| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 143.1 | Response from the trenches | KALI::GAUDET | | Thu Feb 04 1993 17:44 | 7 |
| The DECagent 90 does not currently support more than one bridge in a
hub (extended hub included), nor is it likely to soon (certainly not in
V1.1, and I'm not optimistic about V1.2). Support for multiple bridges
would require major changes to the DECagent firmware, which is unlikely
to occur in the near future.
...Roger...
|
| 143.2 | | HANNAH::BUGSBY::COBB | Writing from ALPHA AXP | Fri Feb 05 1993 06:54 | 4 |
| Does this mean that we cannot connect 2 hubs together that have a
bridge in each of them??
Bill
|
| 143.3 | That's exactly what it means | KALI::GAUDET | | Fri Feb 05 1993 09:49 | 8 |
| All I can say is that it's not supported. When the DECagent is using
the work-group bridge to determine the hub configuration, an
architectural restriction within the bridge prevents the DECagent from
identifying the location and MAC address(es) of the other bridge(s).
This restriction is fundamental to the bridge and therefore causes the
same problems in the DEChub 900.
...Roger...
|
| 143.4 | one strange example | CGOS01::DMARLOWE | dsk dsk dsk (tsk tsk tsk) | Sat Feb 06 1993 00:38 | 26 |
| But isn't there some restrictions within the DECagent also? When
the agent has one known bridge and you try to manually add a bridge
thru "ADD MODULE" it gives you an error message. Also how many
of the bridge restrictions you mentioned are related to which bridge
is master of the serial management?
I have found that with dual bridges (slots 7 & 8) and a DECagent 90 (slot
15) in an extended hub, that many strange things happen. The agent was
set for the bridge in slot 8 (bridge B). Bridge B was the lowest
Ethernet address so it was active. Load the extended hub up with
DECNET mirror packets, maybe up to 70% Ethernet utilization and
after less than a minute the CRT (OBM port) showed the bridge in
slot 8 was replaced with a box and the word UNKNOWN in it. After
a few more seconds the box in slot 8 disappeared and an inverse
video bridge showed up in slot 7 (bridge A). The inverse video
never did clear which meant that the agent saw the bridge but could
not communicate with it. Even removing the active bridge in slot
8 so that the other bridge became active and eventually serial master
did not clear the inverse video on the CRT.
I don't know if this expected behaviour but I thought I'd mention
it. Redundant bridges in hubs are important to customers to maintain
high availability.
dave
|
| 143.5 | This is as clear as I can put it | KALI::GAUDET | | Mon Feb 08 1993 16:48 | 17 |
| Let's lay the cards on the table right here...
***** DO NOT PUT MORE THAN ONE BRIDGE IN THE SAME HUB *****
Extended (daisy-chained, 16-slot, call-it-what-you-want) hubs included.
The architecture of the agent code can't handle it and it's not going
handle it anytime soon.
Understand, I think that having multiple bridges in a hub is a good
idea, but the code just can't deal with it at the moment, and we're
just too darn busy with developing functionality we've already
committed to for V1.1 (and V1.2).
Sorry folks, but it's one bridge per hub. Period.
...Roger...
|
| 143.6 | You can put a standby bridge standalone off the backplane port | MEMIT::FORREST | | Thu Feb 18 1993 10:46 | 19 |
|
For now, if the customer has a single hub, and wants a standby
bridge, you can provide a standalone DECbridge 90 off the ThinWire
port of the backplane. It will not take over repeater management,
but it will take over bridging the hub to a backbone.
You can manage the standby bridge with the same agent by adding
another community, consisting of the standalone bridge.
I will investigate whether putting a T connector on the ThinWire
connecting 2 physically adjacent backplanes could also be supported.
This would allow a standalone standby bridge for the 16 slot
configuration. But don't go selling this solution until I reply
back here that it can be supported.
We also have to understand when we can support multiple bridges in
a hub in the DECagent 90.
jack
|
| 143.7 | Official and unofficial | CGOS01::DMARLOWE | dsk dsk dsk (tsk tsk tsk) | Thu Feb 18 1993 11:27 | 8 |
| Officially the backplane is 15 stations so daisy chained would give
you 30 stations. But you still are allowed 55M of thinwire between
the 2 hubs. So even though its not "officially" supported I don't
see a problem putting a DB90 on the coax between 2 hubs. That is,
as long as the 2 hubs are side by each in the wiring closet. I
wouldn't do this if you had 55M of coax between the hubs.
dave
|