| 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 looking at a RFI for a new campus, and have some items i need advise on. Background : 8 buildings, close together, backbone will be fiber optics using FDDI. Horizontal cabling will be UTP, sheilded TP, or hybrid. Concern : The campus would be opened 1994. Would FDDI be obsolete by then ? Issues : 1. FDDI is said to be unsuitable for terminal to host applications which are time sensitive. Comment ? 2. Comments abt the availability of FDDI over twisted pair and on the proposed LCF-PMD standard which allows FDDI to operate over low cost fibers. 3. FDDI-II will probbaly end up connecting to PBX and ISDN equipment. Comments on how FDDI-II will support or enhance ISDN ? 4. FDDI-II may operate at 600 Mbps instead of the current 100Mbps. Comments on the possibility ? 5. Network mngt is an emerging std. Comments on the Station Mngt (SMT) std which is expected to be adopted in 1992 ? Rgds, Mike
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 678.1 | KONING::KONING | Paul Koning, A-13683 | Fri Aug 21 1992 12:58 | 29 | |
No, FDDI will not be obsolete in 1994. It will be a solid standard with products available from many suppliers. 1. FDDI async service has pretty good response time; under reasonable loads the latency should be a millisecond or less, assuming the network isn't very large. If you are worried about behavior under extremely high load (what I would generally call "serious overload") then sync service can be used. I've done some work with a large customer who is planning to use FDDI for factory process control, and has done a lot of work studying the latency issues. They seem satisfied that this can be done right. 2. Did you look at earlier notes on this? 3. There are fewer and fewer people who still believe that FDDI-II will ever amount to anything. I certainly don't. It's stated purpose doesn't make much sense. Note that FDDI-II is INCOMPATIBLE with FDDI, in spite of what its fans want you to believe. 4. No, FDDI-II runs at the same raw data rate as FDDI, and then it takes away some of that for its other functions. So it is at BEST slightly slower, and at worst a LOT slower. It's also very much more complex and the standard is not even close to being finished. 5. SMT (for FDDI, not for FDDI-II) seems to be pretty much done as far as technical issues goes. Implementations of the earlier draft (6.2) are shipping from a lot of suppliers and work well. paul | |||||
| 678.2 | GIGAswitch strengthen FDDI | BONNET::LISSDANIELS | Tue Aug 25 1992 17:28 | 15 | |
With our GIGAswitch that was program announced at DECworld there is enough flexibility to ensure that FDDI rings can be kept at sizes that will not cause delays. With GIGAswitch you will have the choice to configure FDDI as "large" rings for small systems/PCs and smaller rings for mid size systems. Dedicated FDDI for large systems and Full Duplex FDDI (100Mb/s both directions) for Digitals large systems. And prices for the GIGAswitch will NOT be terribly high... No FDDI will not be obsolete in 1994 or soon thereafter. Torbjorn | |||||