| Title: | FDDI - The Next Generation |
| Moderator: | NETCAD::STEFANI |
| Created: | Thu Apr 27 1989 |
| Last Modified: | Thu Jun 05 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2259 |
| Total number of notes: | 8590 |
I have a customer with a question - can anyone help ?
I don't know what the Green book is ?
Is STP an industry or proprietary standard?
Thanks,
Dave McCallum.
I have a few questions about low level FDDI over STP problems. We have DEC 500
and Interphase 1600 concentrators. We also have STP Sparc cards from Interphase
(4611) and NPI and our own FDDI product.
When the Interphase card is connected to the DEC concentrator or the NPI card
to the interphase concentrator the link fails. The Interphase end indicates no
signal detected and the other end fail to establish a link. Our own STP cards
connects successfully to both concentrators.
Since fibre works in all combinations I assume this is not a SMT problem. It
has been suggested that one produce is using SDDI and one the Green Book
standard.
Has this problem been observed before ?
Is there a solution ?
Thanks, in advance, for any help
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% From: [email protected] (John Tricker)
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% Subject: Request for help on STP FDDI incompatibility
% To: [email protected], wellin::mccallum, [email protected] (Stelios Pavlides), [email protected] (John Tricke
% Date: Thu, 14 Oct 1993 17:18:39 +0100 (BST)
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| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 1116.1 | LEVERS::THOMPSON | Fri Oct 15 1993 12:26 | 17 | ||
There are presently more than one implemtation of FDDI STP in the
market. One is the so called Green book standard. Why green? I don't
know other than maybe the first cover of the first draft copy was
green. This standard was put together by five or six companies. I
don't recall all of the companies but DEC, Synoptics, Motorola were
some of the companies.
The other standard you refer to was SDDI. I think what you really mean
is CDDI. Crescendo is the creater of CDDI. CDDI is not compatible
with the Green book standard. I'm not sure what Interphase but I'm not
surprised you are having problems.
The good thing is that a standard for copper FDDI has emerged from the
ANSI committee that will be a true standard. As true as standards get.
Products built to this standard should be available in the near future.
Bruce.
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| 1116.2 | Some additional clarification on STP | LEVERS::B_CRONIN | Mon Oct 18 1993 11:16 | 22 | |
There are many proprietary STP FDDI systems right now. The Green
Book is the one that Digital helped develop, and it is the basis for
our 150 ohm (i.e. type 1 and 2) STP product set.
IBM chose not to support the Green Book STP document, and developed
a proprietary system of their own, which they called SDDI. They got
support from many companies for this. It DOES NOT interoperate with
the Green Book document.
CDDI refers to Cresecendo Communications implementation of FDDI on
copper. It is usually used on 100 ohm category 5 UTP cables; I am not
sure whether it supports STP or not. Crescendo was recently purchased by
cisco systems, and now does business under the cisco name.
Finally, as Bruce pointed out, the ANSI standard is pretty close
to completion. That standard will support category 5 UTP and 150
ohm STP. It will not interoperate with all of the other things out
there today. If all goes well the standard will go to ballot in
December.
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