Conference netcad::hub_mgnt

1750.0. "FDDI & Ethernet config questions" by OTOOA::OTP149::typhair (32 bits : Road-Kill on the Information Highway) Fri Dec 02 1994 09:57

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Note: 1511.0                scenario....need input-thanks!          1 reply
OTOU01::TYPHAIR                                     35 lines  29-NOV-1994 22:45
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Question

I need to implement the following

VAX             VAX             VAX
|               |               |
DEChub90        DEChub90        DEChub90  -each 90 consists of repeater &
|               |               |               bridges
|               |               |
\               |              /
 \              |             /
  \             |            /
   \            |           /
   DEChub 900 (10/100 Bridge)
        (DECconcentrator)
         /      |       \
        /       |        \  FDDI connections
       /        |         \
     VAX      Alpha      VAX

The above configuration is larger than is shown, but reflects the design.
There is a DECnis router to connect remote sites back to the local systems, it
will also be connected to the FDDI.  The systems are standalone along with a
couple of DSSI clusters.  The customer would also like to implement a failover
Ethernet capability using the existing Ethernet controllers on their systems.

The main applications are Pathworks and custom host applications(terminal
access).  Protocols are LAT, DECnet, Netbios, LAST.  In addition, the customer
wants to utilize the FDDI for backups.

I've been reviewing the conferences in search of information surrounding the
above, some success to-date...

I'm looking for comments specific to gotchas in implementing the above
(counters, settings, issues, etc).

Just as an update, the suggestion was made to cross reference this in the 
this conference.  It was posted in the FDDI conference with no input to-date.

Input...

Cheers
Steve

    Can you be more specific about the configurations; especially the
    DEChub 90.  You said 'each 90 consists of repeater & bridges'; you can
    have only one bridge in each DEChub 90
    

I should also add to .1 the following:

1) The production systems are VAX based and running VMS V5.5-2
2) They are running PhaseIV on the VAX systems
3) The AlphaServers are running version 6.x and PhaseV

As we understand it our buffer sizes for the nodes on the ring will need to 
be 1498 and not the 4.5k under FDDI.  This is due to the need to go to 
Ethernet from the FDDI and also to the DECnis router which is working with 
576 buffer sizes.  Does anyone have the rules for what is legal specific to 
the above and the necessary buffer sizes.  Right now as we can see it we 
would need to set the VAX systems up with a line buffer size of 1498 for the 
FDDI link and an Exec buffer size of 576?  The Alpha systems we believe need 
to be the same or because their running PhaseV can we leave them at a line 
buffer size of 4.5k for the nodes on the Ring?

The second point is how might we implement a failover Ethernet without 
causing confusion on in the network.  The intent is to connect the nodes off 
the ring to an Ethernet LAN which connects into either a DEChub 90 or 900 
bridge port.  The intent is to put the circuit cost high for the Ethernet, or 
is it a case where we can keep it plugged in but shut off.  Then if it fails 
we need to manually/program a start up of that circuit?

Thanks in Advance
Steve