| 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 |
I am working with a group who is going to supply a FDDI solution to the
government. For reasons not needed to be discussed here, they are
going to use VAX 4400 Qbus systems with the DEC FDDI Qbus card.
I have 2 performance concerns, as follows:
1. The Qbus is about a ~25Mbps bus... right? The concern here is
obvious.
2. Can a VAX 4400 even run at 10Mbps, much less the speed of the Qbus?
I haven't had any luck in Notes conferences hunting any of this down.
I am just looking for some "real time" experiences with FDDI on Qbus
systems.
Thanks,
Mark
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 1377.1 | NETRIX::thomas | The Code Warrior | Tue Jun 14 1994 16:34 | 1 | |
You may barely achieve 3MB/s if you are lucky. | |||||
| 1377.2 | KONING::KONING | Paul Koning, B-16504 | Wed Jun 15 1994 10:55 | 13 | |
Qbus should allow performance higher than that of Ethernet, but not nearly up to raw FDDI rates; the bus simply isn't up to it. If the customer wants Qbus for whatever reason, and needs FDDI, but doesn't need speed significantly in excess of Ethernet speed, then this should be ok. If the requirement is for "full FDDI" speed, then another bus MUST be used since Qbus can't do that. As usual, the best answer is to run a benchmark that's representative of the application(s) to be used. The bus is likely to be a big issue, but there may be other system issues that reduce throughput further. paul | |||||