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Cisco Bug: CSCvt89457 - port in Link failure or not-connected state cycling between E_SPEED_SYNC_ACQ and E_SPEED_SIG_LOSS

Last Modified

Jun 08, 2020

Products (1)

  • Cisco MDS 9000 Series Multilayer Switches

Known Affected Releases

8.4(1a)

Description (partial)

Symptom:
Port on MDS 9710 32G module DS-X9648-1536K9 shows  (Link failure or not-connected).

Transceiver details shows RxPower going in and out of "--  low-alarm":

<pre>
MDS9700# show int fc7/31 transceiver details 

fc7/31 sfp is present 
    Name is CISCO-AVAGO     
    Manufacturer's part number is SFBR-57G5MZ-CS1 
    Revision is V03 
    Serial number is AVD2352W3ZF     
    Cisco part number is 10-3206-01
    Cisco pid is DS-SFP-FC32G-SW     
    FC Transmitter type is short wave laser w/o OFC (SN)
    FC Transmitter supports short distance link length
    Transmission medium is multimode laser with 50 um aperture (M5)
    Supported speeds are - Min speed: 8000 Mb/s, Max speed: 32000 Mb/s
    Nominal bit rate is 28000 Mb/s
    Link length supported for 50/125um OM3 fiber is 70 m
    Cisco extended id is unknown (0x0)

    No tx fault, no rx loss, no sync exists, diagnostic monitoring type is 0x68
    SFP Diagnostics Information:
----------------------------------------------------------------------------
                                     Alarms                  Warnings
                                High        Low         High          Low
----------------------------------------------------------------------------
  Temperature   26.85 C         75.00 C     -5.00 C     70.00 C        0.00 C
  Voltage        3.34 V          3.63 V      2.97 V      3.46 V        3.13 V
  Current        7.50 mA        10.00 mA     2.00 mA     8.50 mA       3.00 mA
  Tx Power      -0.51 dBm        5.00 dBm  -12.20 dBm    2.00 dBm     -8.20 dBm
  Rx Power      -6.97 dBm        5.00 dBm  -15.20 dBm    2.00 dBm    -11.20 dBm   
  Transmit Fault Count = 0
----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning
</pre>

Then...

<pre>
MDS9710# show int fc7/31 transceiver details 

fc7/31 sfp is present 
...
  Rx Power      -6.97 dBm --     5.00 dBm  -15.20 dBm    2.00 dBm    -11.20 dBm    << Low Alarm
  Transmit Fault Count = 0
----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning
</pre>

Speed negotiation is apparently failing endlessly:

<pre>
module-7# show hardware internal fcmac port 31 speed-event 


========= FCP Port#31 Internal Speed State Machine Event Log ==========
MMDDYY HHMMSS usecs          Event                      Current State
--------------------         -----                      -------------
-                            -                          SPEED_AUTO_STATE_NF1
041720 132456 819702 (0003)  E_SPEED_SYNC_ACQ_STABLE_TMR_AC AUTO_STATE_NF1    (14)
041720 132456 788954 (0003)  E_SPEED_SYNC_ACQ_RX_GE_TX  AUTO_STATE_NM1    (0)
041720 132456 756165 (0004)  E_SPEED_SYNC_ACQ           AUTO_STATE_WFS    (0)
041720 132456 722546 (0009)  E_SPEED_INIT_AUTO_START    STATE_WSD         (0)
041720 132456 628187 (0034)  E_SPEED_SIG_LOSS           AUTO_STATE_NF1    (0)
041720 132456 108683 (0003)  E_SPEED_SYNC_ACQ_STABLE_TMR_AC AUTO_STATE_NF1    (8)
041720 132456 077915 (0003)  E_SPEED_SYNC_ACQ_RX_GE_TX  AUTO_STATE_NM1    (0)
041720 132456 045210 (0004)  E_SPEED_SYNC_ACQ           AUTO_STATE_WFS    (0)
041720 132456 012383 (000B)  E_SPEED_INIT_AUTO_START    STATE_WSD         (0)
041720 132455 902579 (0006)  E_SPEED_SIG_LOSS           AUTO_STATE_NF2    (0)
041720 132455 840573 (0003)  E_SPEED_SYNC_LOSS          AUTO_STATE_NF2    (1)
041720 132455 807624 (0048)  E_SPEED_SYNC_LOSS          AUTO_STATE_NF1    (0)
041720 132455 089674 (0003)  E_SPEED_SYNC_ACQ_STABLE_TMR_AC AUTO_STATE_NF1    (21)
041720 132455 058893 (0003)  E_SPEED_SYNC_ACQ_RX_GE_TX  AUTO_STATE_NM1    (0)
041720 132455 026198 (0004)  E_SPEED_SYNC_ACQ           AUTO_STATE_WFS    (0)
041720 132454 992610 (000B)  E_SPEED_INIT_AUTO_START    STATE_WSD         (0)
</pre>

No notifications that this is happening are seen. Port should probably be brought down error disabled with a message about speed negotiation failing.

Conditions:
Unknown hardware condition on the fc7/31 link causing repeated Sync acquired and then signal loss.
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