Users Guide

148 Fabric OS Administrator’s Guide
53-1002920-02
Buffer credit recovery
5
Buffer credit recovery over an EX_Port
Buffer credit recovery is supported on a Fibre Channel router (FCR) EX_Port that connects over an
inter-fabric link (IFL) to an edge fabric E_Port when the following conditions are met:
• The FCR and the switch at the other end of the IFL must both run Fabric OS v7.1 or later.
• The FCR and the switch at either end of the IFL must both support 16 Gbps or 8 Gbps. Buffer
credit recovery is not supported if the EX_Ports do not support the same data rate.
• Either end of the IFL must support buffer credit recovery.
• If the inter-fabric link (IFL) connects devices that support 8 Gbps only, long-distance mode
must also be enabled. Long-distance mode can be enabled or disabled on devices that
support 16 Gbps.
• Virtual Channel flow control (VC_RDY) or Extended VC flow control (EXT_VC_RDY) mode must
be in use. Buffer credit recovery is not supported for EX_Ports when normal (R_RDY) flow
control mode is in use.
The feature is enabled automatically during a link reset if the conditions are met. If the capabilities
at either end of the EX_Port-to-E_Port link are not matched, the link will come up, but refer to the
Fabric OS Command Reference for lists of devices and blades that support 16 Gbps and 8 Gbps.
Enabling and disabling buffer credit recovery
To disable buffer credit recovery on a port, perform the following steps.
1. Connect to the switch and log in using an account assigned to the admin role.
2. Enter the portCfgCreditRecovery command and include the -disable option.
The following example disables buffer credit recovery on port 1/20.
switch:admin> portcfgcreditrecovery 1/20 -disable
To enable buffer credit recovery on a port for which it has been disabled, perform the following
steps.
1. Connect to the switch and log in using an account assigned to the admin role.
2. Enter the portCfgCreditRecovery command and include the -enable option.
The following example enables buffer credit recovery on port 1/20.
switch:admin> portcfgcreditrecovery 1/20 -enable