Factory defaults vs user defined on Vitrual Connect Fibre Channel

[chuckk281]

Lisa had a customer SAN issue:

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Have a government customer who has the 8 port VC FC module.   When configured with USER defined WWN ranges, they cannot see the Hitachi storage  (via a Brocade switch) on the back end.  Immediately setting the configuration to factory default, they can see the LUNs.   Has anyone ever seen this?

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Terri replied:

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Lisa,

Assuming this is the 8GB VCFC 20-port module, system option # 346 needs to be set on the Hitachi. This is a Hitachi setting. It allows the Hitachi to work with Virtual Connect virtual addressing

There is also a known issue with connectivity issues when attaching 8 GB Brocade to 8 GB Brocade depending on the Brocade model. What Brocade FOS is running on the Brocade switch?

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More to come in this story. Have you had these sorts of troubles. If so, tell us how you solved them.

[chuckk281]

Cristoph had some info:

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Hi

Portcfgfillword need to be at 3 for 8 GB ports.

I still try to find a definite answer if the setting  Mode 3 is only active if port are running on 8 GB. The Brocade papers are not very clear.  If you go with mode 3 you have a failback to idle if arbff is not working. 

Modes

0—Idle for link init, idle for fill word

1—Arb(ff) for link init, arb(ff) for fill word (not supported with EVA or XP storage arrays)

2—Idle for link init, arb(ff) for fill word

3—Initially attempts mode 1 link initialization. If unsuccessful in achieving active state, reverts to mode 2. Steady state fill word is arb(ff) (not supported with XP storage arrays earlier than Fabric OS 6.4.0a.)

8Gb link initialization and fill words

Overview

The Fibre Channel Physical Interfaces (FC-PI) standard defines the requirements for a physical layer. It considers all aspects of transmit, receive, and cable-plant performance requirements for optical and electrical links. The FC-PI standard has been modified to support new physical-layer variants that operate at higher data rates than those specified in FC-PI-2. The standard enables interoperability of transmitter devices, receiver devices, interconnects, and components from different manufacturers.

New variants include support for a data rate of 800 MB/s. The previous implementation by Brocade was to use Idles for link initialization and as fill words, which works for 1Gb, 2Gb, 4Gb, and most 8Gb devices. However, some of the new 8Gb devices may require that the ARB(FF)/ARB(FF) sequence have successful link initialization. Brocade has developed an implementation of ARB(FF)/ARB(FF) for initialization and fill words. The portcfgfillword command, first introduced in Fabric OS 6.1.2, configures the ARB(FF)/ARB(FF) implementation. See the Fabric OS Command Reference Manual supporting Fabric OS v6.4 for details on the portcfgfillword command

By default, Brocade switches running at 8-Gbps speed send “IDLE” as the fill word. This is non-standard behavior (see standard below) and causes our receiver to train poorly resulting in decode errors.

Applicable Fibre Channel Switch Standard:

www.t11.org

    It is established in FC-PI-4 sec 5.8 that a port operating at 8GFC shall use   scrambling/ELP.

    FC-PI-4 Rev 8.0 states:

    5.8 Frame scrambling and emission lowering protocol

    8GFC shall use the frame scrambling as stated in FC-FS-2 AM1 

    (reference [5]) and emission lowering protocol as stated in FC-FS-2 

    (reference [4]). 1GFC, 2GFC, and 4GFC do not use scrambling.

    FC-FS-3  Rev 0.70 states:

    5.2.4.9 ARBff

    ARBff is a Primitive Signal used to maintain link synchronization on 

    links using Emission Lowering Protocol. ARBff shall be treated the 

    same as Idle.  ARBff shall be transmitted on links using Emission 

    Lowering Protocol during periods of time when frames, other Primitive 

    Signals, or Primitive Sequences are not required to be transmitted.

    See 8.3 for the requirements for the insertion of Fill Words between frames.

8G FC implementation is required to use the ELP, and if ELP is used it is required to transmit ARBff.

To ensure interoperability between Brocade and QLogic switches, use the “portCfgFillWord” command to set the fill word of the connecting port to option 3 (ARBFF/ARBFF). 

    Brocade5100:admin> portcfgfillword 0

    Usage: portCfgFillWord PortNumber  Mode

    Mode: 0/-idle-idle   - IDLE in Link Init, IDLE as fill word (default)

         1/-arbff-arbff - ARBFF in Link Init, ARBFF as fill word

         2/-idle-arbff  - IDLE  in Link Init, ARBFF as fill word (SW)

         3/-aa-then-ia  - If ARBFF/ARBFF failed, then do IDLE/ARBFF

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Hope this helps.