Users Guide

146 Fabric OS Administrator’s Guide
53-1002920-02
Buffer credit recovery
5
When a port is configured with the –buffers option
A firmware downgrade is blocked when a port is configured as a long-distance port by means of the
–buffers option. The following warning message is displayed:
Downgrade to selected version is not allowed because few ports are configured with
Longdistance -buffers option. Please remove the configuration using
portcfglongdistance <slot>/<port> L0 CLI or change the configuration with
-distance option on the console.
Configuring credits for a single VC
You can alter the default credit allocation for a normal distance E_Port or EX_Port so that a specific
number of credits is allocated to a port. When you allocate a specific number of credits to an
E_Port or EX_Port, the number of credits specified override the default credit allocation. When this
feature is disabled, the default credit model is restored. Only a normal distance E_Port and EX_Port
can utilize the new credit model, and the allocated credits are reserved only for that port.
When this feature is enabled, the E_Port credit configuration is persistent across system reboots
and High Availability (HA) failover.
This feature is supported on E_Ports and EX_Ports. It does not support ports configured as F_Ports,
Mirror Ports, L_Ports, and Longdistance Ports. If E_Port credits are configured on ports, you cannot
move the ports from one logical switch to another. This feature is not applicable on ICL_ports.
Increasing credits for normal distance E_Ports
Use the following steps to allocate credits to an E_Port.
1. Connect to the switch and log in using an account assigned to the admin role.
2. Enter the portCfgEPortCredits --enable
command to allocate credits to an E_Port. In the
following example, 14 credits are allocated to an E_Port.
switch:admin> portcfgeportcredits --enable 12/6 14
Success
3. Enter the portCfgEPortCredits --show command to verify that the credits have been allocated
to the E_Port. In the following example, it is verified that 14 credits have been allocated to the
E_Port.
switch:admin> portcfgeportcredits --show 12/6
E-Port Credit Configured : 14
Success.
Buffer credit recovery
Buffer credit recovery allows links to recover after buffer credits are lost when the buffer credit
recovery logic is enabled. The buffer credit recovery feature also maintains performance. If a credit
is lost, a recovery attempt is initiated. During link reset, the frame and credit loss counters are
reset without performance degradation.
Credit recovery is supported on E_Ports, F_Ports, and EX_Ports.