SUMMARY: Ethernet problems.

From: Jan v Doorn (
Date: Fri Jul 10 1992 - 04:19:49 CDT

Hi Sun Managers,

Some time ago I posted a question about problems using a (compatible) Sparc
and the DECrepeater 90T. I got several replies, and Gary Richardson's advice
to swap the motherboard fixed the problem. There was some discussion about
Sparc's being very aggressive in their ethernet access, and the DECrep not
being able to handle that, but consensus is that although SPARCstations may
be near the limit, they are according to specs.

Anyhow, thanks to: (Barry B. Reinhold)
 "John Paul O'Brien" <> (Gary Richardson)
 Casper <>

Here is the original query:
>>Hello Sun managers,
>>We are experiencing the strangest problems with one of our workstations
>>(a GSStation, a SS2 compatible, furthermore referred to as SS2), and I
>>was wondering if anybody could shed some light on this matter.
>>We have an UTP network with a DEChub90 and for ethernet DECrepeater90T's,
>>which is perfect for all our DEC equipment, terminal servers, SS1+'s
>>IPX's, etc, but it's not possible to use this SS2 in this network.
>>The symptoms:
>>When transferring files > 150 kBytes from the SS2 to any other station/
>>system, the process transferring the data will hang (this can be nfs, ftp,
>>lpr, etc). Some experimenting showed this is only when using DECrepeater
>>90T's. Thickwire, Thinwire, and UTP directly do not have any problem
>>The situation:
>> ______ ______
>>| | | |
>>| SS2 |-________________ ___________________-| IPX |
>>| |- UTP | | UTP _| |
>>|______| _|____|_ |______|
>> |DECrep |
>> | 90T |
>> |________|
>>More info:
>> - We use lantronix LTX-T or DEC h3550 transcievers to convert the AUI
>> to UTP; both have the same problem.
>> - the tests were done in a seperate network environment, no other
>> systems but the two systems in the diagram were involved.
>> - Thinwire, Thickwire, and UTP without the DECrepeater90T work fine,
>> but it also works if I put a bridge between the SS2 and the 90T.
>> - We have no network analyzer to sort this out...
>> - The IPX will have errors at the same rate it's receiving packets in
>> the perfmeter (how can I see what errors these are ?).
>> - The IPX will create an empty file, and that's it.
>> - Swapping the DECrepeater90T doesn't make any difference.
>>Is the SS2 too fast for our DECrep's (doesn't follow the ethernet spec?) ?
>>Any help would be greatly appreceated!
>>Jan van Doorn
>>Thijssen BV, Veenendaal, Holland.
>>+31 8385 35111,

Jan van Doorn 
Thijssen BV, Veenendaal, Holland.
+31 8385 35111,

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