| Title: | DEChub/HUBwatch/PROBEwatch CONFERENCE |
| Notice: | Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7 |
| Moderator: | NETCAD::COLELLA DT |
| Created: | Wed Nov 13 1991 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 4455 |
| Total number of notes: | 16761 |
I have been configuring 3 DECbridge 900's in a single hub and am
curious how the hub manager does the connections. I originally
thought that a network manager would be responsible for the A
B connections and knowing the rules but guess what!
First config:
Front panel A B
DB900 DB900 DB900
Backplane B AB A
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FDDI 1 ==============[1]=============[1]=============[1]===========
Bridge 1 and 3 have only 1 FDDI port into the backplane. When the
legs are dragged down and released, the FDDI # LED flashes for a
short time (pre-forwarding) and then everything is stable. If the
A and B ports of bridges 1 and 3 respectively are not connected
to anything, the green LEDs are out. Works great. According to
HUBWATCH you have only used 1 channel. FDDI is point to point however.
Does this mean in reality that 2 channels (2 groups of 6 wires) have
been used (B-A,B-A)?
Would it look like the following:
Front panel A B
DB900 DB900 DB900
Backplane B A B A
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==============[1]===========[1]= | |
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=[1]===========[1]=====
The next config really confused me.
Front panel
DB900 DB900 DB900
Backplane AB AB AB
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FDDI 1 ==============[1]=============[1]=============[1]===========
Now both A and B ports are into the backplane and joined. This
time the green LEDs for both A and B ports on each DB 900 are on,
indicating valid connections. Go into the FDDI ring display and
each A port, on all 3 bridges, shows it's connected to a B port
and each B port shows it's connected to an A port. The display
doesn't show where the connections come from or go to so I don't
know how it's really been configured by the MAM.
Anyone redraw this so as to give a glimpse of how the MAM would
handle this config?
By the fact the the FDDI ports are port 1, you do not have a lot
of control as how AB connections are made. Some but not a lot.
Maybe it's for the better? 8^)
dave
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 1058.1 | LEVERS::ANIL | Thu Jun 02 1994 19:53 | 32 | ||
Although the FDDI is shown as a bus in the LAN interconnect window,
as you say it's actually a ring with point-to-point connections. By
obscuring the physical topology (at least in this window), HUBwatch
makes it easy to set it up as a LAN.
> HUBWATCH you have only used 1 channel. FDDI is point to point however.
> Does this mean in reality that 2 channels (2 groups of 6 wires) have
> been used (B-A,B-A)?
If you consider setting up the equivalent with wires, note that even
receive and transmit are separate for each connection. This takes up
4 channels as far as I can remember.
> The next config really confused me.
>Go into the FDDI ring display and
> each A port, on all 3 bridges, shows it's connected to a B port
> and each B port shows it's connected to an A port.
Again consider the same with wires. You would need a wire
from A(1) to B(2), A(2) to B(3), and A(3) to B(1). This should
take up 6 backplane channels in all, allowing for rx/tx.
> By the fact the the FDDI ports are port 1, you do not have a lot
> of control as how AB connections are made. Some but not a lot.
> Maybe it's for the better? 8^)
Why does FDDI being bridge port 1 affect how much control you have
over A and B? Note the difference between the PHY ports and bridge
ports. It certainly is for the better.. as you can imagine
it would be a lot harder to set up FDDI without the LAN abstraction.
Anil
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| 1058.2 | Just what is the MAM doing? | CGOS01::DMARLOWE | Have you been HUBbed lately? | Fri Jun 03 1994 02:29 | 34 |
> If you consider setting up the equivalent with wires, note that even
> receive and transmit are separate for each connection. This takes up
> 4 channels as far as I can remember.
What you're saying is that an A to B port connection will use 2
channels or 12 wires. Bye, bye 14 channels real fast if doing DAS
and lots of FDDI modules, etc.
> Again consider the same with wires. You would need a wire
> from A(1) to B(2), A(2) to B(3), and A(3) to B(1). This should
> take up 6 backplane channels in all, allowing for rx/tx.
Which is supported now, tree or DAS in the hub? I thought it was
tree. If it's a tree then wouldn't the A(3) to B(1) connection
not be made as that would be a DAS dual ring? And with that shouldn't
one green LED be out on the front to indicate no connection? As
it was both A and B port LEDs were green for all FDDI ports.
> Why does FDDI being bridge port 1 affect how much control you have
> over A and B? Note the difference between the PHY ports and bridge
> ports. It certainly is for the better.. as you can imagine
> it would be a lot harder to set up FDDI without the LAN abstraction.
I kinda like the way it's done. Removes the guess work out of
configuring FDDI's. It's just that I had bridge #1 with it's A
port into the hub and B to the front. The #1 port for this bridge
was connected to a FDDI LAN. I tried to reconfigure both A and
B into the hub without first removing #1 from the FDDI LAN and I
got a SNMP SET FAILED error message.
It's probably just a case of being really sure of your LAN topology
before you click. Especially with FDDI.
dave
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| 1058.3 | KAOFS::S_HYNDMAN | Acronym Decoder Ring Architect | Fri Jun 03 1994 10:49 | 6 | |
There is some good config information in note 651
Scott
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