| 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 |
Hi,
Does anybody know is there any functional restrictions to
configure two DEFXS-AA SMF PMDs on DECconcentrator 900's
ports 1 and 6? Slots next to them will be empty so there
will be room for a class fiber loop.
I have read official recommendation that there should be
only one DEFXS-AA on a DC900. Why only one if we have
empty slots beside slots 1 and 6??
The customer need is to have dual ring FDDI between two
DC900s using SMF.
I know that new DEFXS-BA will come out in the near future
but we need this now.
regards
Jarmo
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 1536.1 | NETCAD::STEFANI | Look Ma, I'm drinking my oatmeal! | Wed Dec 28 1994 09:01 | 16 | |
>>I have read official recommendation that there should be
>>only one DEFXS-AA on a DC900. Why only one if we have
>>empty slots beside slots 1 and 6??
>>
>>The customer need is to have dual ring FDDI between two
>>DC900s using SMF.
I don't work in the DEChub group, so take my comments with a grain of
salt, but I don't know why there would be a restriction like that. We
never had a similar restriction in the DECconcentrator 500 series.
The customer configuration you're mentioning sounds reasonable to me,
but hopefully someone closer to the DECconcentrator 900MX can provide a
more definitive answer.
- Larry
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| 1536.2 | It's OK | NETCAD::SLAWRENCE | Wed Dec 28 1994 10:01 | 10 | |
[I do work in the DEChub group :-)]
In an early version of the installation guide it did say that you could
only use 1 single-mode PMD because there was some question at that time
about restritions on the internal air flow. Subsequent thermal testing
showed that this was ok. If you're willing to give up the three
adjacent slots you can use 3 single mode PMDs in a DECconcentrator
900MX.
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| 1536.3 | How many DEFXS-AA in a box = Heat or Space | YUPPY::GOODE | London TCC | Mon Feb 13 1995 14:42 | 21 |
Hi,
If it's Ok to put 2 x DEFXS-AA in a DC900MX, can you do:
SM/MM/MM/MM/MM/SM without any heat problems?
I have CAREFULLY installed a DC900MX like this and not exceeded SM bend
radius etc. and the module tested OK in a DEChub900MS.
Basically, is the requirement to leave a spare PMD slot adjacent to the
SM PMD for reasons of heat, or for fiber space/bend problems?
Thanks for any help...Es
P.S. I'd like to complain bitterly that this installation restriction
is not explained earlier in other sales/design guides, but has to wait
until we get the DC delivered to find out!
Network topology takes a lot of design & planning which we can't afford
to change at the last moment! This applies also to the kind of
fibre connectors that are going to be supplied with SM PMD's. This
causes expensive cables to be re-ordered if you don't know until the
PMDs get on site.
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