Reference Guide

For an F_Port on a Brocade switch or Access Gateway connected to an adapter, the following conditions must be met:
∙ The Brocade switch or Access Gateway must run Fabric OS v7.1 or later.
∙ Fabric OS must support buffer credit recovery at both ends of the link.
∙ The adapter must be running HBA v3.2 firmware or later.
∙ The adapter must operate at maximum speed.
∙ The flow-control mode must be R_RDY.
The feature is enabled automatically during a link reset if the conditions are met. If the conditions for buffer credit recovery are not met,
the link will come up, but buffer credit recovery will not be enabled.
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 32, 16, 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 and 32 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
32, 16, and 8 Gbps.
Enabling and disabling buffer credit recovery
NOTE
By default, buffer credit recovery is not enabled on any of the platforms.
1. To disable buffer credit recovery on a port, perform the following steps.
a) Connect to the switch and log in using an account assigned to the admin role.
b) 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
2. To enable buffer credit recovery on a port for which it has been disabled, perform the following steps.
a) Connect to the switch and log in using an account assigned to the admin role.
b) 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
Buffer-to-Buffer Credits and Credit Recovery
Brocade Fabric OS Administration Guide, 8.0.1
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