02-21-2013 02:45 PM
I have Brocade DCX directors and all of the ports have the fillword set to 0. Should I go ahead and set all ports fillword to 3. As we move forward we are adding more and more 8gb devices and none of them are fillword 3. Is there a downside to settings all ports to fillword 3? Will 2gb or 4gb devices still work with the fillword set to 3?
02-22-2013 09:03 AM
Below is a little background on Fabric OS (FOS) link initialization and fill word primitive configuration for Brocade
8G Fibre Channel platforms. By providing the flexibility to choose primitives for link initialization and fill word
configuration, Brocade ensures full interoperability with all 8G capable FC HBAs and storage devices.
Up through the FOS v6.1.1 release, Brocade Fibre Channel switches used IDLE primitives both during link
initialization and for fill words (denoted as “IDLE/IDLE”). This ensured successful link initialization between
Brocade switch ports and end devices operating at 1G/2G/4G speeds.
With the introduction of 8G Fibre Channel, FC-PI-4 and FC-FS-3 standards stated that ARB should be used as
fill words for lowering emission. To comply with the published FC standards, Brocade introduced options for
ARB/ARB and IDLE/ARB link initialization/fill word support.
However, some 8G devices are not capable of properly establishing links with Brocade 8G Fibre Channel
switches when ARB/ARB or IDLE/ARB primitives are used. These 8G devices require the legacy IDLE/IDLE
sequence to achieve successful link initialization. To address this issue, Brocade has provided the ability to
configure any of the three possible combinations (IDLE/IDLE, ARB/ARB, or IDLE/ARB) for link initialization and
fill words. Any of these modes can be configured on an individual port basis using the CLI portcfgfillword. This
CLI also provides an option to automatically switch from ARB/ARB to IDLE/ARB if the former is not able to
successfully establish a link. (Please see the CLI documentation in the Appendix or in the FOS Command
Reference Manual for further details). This capability is available in FOS v6.3.1 and later versions of firmware.
In summary, FOS v6.3.1 and later versions support the following modes for 8G F_Ports as a per port
Mode 0 Use IDLE in link init and IDLE as fill word
Mode 1 Use ARB in link init and ARB as fill word
Mode 2 Use IDLE in link init and ARB as fill word
Mode3 Try mode 1 first; if it fails then try mode 2