Huawei – Physical decoding errors

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When you have a strange network problem on a fiber uplink you may experience this output in display interface command:

<CAMPUS-glitchlist_lab>dis int gi0/0/12
GigabitEthernet0/0/12 current state : UP
Line protocol current state : UP
Description:to SPINE1
Switch Port, Link-type : trunk(configured),
PVID :    1, TPID : 8100(Hex), The Maximum Frame Length is 9216
IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 7cc3-8560-2e22
Last physical up time   : 2019-03-24 21:34:42
Last physical down time : 2019-03-24 21:34:13
Current system time: 2019-03-27 23:05:07
Port Mode: COMMON FIBER, Transceiver: 1000_BASE_SX_SFP
Speed : 1000,   Loopback: NONE
Duplex: FULL,   Negotiation: DISABLE
Mdi   : -,      Flow-control: DISABLE
Last 300 seconds input rate 358736 bits/sec, 313 packets/sec
Last 300 seconds output rate 6193032 bits/sec, 616 packets/sec
Input peak rate 36127856 bits/sec, Record time: 2019-03-17 01:01:27
Output peak rate 73339616 bits/sec, Record time: 2019-03-27 14:47:37

Input:  124841580 packets, 40279782184 bytes
  Unicast:                  124051275,  Multicast:                      121188
  Broadcast:                   139931,  Jumbo:                               0
  Discard:                          0,  Pause:                               0
  Frames:                           0

  Total Error:                 529186     
  CRC:                              0,  Giants:                              0
  Runts:                            0,  DropEvents:                          0
  Alignments:                       0,  Symbols:                        529186
  Ignoreds:                         0

Output:  173537172 packets, 195364958288 bytes
  Unicast:                  172372334,  Multicast:                      871683
  Broadcast:                   293155,  Jumbo:                               0
  Discard:                          0,  Pause:                               0

  Total Error:                      0
  Collisions:                       0,  Late Collisions:                     0
  Deferreds:                        0

    Input bandwidth utilization threshold : 80.00%
    Output bandwidth utilization threshold: 80.00%
    Input bandwidth utilization  : 0.04%
    Output bandwidth utilization : 0.62%

The error Symbols: 529186 generate link flappings many times a day.

Ethernet RFCs describe how to place an L2 frame in the physical layer (L1), 8B/10B encoding process takes 8bit of Media Access Control Layer and converts it in a 10bit symbol to encapsulate it on the physical media.

When this error happens It means:

  1. You have CRC on fiber/copper cable because of a physical problem.
  2. The encoding process is not the same at both ends of the link.

If your link is good, something happened on the link. Almost surely a Media Converter has been added or removed. this action caused an anomaly in the transmission of symbols on a physical level.
To solve the problem it is necessary to renegotiate the ports of the link by setting them at a fixed speed, then shut and no shut will solve the problem forever.


.glitchlist crew

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