5 Replies Latest reply on Jan 27, 2015 7:02 AM by corey

    Speed / Duplex Mis-Match Question

    michael_jones New Member

      I have recently started to see a speed duplex mismatch when ssh'd into my Netvanta 3120.


      The message is:

      2012.02.20 13:09:29 LLDP LLDP:  Speed Duplex mis-match on swx 0/1. Speed/Duplex: "100M/full-duplex"   Neighbor Speed/Duplex: "10M/half-duplex"


      I have nailed up both ends at 100M/Full-duplex and I am still seeing the warning.


      This port (swx 0/1) is plugged into my switch a (Netgear GS724T ; firmware V1.1.4(0618)) .


      Does anyone have any suggestions?


      Thanks in Advance


        • Re: Speed / Duplex Mis-Match Question



          Could you reply with the configuration for interface switchport 0/1? Also, which firmware is the NetVanta 3120 currently running?




            • Re: Speed / Duplex Mis-Match Question
              michael_jones New Member



              ! ADTRAN OS version

              ! Boot ROM version

              ! Platform: NetVanta 3120, part number 1700601G2


              sh interface sw 0/1


              swx 0/1 is UP, line protocol is UP

                Hardware address is 00:A0:C8:72:A3:CD

                100Mb/s, full-duplex

                output flow control is disabled, 0 pause frames sent

                input flow control is disabled, 0 pause frames received

                ARP type: ARPA; ARP timeout is 20 minutes

                Last clearing of counters never

                5 minute input rate 142896 bits/sec, 67 packets/sec

                5 minute output rate 551296 bits/sec, 76 packets/sec

                  Queueing method: fifo

                  Output queue: 0/256/0 (size/max total/drops)

                  Interface Shaper: NOT ENABLED

                  1513111 packets input, 279146394 bytes

                  1478439 unicasts, 18154 broadcasts, 16518 multicasts input

                  0 symbol errors, 0 discards

                  0 input errors, 0 runts, 0 giants

                  0 alignment errors, 0 crc errors

                  2025960 packets output, 2048509982 bytes

                  2007113 unicasts, 8018 broadcasts, 10829 multicasts output

                  0 output errors, 0 deferred, 0 discards

                  0 single, 0 multiple, 0 late collisions

                  0 excessive collisions


              sh run (for sw 0/1)


              interface switchport 0/1

                speed 100

                no shutdown


              sh switchports


              Name: swx 0/1

              Switchport: enabled

              Administrative Mode: access

              Negotiation of Trunking: access

              Access Mode VLAN (configured): 1

              Trunking Native Mode VLAN: 1

              Trunking VLAN Enabled: 1-4094

              Trunking VLAN GVRP Fixed: none

              Port Expiration: disabled

              Port Security: disabled

                • Re: Speed / Duplex Mis-Match Question



                  I didn't see any issues in the configuration  or statistics you sent of the NetVanta 3100. If there is a true duplex mismatch, more than likely you will see collisions and/or input errors on either side of the link. I did not see any on the NetVanta 3100. Generally, the rule of thumb regarding speed and duplex settings is that if the device the NetVanta is plugged into is set to auto-negotiate, then the NetVanta should also be set to auto-negotiate. If the device the NetVanta is plugged into is hard-set to a certain speed and duplex setting, then the NetVanta should be set to the same speed and duplex setting as the device.


                  It would be helpful to see the output of "debug lldp verbose" on the NetVanta 3100. Simply, telnet to the NetVanta, get into enable mode, and issue the "debug lldp verbose" command. It would be a good idea to log the output as the data maybe displayed faster than you'll be able to review it. To disable the debug, simply type in "u a". This will help us in seeing what the Netgear is telling the NetVanta via LLDP regarding its own speed and duplex.


                  Another option that would possibly provide more information is to set up a port mirror between the 3100 and the Netgear and capture the LLDP traffic between the two.


                  If you are able to get any debug, I would be more than happy to take a look at it for you.




              • Re: Speed / Duplex Mis-Match Question

                As an update, in R10.11.0 AOS, a switchport command was added that allows an AOS switch the ability to ignore these LLDP speed-duplex mismatch messages.  If you add the command "no lldp receive 802.3-info mac-phy-config" to any applicable switchports, the switch will no longer log every LLDP update indicating a mismatch as an event in the event-history.