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Fletcher_Cocquy's avatar
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May 14, 2012

BigIP 3400 nics negotiating down to 100Mb?

Our 3400's are several years old - but we are running recent (10.2.1) code.



We're trying to explain why the 1Gb nics are running at 100mbit - has anyone seen this before?


(The switch ports were checked and verified to be 1Gb ready)





6 Replies

  • George_Watkins_'s avatar
    Historic F5 Account
    Hi Fletcher,



    You've likely got an auto-negotiation issue. I would verify a couple of things:



    1. First things first, make sure you have good patch cables. Gigabit ethernet needs all 8 wires (4 pairs) to link at a gig.


    2. Verify that the BIG-IP is set for auto-negotiation (this is the default setting): SOL7612: Configuring the media speed and duplex settings for network interfaces


    3. If you've got good cables and auto-negotiation correctly configured on the BIG-IP, then you'll need to look at your switch.



    Hope that helps,



  • I agree with what watkins, though I would start by comparing the speed/duplex on both sides - the switch and the LTM. At first glance, it sounds like one side is set to auto an the other is set to 100mbit.
  • Hi Fletcher,


    Were you able to resolve this what was the problemm... ????
  • I've seen this in the past with hard-coded duplex settings one one side vs. auto on the other. But I don't know if I've seen this on 1G copper before...



    Anyhow, may be worth confirming either way.



    -- Matt
  • yes - after the network admin triple checked the switch ports were set to 100.


    We suspect this was to work around some autonegotiate issues in the past.


    Anyway, he set them to 1gb and its working fine now.