1 Reply Latest reply on Jun 5, 2012 6:43 AM by novethdevera

    Orion shows 3750 port speed changes - is it normal?

    WiKciD

      Hi all,

        We use Orion for monitoring.  We recently started monitoring a workstation switch and find many occurances of port speed changes indicated.  Our workstation ports are configured with auto speed and duplex.  Is it normal that we are detecting speed changes on the ports?  Do workstations running XP automatically adjust their speed for traffic management or power save?  Perhaps something like speeds changing when PC goes to sleep mode but has wake on LAN enabled?  Is it possible that the MIB is misreporting?

       

        I realize that there are many different NIC vendors/drivers that might act differently.  Just wondering (in others experience) if it is somewhat normal or if there is anything on network I should be looking into as to why speeds are changing?  We plan to not monitor workstation ports (only uplinks) on the switch.. but before we do, I thought I would see if what we are detecting needs to be addressed?

       

        Here is an example from Orion of a speed changing.  Seems always off hours:

       

      6/1/2012 6:17:52 AMeventWoRKSTATION-3750-CLUSTER - GigabitEthernet1/0/14 · 2nd Floor Patch#11 Interface Speed changed from 10000000 to 1000000000 bps

       

      6/1/2012 2:47:52 AMeventWoRKSTATION-3750-CLUSTER - GigabitEthernet1/0/14 · 2nd Floor Patch#11 Interface Speed changed from 1000000000 to 10000000 bps

       

        Thanks in advance for any experienced feedback.

       

      --

      Colin

        • Re: Orion shows 3750 port speed changes - is it normal?
          novethdevera

          Hi Colin,

           

          I too have wondered why that is happening before so I checked the switch itself and here's what I found out: when an interface is down, for example a FastEthernet port, recall that a FastEthernet port can be 10 or 100 Mbps depending on the device connected to it, it seems that when a FastEthernet port is down, it's default speed is 10 Mbps only. Go check the interface status of your GigabitEthernet1/0/14, if it is down, you will probably see:

           

          GigabitEthernet1/0/14 is down, line protocol is down

            Hardware is Gigabit Ethernet, address is 0023.0444.ca0b (bia 0023.0444.ca0b)

            MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec

           

          See, the bandwidth is 10 Mbps only when it is down.

           

          Hope that I have helped you.

           

          Thanks!