Re: Ethernet NIC dual homing

Dan Hollis
2001-10-30T04:55:20Z

On Mon, 29 Oct 2001, Jonathan Lundell wrote:
> At 6:33 PM -0800 10/29/01, Dan Hollis wrote:
> >On Mon, 29 Oct 2001, Christopher Friesen wrote:
> >> Are there issues with using MII to detect link state? I thought
> >>it was fairly
> >> reliable...
> >It doesn't work to detect link state through bridging device (say, bridged
> >ethernet over T3). The T3 might go down, but your MII link to the local
> >router will remain "up", so you will never know about the loss of link and
> >your packets will happily go into the void...
> ARP isn't going to do much for you once the failure is beyond the
> local segment, is it?

But you can use it to determine end-to-end link status. MII is useless for
that when you're going through a bridge.

So ARP is *perfect* for this situation and is *exactly* what is needed.
When you determine link is down using end-to-end status like ARP then you
can take the device out of the bonding queue. Presto, 100% perfect
failover.

-Dan
--
[-] Omae no subete no kichi wa ore no mono da. [-]