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Nexus 5548UP 10GBase-LR switch-port Link not connected issue



I'm currently having an issue with establishing a dark fiber circuit between datacenters.  The circuit provider has tested the circuit to be good.  So, I started my testing on the local end to ensure the hardware (Switch, Switchport, Transceiver) is functioning properly at a basic level before connecting the circuit but ran into an issue.  I'm unable to establish an "UP" status on the interface I've installed the 10GBase-LR SFP with a hard loop on the transceiver within my switch.  I've tried several ports to verify it's not a switchport issue but same results.  I've replaced the 10GBase-LR (Single-Mode) with a 10GBase-SR (Multi-Mode) and the interface works perfectly.  The status changes to "UP". 


I've added some additional information below.  I'm starting think it may be a bad SFP. 


Cisco Nexus5548 Chassis
System version: 6.0(2)N2(3)


show interface ethernet 2/6
Ethernet2/6 is down (Link not connected)
 Dedicated Interface
  Hardware: 1000/10000 Ethernet, address: 002a.6a89.30c5 (bia 002a.6a89.30c5)
  MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec
  reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA
  Port mode is access
  auto-duplex, 10 Gb/s, media type is 10G
  Beacon is turned off
  Input flow-control is off, output flow-control is off
  Rate mode is dedicated
  Switchport monitor is off
  EtherType is 0x8100
  Last link flapped never
  Last clearing of "show interface" counters 00:33:05
  0 interface resets
  30 seconds input rate 0 bits/sec, 0 packets/sec
  30 seconds output rate 0 bits/sec, 0 packets/sec
  Load-Interval #2: 5 minute (300 seconds)
    input rate 0 bps, 0 pps; output rate 0 bps, 0 pps
    0 unicast packets  0 multicast packets  0 broadcast packets
    0 input packets  0 bytes
    0 jumbo packets  0 storm suppression bytes
    0 runts  0 giants  0 CRC  0 no buffer
    0 input error  0 short frame  0 overrun   0 underrun  0 ignored
    0 watchdog  0 bad etype drop  0 bad proto drop  0 if down drop
    0 input with dribble  0 input discard
    0 Rx pause
    0 unicast packets  0 multicast packets  0 broadcast packets
    0 output packets  0 bytes
    0 jumbo packets
    0 output error  0 collision  0 deferred  0 late collision
    0 lost carrier  0 no carrier  0 babble 0 output discard
    0 Tx pause

show interface ethernet 2/6 transceiver details
    transceiver is present
    type is 10Gbase-LR
    name is CISCO-SUMITOMO
    part number is SPP5200LR-C6
    revision is B
    serial number is 
    nominal bitrate is 10300 MBit/sec
    Link length supported for 9/125um fiber is 10 km
    cisco id is --
    cisco extended id number is 4
           SFP Detail Diagnostics Information (internal calibration)
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  Temperature    0.00 C        75.00 C     -5.00 C     70.00 C        0.00 C
  Voltage        0.00 V         3.63 V      2.97 V      3.46 V        3.13 V
  Current        0.00 mA       90.00 mA    20.00 mA    84.00 mA      24.00 mA
  Tx Power        N/A           3.49 dBm  -12.21 dBm    0.49 dBm     -8.21 dBm
  Rx Power        N/A     --    3.49 dBm  -18.53 dBm    0.49 dBm    -14.43 dBm
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

show interface ethernet 2/6 brief
Ethernet      VLAN    Type Mode   Status  Reason                   Speed     Port
Interface                                                                    Ch #
Eth2/6        321     eth  access down    Link not connected          10G(D) --

Re: Nexus 5548UP 10GBase-LR switch-port Link not connected issue

HI, i think your problem is about "Link length supported for 9/125um"
you must check your fiber optic , please give details about your fiber optic, but for your information: for SR SFP you need fiber 850nm and 1300 and for LR SFP you need 1310nm to 1400nm fiber, if your fiber work peroperly with SR SFP i think your fiber optic is multimode. read your fiber optic info and if it was 850nm or 1300 nm , your fiber optic is multimode .
VIP Collaborator

Re: Nexus 5548UP 10GBase-LR switch-port Link not connected issue

You may have a bad SFP. The output of the "show interface ethernet 2/6 transceiver details" shows "N/A" for its TX Power. Even if it wasn't connected to anything there should be some sort of transmit output level. 

Hope this helps.



Re: Nexus 5548UP 10GBase-LR switch-port Link not connected issue

@chrihusseyYou are correct.  After replacing the SFP, I was then able to hard loop the transceiver and see readings for TX Power.  


Thank for your help...

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