| 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 |
My customer is moving to FDDI in order to consolidate about 40 different
Ethernet segments inside one building. They want to know what effects
FDDI will have on their custom Ethernet code. Here is a simplified
view of their current configuration:
A B K L
+---+ +---+ +------+ +---+ +---+
|VAX| |VAX| . . . |Bridge| . . . |VAX| |VAX|
+---+ +---+ +------+ +---+ +---+
||| ||| | | ||| |||
---o||---o||------o-----------o+ +o--------------------o||---o||---
----o|----o|-----o|---------+ | | +-------------------o|----o|---
-----o-----o----o||------+ | | | | +-----------------o-----o---
||| | | | | | |
+---+ | | | | | |
|VAX| 1 2 3 4 5 6
+---+ Ethernets
C
Nodes A, B, and C are in one area and nodes K&L are in another area.
Software on nodes A&B communication with software on nodes K&L via
a customized protocol. The custom code makes QIO calls to the Ethernet
driver and specifies address and data to be transmitted. Node C is a
network monitor with Ethernet adapters that operate in permiscuous mode
to monitor Ethernet traffic.
They want to migrate to FDDI one area at a time. Proposed configuration:
A B C
+---+ +---+ +---+
|VAX| |VAX| . . . |VAX|
+---+ +---+ +---+
| | |
| | |
+--+ +--+ +--+
=====|WC|=====|WC|=====|WC|===== FDDI ring
+--+ +--+ +--+
|
+------+
|Bridge|
+------+
|
-o----------o-----o------------ Ethernet 4
| |
+---+ +---+
K |VAX| |VAX| L
+---+ +---+
| | | |
-------------o-|---o-|----------------- Ethernet 5
------------o-----o---------------------- Ethernet 6
I read in the I/O User's Guide that LAN drivers (Ethernet and FDDI)
support the same QIO interface, and that the six-byte Ethernet address
is also supported by the FDDI driver.
Questions:
1. How much impact will FDDI have on the custom protocol code
on nodes A&B?
2. Is there a permiscuous mode in FDDI that allows a network monitor
to collect all messages?
This note also filed in the MOUSE::ETHERNET conference.
Thanks
Tim
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 906.1 | expect no problems | STAR::GAGNE | David Gagne - VMS/LAN Development | Tue Mar 23 1993 18:44 | 10 |
They should have to do nothing but have their custom program use the
FDDI device. The default value for all new FDDI features make FDDI
compatible with Ethernet.
There is a promiscuous mode on FDDI.
One area of difference in FDDI vs Ethernet is that the default physical
address on FDDI is ALWAYS the hardware address. For Ethernet, the
default address is the current address (if there are users) or the
hardware address (if there are no users).
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