Re: (ASCEND) Full-Duplex on Max6000

["Julio Arruda" <jarruda@nortelnetworks.com>]

At 11:42 AM 3/17/99 +0000, Mike Hughes wrote...
>I was looking through the mailing list archives for a definitive answer 
>on this, and couldn't find one.
>
>Here's the score:
>
>Several Max 6000's running into Cisco Catalyst 2924/2916 
>switches.
>
>If the Catalyst ports are set to auto-sensing, I get 100Base-T half-
>duplex by default.
>
>If I force the Catalyst port into full-duplex, and reboot the Max, the 
>Max still comes up half-duplex, 99% of the time. Only once did one 
>of the Maxen correctly detect the full-duplex. Next time I reloaded 
>that box, it came up half-duplex.
>
>So, has anybody figured out how to get a Max6000 into 100Base-T 
>full-duplex reliably yet?

Sorry to jump in, since I'm not with cisco or ascend.

As with others vendors that support 802.3u autonegotiation, both parts should agree on the link capability, it is not a "sensed thing".

In several cases, as the standard say, if they can't autonegotiate (it would think is peer is a non-802.3u compliant), they can "sense" the speed, but not the duplex, so they (as the standard say) go to half-duplex.

The 100% safe way to have two boxes to use 100BaseT full-duplex is to have it fixed IN BOTH SIDES.

Otherwise, if you, let's say as a example, after the link was established with 100FD by the autoneg process, reboot the switch (in a Server NIC attached to a switch), the Server nic may forget to redo the autoneg stuff, and in this case, the NIC would be in 100FD and the switch, since didn't see any autoneg going on, goes to 100, but half-duplex (remember, it can "sniff" the speed, not the duplex).
I've seen cases where a 2 months old driver (in a xircom pcmcia nic) could not autoneg, and after loading a new driver, it works fine, so you may also want to check latest versions fixing autoneg probems.
[], <O-O>

Julio Arruda

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