| 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 |
In order to utilize FDDI on a realtime project, we need the following basic figures: 1- suppose 2 Decsytems5000/200 linked together with FDDI. What's the minimum time to transfer a small message -say 64 bytes- from one machine to another? (we suppose here that programmation is done at the lowest level -MAC level- ) We know that for an Ethernet connection this time is 4 millisecondes. 2- Suppose we have 4 DECsystems5000/200 connected through FDDI. Each systems read a message and send a message when it gets the token. The message can be supposed to have the maximum size -4000 bytes approximately-. What's the time interval for 2 messages emitted by the same machine? These 2 situations are not of course realstic situations but these numbers enable Realtime people to estimate the behaviour of their systems in the worst cases and so to put the right limitations (number of systems, number of bridges and soon). Thanks for helping. Soumetty.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 154.1 | Benchmark time | KONING::KONING | NI1D @FN42eq | Mon Oct 29 1990 17:57 | 8 |
You should probably do some measurements in typical configurations. So long as the load on the FDDI is reasonable, the access delay should be quite short, so the question basically is how long it takes to do the I/O operation. Incidentally, how did you come up with the 4 ms number for Ethernet? That number has NO connection to reality. paul | |||||