I wanted to mention that we've been in the process of upgrading our
switches, as well, and I discovered that since we've started using the new
Cisco switches we've been having all sorts of problems getting the speed and
duplex settings set correctly.

We've discovered that if you have relatively new NICs with updated drivers,
set both sides to AUTO. Never, ever, set only one side to AUTO.  I'd also
avoid manually configuring the speed and duplex unless you have to do so to
fix a specific problem.  Here's why:

There is no standardized behavior for 100BaseTX when you manually configure
settings!  The only setting mentioned in the specification is AUTO; the
behavior of the NIC with any other setting is up to the vendor and not
everyone handles it the same way.  Cisco appears to have changed the way
they handle it, which is the cause of a lot of our problems.

If you hard-set the speed and duplex there are two ways to handle this:

1.  Use the configured settings and still participate in autonegotiation
only offering the configured settings.

2.  Use the configured settings and do not participate in autonegotiation

Cisco's new switches seem to use option #2, while a great number of our end
devices use option #1.  Why is this a problem?  Here's what happens when you
connection an option #1 device to an option #2 device:

#1 participates in autonegotiation, only offer the configured settings.
#2 does not participate in autonegotiation at all and will forcefully use
the configured settings.
#1, seeing that there's nothing on the other side using auto assumes it is
connected to a HUB, and just might set itself to 10/Half regardless of the
manually configured settings!

As you can guess, this is bad mojo.  The moral of the story is that you
should try to start using AUTO on BOTH sides if you're using newer Cisco
switches, in particular the 2950 series.  In some cases this won't work and
you'll have to resort to manual settings.

HTH,
John


>>> Priscilla Oppenheimer 3/10/03 10:58:56 AM >>>
Mike Momb wrote:
> 
> To all,
> 
> We recently replaced our Nortel switches and routers with Cisco
> 2980 switches and 6509 routers.  We have two buildings, 10
> floors each and a router in each building.  We have a
> combination of NT and Novell servers.   After replacing all
> this equipment, we have noticed that when we access files on
> the NT servers, the speed is acceptable.  When we access files
> on the Novell servers, it is very very slow.  Could the
> switches or routers be configured incorrectly for IPX.  Is
> there something that we can change.  On Cisco's web page it
> mentioned something about enabling ipx
> broadcast-fastswitching.   Any input or comments would be
> appreciated.

I doubt that ipx broadcast-fastswitching will help you unless you are using
an ipx helper-address. With ipx helper-address (just like ip helper-address)
you can tell a router to forward a broadcast, which it normally doesn't do.
This would be useful for some rare IPX application that sent broadcasts that
needed to reach the other side of the router. In typical IPX networks,
there's no such need. When there is a need, you can speed it up with the ipx
broadcast-fastswitching command.

You titled your message "10 half or 100 full." I think this was a Freudian
slip. I bet your problem is related to a full-duplex mismatch. Perhaps the
NICs in the NT servers negotiated correctly but the NICs in the Novell
servers did not and you have a mismatch.

With a mismatch, the full duplex side will send whenever it wants. The half
duplex will get upset if it sees the other side sending while it is also
sending and will backoff and retransmist, leaving behind a CRC-errored runt.
That side will reports a collision. The other side will report runts and CRC
errors.

So, look for lots of Ethernet errors when you do a show int or show port.

Also feel free to send us the output of various show commands and your
router config. There are some IPX gurus on this list.

_______________________________

Priscilla Oppenheimer
www.troubleshootingnetworks.com 
www.priscilla.com 



> 
> thanks
> Mike




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