| 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 |
If I have an environment where the fiber can not be installed in a ring
and the return path is greater than 2Km, can I configure a concentrator with
two DEFCN-MF modules and NO DEFCN-NF module to act as a repeater?
1.5Km 1.5Km
______________________ _______________________
/A B\ /A B\
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1: |CON| 2: |CON| 3:|CON|
----- ----- -----
B\______________________/A B\_______________________/A
If there was a need for some SAS ports at location 2 then a second
concentrator would be necessary.
-----
2a:|CON|
-----
______________________/ \_______________________
/ \
----- ----- -----
1:|CON| 2b:|CON| 3:|CON|
----- ----- -----
\______________________/ \_______________________/
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 103.1 | KONING::KONING | NI1D @FN42eq | Sun Aug 12 1990 23:17 | 25 | |
NO, you can only have a single management board per concentrator.
However, the problem you're trying to solve goes away once you
configure the sort of topology that's preferred anyway!
You should (with a few exceptions) NOT run the dual ring "all over the
place". Read the discussions about "structured" wiring in the
DECconnect books and elsewhere. Use a hierarchy, either a single tree
with the root concentrator in the MDF (main distribution frame) or a
ring of trees with all the root ring concentrators in the MDF. In
other words, the dual ring does NOT leave the MDF. If you take that
approach, then the location in the middle of your picture is the MDF,
and the other two locations are IDF (intermediate distribution frame).
The IDF concentrators are connected to M ports of the MDF
concentrator(s).
The "few exceptions" I mentioned above concern situations where the
customer is worried about destruction of the entire MDF (say by fire).
In that case, it makes sense to have what you might think of as a
"split MDF" -- a dual ring of trees with half the concentrators in one
spot and half in another, and the lower levels of the hierarchy
connected redundantly to both MDFs. However, I suspect that's not
going to be a particularly common case.
paul
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