes.
To configure the receive data field size, perform this task:
Procedure
Step 1
Step 2
Step 3

Understanding Bit Error Thresholds

The bit error rate threshold is used by the switch to detect an increased error rate before performance degradation
seriously affects traffic.
The bit errors can occur for the following reasons:
• Faulty or bad cable.
• Faulty or bad GBIC or SFP.
• GBIC or SFP is specified to operate at 1 Gbps but is used at 2 Gbps.
• GBIC or SFP is specified to operate at 2 Gbps but is used at 4 Gbps.
• Short haul cable is used for long haul or long haul cable is used for short haul.
• Momentary synchronization loss.
• Loose cable connection at one or both ends.
• Improper GBIC or SFP connection at one or both ends.
A bit error rate threshold is detected when 15 error bursts occur in a 5-minute period. By default, the switch
disables the interface when the threshold is reached.
You can enter the shutdown/no shutdown command sequence to reenable the interface.
You can configure the switch to not disable an interface when the threshold is crossed.
The switch generates a syslog message when bit error threshold events are detected, even if the interface
Note
is configured not to be disabled by bit-error threshold events.
To disable the bit error threshold for an interface, perform this task:
OL-16597-01
Command or Action
switch# configuration terminal
switch(config)# interface fc slot/port
switch(config-if)# switchport
fcrxbufsize 2000
Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
Configuring Receive Data Field Size
Purpose
Enters configuration mode.
Selects a Fibre Channel interface and enters interface
configuration mode.
Reduces the data field size for the selected interface
to 2000 bytes. The default is 2112 bytes and the range
is from 256 to 2112 bytes.
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