I have been struggling for a while with port speed / duplex mismatches between a Billion 7800 and Cisco 2924.

The basic problem with the Billion is that neither the web interface nor the available telnet commands allow media configuration of LAN switchports i.e. unable to force speed / duplex settings.

I have found a way to change the setting, but it doesn't persist through reboots. Does anybody know how to achieve a persistent change?

The steps to make the change for those that are interested are as follows:

  1. Telnet into the router in the normal way
  2. Start a [busybox] shell

  3. Use ethctl to configure the switchports:

    /bin/ethctl eth1 media-type 100FD port 3


  1. The ports are numbered in reverse compared to the box labels (i.e. interface labelled '1' is port 3, interface labelled '4' is port 0).
  2. As an aside, once you've run the BusyBox shell the router filesystem and standard commands are available - this is useful compared to the somewhat restricted default interface.
  • There is no reason that wiring should cause autonegotiation to fail. Fast Ethernet negotiation does not rely on any of the other pins. I suspect you have some kind of serious wiring problem -- perhaps the wiring are mismatched onto the twisted pairs. Nov 1, 2011 at 3:55
  • David - the wiring is fine, and can confirm that autonegotiation is working. My error on the 2 pair causing autoneg to fail (I recalled reading this somewhere but should have verified). I have removed this from the question.
    – paulkmoore
    Nov 17, 2011 at 12:23


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