Fabric OS v6.4.1 Release Notes v1.0 Page 32 of 62
• A switch running FOS v6.4 in InteropMode 0 (Brocade Native Mode) cannot connect to an EX_Port
on an AP7420. A switch running FOS v6.4 in InteropMode 2 or InteropMode 3 can be connected
to EX ports on an AP7420.
Extended Fabrics and R_RDY Flow Control
Beginning with Fabric OS v5.1, Brocade supported the Extended Fabrics feature in conjunction with
R_RDY flow control (R_RDY flow control mode can be enabled via portCfgISLMode command). R_RDY
flow control mode that uses IDLE primitives does not support Brocade frame-based Trunking for
devices such as Time Division Multiplexor (TDM.) In order to overcome this limitation and provide
support for frame-based Trunking with Extended Fabrics, Fabric OS v6.2.0 and later has been
enhanced to support interoperability with these distance extension devices.
Fabric OS v6.3.1 allows Extended Fabrics E_Ports to operate in VC_RDY mode using either ARB or
IDLE primitives as fill words. This allows frame-based Trunking to be supported on Extended Fabrics E-
ports even when IDLE primitives are configured for these ports when operating in native VC_RDY
mode. Prior to this change, frame-based Trunking was supported only when ARB primitives were used
in VC_RDY mode. With Fabric OS v6.2 or later, frame-based Trunking is supported on Extended
Fabrics E_Ports regardless of whether IDLE or ARB primitives are used when operating in native
The portcfglongdistance CLI parameter “VC Translation Link Init” is now overloaded to specify if the
long distance link should use IDLE or ARB primitives. By default, vc_init is enabled. If vc_init is
enabled, the long distance link will use ARB primitives. If vc_init is disabled, the link will use IDLE
Buffer to Buffer Credit Recovery feature is not supported on Extended Fabrics E_Port when it is
configured to use IDLE primitives. The user must disable buffer to buffer credit recovery feature using
the command portcfgcreditrecovery and specifying the disable option; otherwise, the link will
The Adaptive Networking SID/DID Traffic Prioritization QoS feature is not supported on Extended
Fabrics E_Ports when IDLE primitives are configured on these ports. This is because in this mode only
data Virtual Channels are available while QoS related virtual channels are not available.
When connecting to an extension device that does not support ARB primitives (such as some TDM
products), the following configuration must be used:
portcfgqos -disable <port>
portcfgcreditrecovery –disable <port>
portCfgLongDistance <port> <LD|LD> 0 <distance>
The fabric parameter “fabric.ops.mode.longdistance” is now deprecated and should not be used.
• When ports on a 5470 embedded switch are configured for 8G, Emulex HBAs may not
login in time and cause boot over SAN failures. Setting the port to auto-negotiate allows
these HBAs to log in correctly at 8G.
• POST diagnostics for the Brocade 5100 have been modified beginning with FOS v6.3.1b
and v6.4.0 to eliminate an “INIT NOT DONE” error at the end of an ASIC diagnostic port
loopback test. This modification addresses BL-1020 Initialization errors encountered
during the POST portloopbacktest. (Defect 263200)
• It is recommended that no more the 50 F_Port Top Talkers be enabled on a 48000
director in a large fabric (>4000 devices).