Demistifying ISL configuration on Brocade FOS

Hi all,

I'm trying to understand how to build a good configuration for ISL link on Brocade environment, based on Brocade RN.

Here what I have tried and I need confirmation on several points for my knownledge of Brocade.

Please correct me on points that are not good.

Brocade has two modes for flow control on ISL : R_RDY or VC_RDY

R_RDY is based on FC standard (and is also called Exchange Linbk Protocol mode 2 : ELP 2).

In these mode, the primitives used in the frames for Linkinit is Idle and for fillword is Idle.

as it is an FC standard, this mode is used for ISL with interop mode with others switches (Mcdata, Cisco).

It is also needed in certain circonstances for Long distance with TDM or SONET interconnection equipment that only support Idle primitives.

in order to put a port on R_RDY, the command is portcfgislmode X, 1

VC_RDY (VC=virtual circuit) is the Brocade proprietary flow control (and is ELP mode 1 ?).

This mode only works between FOS switchs.

this mode is needed if you want to use some Brocade , like trunking for ISL.

by default, this mode use ARB frames primitives (used by Brocade Virtual Channels) as linkinit and ARB as fillword.

in order to put a port on VC_RDY, the command is portcfgislmode X, 0

since FOS 5.1, R_RDY is supported for long distances, but trunking is impossible in R_RDY.

Since FOS Depuis 6.1.2, VC_RDY mode can use Idle primitives as fillword (only ARB primitives as fillword before).

this was added in order to allow to do brocade trunking on interconnection equipment that doesn't support ARB primitives.

so in the command portcfglongdistance, there was an new option :

if vc_translation_link_init is 0 --> IDLE primitives as fill word (VC_Init = VC Link Init = OFF) --> arb/idle

if vc_translation_link_init is 1 --> ARB primitives as fill word (VC_Init = VC Link Init = ON) --> arb/arb = default mode for brocade isl

A point is not clear on Brocade documents :

the buffer-to-buffer credit recovery feature and QOS are not supported on ISL with Idle primitives.

so you need to disable it with portcfgcreditrecovery --disable command and portcfgqos --disable command

in R_RDY it is clear that we are in idle/idle mode, but in vc_rdy, we are in arb/arb or arb/idle

do we need in vc_rdy arb/idle to disable both qos and credit recovery feature ?

Another point is this one :

until FOS 6.1.1 (before 8G arrives), all F-ports were in linkinit=IDLE / Fillword=IDLE.

but with 8G, ARB primitives are privileged because it use less energy.

so on FOS 6.1.2, Brocade added the command portcfgFillword in order to configure F-port mode.

two modes where possible on 6.1.2 :

0= linkinit=IDLE / Fillword=IDLE

1= linkinit=ARB / Fillword=ARB

On FOS 6.3.1, Brocade added modes 2 and 3 to portcfgFillword in order to manage fillword for ports :

0= linkinit=IDLE / Fillword=IDLE

1= linkinit=ARB / Fillword=ARB

2= linkinit=IDLE / Fillword=ARB

3= try mode 1, if it fails, mode 2

But now, there is a problem, this command is also usable on E-Port !

So, could you confirm this in VC_RDY mode :

if vc_translation_link_init is 0 --> IDLE primitives as fill word (VC_Init = VC Link Init = OFF), it requires portcfgfillword to be set to 0 (incompatible other values)

if vc_translation_link_init is 1 --> ARB primitives as fill word (VC_Init = VC Link Init = ON), it requires portcfgfillword to be set to 1,2 ou 3

a warning message appears in the case you try to configure bad fillword according to vc_init).

In R_RDY mode, vc_translation_link_init and Trunk port (portcfgtrunkport) value are ignored.

But we can configure a 8Gb ISL in R_RDY and with portcfgfillword in mode 3 ??!!

No warning message appears.

it seems obvious to me...

Last but not least, If i am in VC_RDY arb/arb (default mode) and i configure long distance in cli between two same FOS with :

portcfglongdistance 1 LS 0 100

in webtools, i have this pop up :

"dls should be disabled while enabling long distance link with credit recovery"

how can we understand a such message ? am I in the wrong aptpolicy (i am in aptpolicy 3 0 which is the default).

I have a DS5300 with an isl to a DS5100 model --> is a problem with asics that are different (goldeneye2 /condor2)

please help me understand a such complicated way to manage ISL...