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Fabric OS Administrator’s Guide
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Buffer credit recovery
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Buffer credit recovery
Buffer credit recovery (CR) 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 recover attempt is initiated. During link reset, the frame and credit loss counters are reset
without performance degradation.
This feature is supported on E_Ports, F_Ports, and EX_Ports. VE_Ports and VEX_Ports do not
support the portCfgFportBuffers or portCfgLongDistance commands.
Buffer credit recovery is enabled automatically across any long-distance connection for which the
E_Port, F_Port, or EX_Port buffer credit recovery mechanism is supported. For 16-Gbps FC devices
and blades (Brocade 6505, 6510, 6520, CR16-4, CR16-8, FC8-32E, FC8-48E, FC16-32, FC16-48),
you can use the portCfgCreditRecovery command to disable or enable buffer credit recovery on a
port.
Buffer credit recovery over an E_Port
To support buffer credit recovery, E_Ports must be connected between devices that support 16
Gbps or between devices that support 8 Gbps.
•
Devices that support 16 Gbps:
-
Brocade 6505, 6510, 6520
-
FC8-32E, FC8-48E,FC16-32, FC16-48
•
Devices that support 8 Gbps:
-
Brocade 300, 5100, 5300, 5410, 5424, 5450, 5480, VA-40FC
-
FC8-16, FC8-32, FC8-48
If a device that supports 16 Gbps is connected to a device that supports only 8 Gbps, buffer credit
recovery is disabled, even if both devices are running 8 Gbps.
The buffer credit recovery feature for E_Ports is enabled for the following flow-control modes:
•
Normal (R_RDY)
•
Virtual Channel (VC_RDY)
•
Extended VC (EXT_VC_RDY)
Buffer credit recovery over an F_Port
Buffer credit recovery for F_Ports is supported for F_Port-to-N_Port links between a Brocade switch
and Access Gateway, between a Brocade switch and an adapter, and between an Access Gateway
and an adapter. For an F_Port on a Brocade switch connected to an Access Gateway, the following
conditions must be met:
•
Both devices must run Fabric OS v7.1 or later.
•
Fabric OS must support buffer credit recovery at either end of the link.
•
If both devices support16 Gbps, the flow-control mode can be either Normal mode (R_RDY) or
VC mode (VC_RDY); otherwise the flow-control mode must be R_RDY.
Содержание Fabric OS 7.1.0
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Страница 116: ...116 Fabric OS Administrator s Guide 53 1002745 02 Inter switch links 4 FIGURE 7 Virtual channels on a QoS enabled ISL ...
Страница 132: ...132 Fabric OS Administrator s Guide 53 1002745 02 Frame Redirection 4 ...
Страница 194: ...194 Fabric OS Administrator s Guide 53 1002745 02 Ports and applications used by switches 6 ...
Страница 254: ...254 Fabric OS Administrator s Guide 53 1002745 02 Brocade configuration form 8 ...
Страница 274: ...274 Fabric OS Administrator s Guide 53 1002745 02 Validating a firmware download 9 ...
Страница 302: ...302 Fabric OS Administrator s Guide 53 1002745 02 Creating a logical fabric using XISLs 10 ...
Страница 344: ...344 Fabric OS Administrator s Guide 53 1002745 02 Concurrent zone transactions 11 ...
Страница 374: ...374 Fabric OS Administrator s Guide 53 1002745 02 Setting up TI over FCR sample procedure 12 ...
Страница 432: ...432 Fabric OS Administrator s Guide 53 1002745 02 Access Gateway N_Port failover with FA PWWN 16 ...
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Страница 490: ...490 Fabric OS Administrator s Guide 53 1002745 02 Ports on Demand 18 ...
Страница 498: ...498 Fabric OS Administrator s Guide 53 1002745 02 Supported topologies for ICL connections 19 ...
Страница 626: ...626 Fabric OS Administrator s Guide 53 1002745 02 Preparing a switch for FIPS B ...
Страница 630: ...630 Fabric OS Administrator s Guide 53 1002745 02 Hexadecimal Conversion C ...
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