| 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 |
The EOM customer will use TCP/IP for a Military End user
A subset of redondancy configuration will be
+---------------------------------+
I +-----------------------------+ I
I I I I
I I FDDI I I
I I 2 * DECconcentor500 I I
I I ___ ___ I I
I +----+ +---------+ +------+ I
+------+___+---------+___+--------+
I I I I
+---+ I I +------+
I I I I
I +-----------I-----+ I
+-+--+ I ++--++
I +--------------+ I I
+----+ +----+
DS5000/200 DS500/200
Do you agree with my solution ? I hope so.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 163.1 | KONING::KONING | NI1D @FN42eq | Mon Oct 29 1990 18:23 | 65 | |
That should work, if TCP/IP supports multiple adapters. (I don't know the
answer to that.)
You have basically created a single network with each node attached twice
to the network. An Ethernet equivalent would be:
------------------------------------------------------------
| | | |
--------- ---------
| | | |
--------- ---------
While this is fine, a disadvantage is that you are protected only from
failures of the adapters (and of the concentrator, in the FDDI case you
showed) but NOT from problems that bring down the FDDI as a whole.
With the same amount of hardware you could also build two separate LANs.
The Ethernet analog would be:
------------------------------------------------------------
| |
--------- ---------
| | | |
--------- ---------
| |
------------------------------------------------------------
which on the FDDI translates to:
+---------------------------------+
I +-----------------------------+ I
I I I I
I I FDDI I I
I I DECconcentor500 I I
I I ___ I I
I +----+ +--------------------+ I
+------+___+----------------------+
I I
+---+ I
I I
I +-----------------+
+-+--+ ++---+
I +----+ +------------+ I
+----+ I I +----+
---
+----------+ +------------------+
I +--------+___+-----------------+ I
I I I I
I I FDDI I I
I I DECconcentor500 I I
I I I I
I +-----------------------------+ I
+---------------------------------+
I've shown the dual ring with just one concentrator in it. You wouldn't
normally do that, of course (if that's all you have you would simply omit
the A/B connections completely and have just a tree). But if you add
more concentrators you would get them in pairs, one for each FDDI LAN.
In this example you have two completely separate LANs. Any of the various
conditions that can break an FDDI LAN will now affect only one of them, so
you still have the ability to communicate on the other.
paul
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