| 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 the recently announced DECconcentrator 500 dual Homing, I could read: Dual Homing is a mechanism that enhances fault tolerance of an FDDI network ... If either the active link or the concentrator 2 fails, the standby link will automatically activate, and concentrator 3 will still be connected to the FDDI ring, now via concentrator 1. Questions: All 3 concentrator have the same MTBF, so what is the actual benefit of dual homing. Enhancement = ..% bigger MTBF ! What about the fact that all our FDDI connection are SAS ! If they fail, that's the end anyway ! Walter.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 147.1 | Dual-homing is GOOD | AKO569::JOY | Get a life! | Tue Oct 02 1990 14:43 | 12 |
The point is that if you have a cascaded concentrator with several
systems or Ethernets hung off of it and the upper level concentrator
fails you lose everything from the concentrator below it (i.e. all
systems and Ethernets). If you have the cascaded concentrator
DUAL-HOMED to an alternate upper level concentrator, now you have a
backup path to the backbone if the primary concentrator fails.
As for the MTBF issues, just because they all have the same MTBF
doesn't mean that they're all going to break at the same time.
Debbie
| |||||
| 147.2 | Dual homing of Host | BERN01::DEY | PhV or Big wind, long talk, no rain | Wed Oct 03 1990 15:23 | 4 |
Will we support dual homing in a configuration where a Host has 2 FDDI interfaces, connected to 2 Concentrators on the ring ? Cheers Walter. | |||||
| 147.3 | KONING::KONING | NI1D @FN42eq | Wed Oct 10 1990 17:32 | 6 | |
That's not the same sort of dual homing, that's simply two FDDI stations connected to the ring. It's no different from having two Ethernet adapters in a single node, and it will work in the same cases. (In particular, DECnet phase 5 fully supports it; other cases may be more limited.) paul | |||||