Fibre Channel (SAN)

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Occasional Contributor
Posts: 7
Registered: ‎09-22-2009

How to read correctly SFPshow?

HI ,

I have here several Brocade 300 riunning on FOS 6.4.2

I see in SFPShow the following :

=============
Port 19:
=============
Identifier:  3    SFP
Connector:   7    LC
Transceiver: 5401001200000000 200,400,800_MB/s SM lw Long_dist
Encoding:    1    8B10B
Baud Rate:   85   (units 100 megabaud)
Length 9u:   10   (units km)
Length 9u:   100  (units 100 meters)
Length 50u:  0    (units 10 meters)
Length 62.5u:0    (units 10 meters)
Length Cu:   0    (units 1 meter)
Vendor Name: BROCADE        
Vendor OUI:  00:05:1e
Vendor PN:   57-1000027-01  
Vendor Rev:  A  
Wavelength:  1310 (units nm)
Options:     003a Loss_of_Sig,Tx_Fault,Tx_Disable
BR Max:      0  
BR Min:      0  
Serial No:   UDN11104B101323
Date Code:   110204 
DD Type:     0x68
Enh Options: 0xb0
Status/Ctrl: 0xb2
Alarm flags = 0x5, 0x40
Warn Flags = 0x5, 0x40
                                          Alarm                  Warn
                                      low        high       low         high
Temperature: 42      Centigrade     -15         100        -10         95
Current:     29.442  mAmps          5.000       80.000     10.000      70.000
Voltage:     3283.9  mVolts         2970.0      3600.0     3100.0      3470.0
RX Power:    -1.8    dBm (662.8 uW) 25.1   uW   1412.5 uW  39.8   uW   891.2  uW
TX Power:    -3.6    dBm (434.6 uW) 89.1   uW   1412.5 uW  141.3  uW   891.3  uW

Do I read it right that the SFP believes he is connected to a 9 Micorn Cable with the Distance of 10 Km ?

Thanks

Regular Contributor
Posts: 201
Registered: ‎11-24-2009

Re: How to read correctly SFPshow?

Hi britta_luebbert,

SFP+ doesn't believe in anything. The static part of sfpShow output is based on Serial ID data stored in SFP's internal EEPROM, in this case bytes 14 and 15 of Base ID data. This is hardcoded into SFP and merely shows its defined characteristics.

For more details please refer to the Small Form-factor Pluggable Transciever Multi-Source Agreement (SFP MSA).

Hope this helps,

Linar

Occasional Contributor
Posts: 7
Registered: ‎09-22-2009

Re: How to read correctly SFPshow?

thanks for this , so I probably need to rephrase my Question , I need ot find out how long the Calbe is between 2 Sites, I don't have trunking on the Switches , just 3 ISL's .

So is there a Way for me to find out what the Distance is with the Supportshow or a command on the Siwtches witohut having extra licenses ?

Regular Contributor
Posts: 201
Registered: ‎11-24-2009

Re: How to read correctly SFPshow?

Short answer is switches don't know that.

Long answer is, if you set E-Port to dynamic long distance (LD) mode switches will estimate the distance based on round-trip time. It's more or less accurate when measured over a dark fiber link, but if there is any active equipment such as xWDM transponder these measurements are unstable and more often than not mean nothing.

LD mode requires Extended Fabrics license though, so if there ain't one you can't do it.

The best way is to review OTDR certification sheets for long distance cable segments. These are normally prepared by cable guys as part of the acceptance test.

Hope this helps,

Linar

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