Trevor, have you had similar experiences connecting through a Catalyst 5000
switch?  Any information relevant to this infrastructure configuration?

Thanks much, as always!        Bonnie






Trevor.Foley AT BANKERSTRUST.COM DOT AU on 10/22/97 04:20:12 PM

Please respond to ADSM-L AT VM.MARIST DOT EDU

To:   ADSM-L AT VM.MARIST DOT EDU
cc:    (bcc: Bonnie Goins/Headquarters/USX)
Subject:  Re: Fast Ethernet, CISCO Catalyst Switches, and ADSM




> Our company is in the process of changing from a FDDI backbone to a
> switched network using CISCO Catalyst switches. We are currently
utilizing
> dual FDDI adapters in our eight RS/6000's. We are running AIX 4.1.4 on
all
> of our RS/6000's and ADSM 2.1.5 on our R40 that has four SCSI 3590-B1A
tape
> drives in a 3494 Tape Library that is serially connected to the R40
server.
> We are backing up numerous clients including, RS/6000, SUN, Novel,  NT
and
> AS/400.
> Dare I ask if there any issues or potential problems we might encounter
??

Wayne,

You probably don't want to hear this, but from my expericence, you may well
suffer performance degredation with this conciguration change.

With fddi, you are able to set the maximum transfer unit (mtu) to up to 4k.
With ethernet (whether it be fast or any other kind), the biggest that mtu
can be is around 1536 bytes. And ADSM seems to be very sensitive to the
size of mtu.

We had one instance where we increase mtu from 512 to 1536 bytes and the
throughput went up by almost 3 times, showing an almost direct
relationship, in this case, with mtu size and performance.

That being said however, we do have fast ethernet (we have a mix of fddi
and fast ethernet) clients able to backup up to 10 gb/hour.


regards,

Trevor