Felice,
Doesn't look like my last message got through so
I'll try again.
Draw out 3 3524 switches running vertically
beneath each other as they would appear in a cabinet.
Label the first switch A, the middle switch B and the
Lower switch C.
Let Switches A,B and C contain 1 GBIC and give
switch A a fibre uplink to the core.
Now if switch A GBIC port 2 is patched to switch
B (GBIC port 1) as per reccomended by Cisco, you will
have 48 user ports that have access to the fibre core
without any contention for the GBIC link between A &
B.
However, when you add a 3rd Switch 'C', and GBIC
port 2 of switch B to port 1 of switch C then there is
contention for the GBIC link between A and B, and an
Ethernet Bus and collision domain is formed between A
& C.
HTH
Phil.
--- Felice Russell <[EMAIL PROTECTED]> wrote: > Hello
Phill,
> Thank you - can you explain the last part? The
> ethernet bus part? Actually I
> noticed late collisions on 2 ports. One is connected
> to the Cabletron and
> the cable is about 5 feet long. I have a feeling if
> I get the MMAC out of
> the picture that will help. I am not certain that
> the other port has a hub
> connected to it. I did some research last night and
> found that the problems
> traditionally would be 1) cable distance out of spec
> 2) too many repeaters.
> I also found that the late collision error shows up
> in 12.0 code when there
> is auto-negotiations problems. They are definitely
> having that.....
> Thanks so much
> Felice
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120
> t/sem120t.htm
>
> -----Original Message-----
> From: Phil Barker
> [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, July 20, 2000 12:50 PM
> To: Felice Russell; Cisco Groupstudy
> Subject: Re: Switch Limitations?
>
>
> I am presuming the late collisions are being
> detected
> on the cat 3500 connected to the HUB ?
> After checking that the cable distance between hub
> and
> cat switch is within limits try a spare cat switch
> (out of hours) in place of the hub and see if you
> still get late collisions if you do then look at the
> cable with a TDR etc, if not, replace hub with more
> 3524's. Be aware that connecting a 3rd 3524 via
> GBIC's
> causes the formation of an Ethernet Bus between the
> switches.
>
> Regards,
>
> Phil.
>
> --- Felice Russell <[EMAIL PROTECTED]> wrote: > Hi
> I
> have a question about switch configuration
> > limits- what i have are four
> > standalone cat 3500xl with gbic uplinks and one
> > cabletrom MMAC acting as a
> > backbone. There are two routers- one connected to
> > one network and the MMAC
> > and the other connecting to one of the cats. There
> > are several hubs hanging
> > off of the cat 3500 but none of them have hubs
> > daiseychained out- and there
> > are late collisions showing up on the catalyst. I
> > considered making the
> > catsa cluster but there are all sorts of crazy
> > protocols running aorund the
> > network as one of the routers is bridiging things
> > like dec and sna.
> > ANy ideas? Please help
> > Thanks
> > Felice
> >
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