| 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 |
A couple of brief questions???
I would like to know if Fiber Optic bypass is implemented in
the DECconcentrator. The idea being, should there a lost of
power to the concentrator, would the primary light source be
maintained (Bypass) or would the stations on each side go into
fault recover mode and close the loop using the secondary ring.
What revision of the SMT spec. is implemented in Digital FDDI
product set?? I've heard 5.1.. Also, Is there a later revision
available which other vendors might be implementing.
Any assistance would be appreciated..
Later,
Ray
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 124.1 | a couple of brief answers | LEVERS::CIARFELLA | Saabless and happy | Mon Aug 27 1990 10:14 | 9 |
The DECconcentrator does not contain a bypass relay.
Currently, our products are shipping with SMT 5.1. SMT 6.2 is
now being field tested and should be released for general consumption
sometime this fall. I'm not sure what the current target date is.
Paul C
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| 124.2 | A little more info | AKO569::JOY | Get a life! | Tue Sep 04 1990 16:39 | 9 |
Ray,
Instead of optical bypass relays we implement the "wrap"
electronically to repair a break in the ring. Bypass relays can cause
problems if by actuating them they now produce a link longer than the 2
km max. interstation distance or produce a loss greater than 11 dB in
any one link.
Deb
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| 124.3 | Article reference | NSCRUE::KNIGHT | Thu Oct 18 1990 19:31 | 16 | |
I would highly recommend an article written by Jim Kuenzel, Anand Parikh, and
James Marsh (all from DIGITAL) for the rationale for not using optical bypass.
It concludes, "The inclusion of relays in the network means added cost of
components and connectors, loss of optical power, reduction in interstation
distance, and an additional failure mechanism. These factors limit the use of
such relays to very small workgroup LANs - typically up to 10 stations - and
make the relay an unattractive solution for a large network environment."
It is in "Telecommunications" (I have the "North American Edition"), October
1989. The title is "FDDI Dual Ring of Trees Topology."
This is an excellent initiation to the overall design philosophy we followed
in our FDDI products. I think anyone selling our FDDI approach should read it.
Paul Knight
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| 124.4 | ZPOVC::HWCHOY | It must be Thursday. | Thu Oct 18 1990 22:39 | 4 | |
And would any of our three amigoes have a copy of the source online?
Nevermind if it's not pretty :)
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