Fibre Channel (SAN)

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Occasional Contributor
Posts: 7
Registered: ‎10-28-2009

How to tell if a problem is SFP or cabling?

I have an ISL that went down between two Brocade DCX-4S directors. Both ports appear that there is nothing plugged in and are in an OFFLINE state and will not go into a healthy or online state. We are running FOS 6.3.0b on both directors. I did a sfpshow at site A it shows the following:

RX Power:    -6.3    dBm (235.6 uW) 1.0    uW   794.0  uW  25.0   uW   501.0  uW

TX Power:    -4.7    dBm (341.5 uW) 38.0   uW   794.0  uW  76.0   uW   501.0  uW

I then did a sfpshow at site B and it shows the following:

RX Power:    -6.2    dBm (239.4 uW) 1.0    uW   794.0  uW  25.0   uW   501.0  uW

TX Power:    -inf    dBm (0.0   uW) 38.0   uW   794.0  uW  76.0   uW   501.0  uW

Please notice the TX power. Does this mean that the SFP at site B is the problem or could it still be a cabling problem somewhere? Thanks in advance.

Peter



Super Contributor
Posts: 644
Registered: ‎03-01-2007

Re: How to tell if a problem is SFP or cabling?

--->>> Both ports appear that there is nothing plugged in and are in an OFFLINE state and will not go into a healthy or online state.

Make sure Port's are Enable and not set as Persistent Disable.

command's "portenable" "portcfgpersistentenable"

Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: How to tell if a problem is SFP or cabling?

Hi,you can check through portshow cmnd. go through  help portshow.

connect the cable to another port , see whether the ISL is formed or not. by this you can come to know that the SFP is faulty or not.otherwise check the cable status through portstatsshow cmnd. do portstatsclear and then portstatsshow, porterrshow, if you will get media related value is increasing like enc-out, crc error.

you can also do portdisable and enable.

do a portflagsshow, you will come to know thw port is active or not.

do portloginshow port no-- to check whether the port is doing Flogi or not

Super Contributor
Posts: 260
Registered: ‎04-09-2008

Re: How to tell if a problem is SFP or cabling?

To me it seems site B is at fault but the way I used to ascertain is to look at the following

diagshow - runs tests on each port

errdump -r (a few lines, see if port turned marginal at site B)

fabriclog -s - if SFP power was low the port would have started flapping long ago.

sfpshow on both sides which you have already executed.

portshow for the port @ site B

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