Conference netcad::hub_mgnt

1816.0. "Config Questions?" by ANGLIN::CLAYTON (Merlin Clayton DTN 445-7217) Thu Dec 22 1994 14:12

We have a customer who has a bunch of legacy DELNIs and DEMPRs installed 
on the floors of his building and the data center.  He wants to phase 
them out and replace them with DEChub products, but does not have the 
budget to do the whole building right now.  

In the first phase, he wants to wire the building with a fiber backbone 
and replace the DELNIs in the computer room with a DEChub 900 and fiber 
repeater modules for connecting all of the computers (20), and the 
various workgroups in the building.  However, he wants theh workgroups 
to continue to be connected to DELNIs and DEMPRs.  The DELNIs would be 
connected to the fiber backbone via and AUI-to-Fiber transceiver, and 
the respective DEMPRs and terminal servers would continue to be 
connected to the DELNIs.  There would also be some workgroup 
segmentation in the master hub in the computer room via the per-port 
switching capabilities of the 900 FP repeater.

A typical floor configuration would look something like the following:

						  DEChub 900
						______________
	DEMPR---|D|				|9| | |	   |9|
		|E|				|0|9| |	   |0|
	DEMPR---|L|---|FO/AUI|==================|0|0|9|	   |0|
		|N|		Fiber (MMF)	|F|0|0|	   |E|
	DEMPR---|I|				|P|F|0|	   |F|
						| |P|F|	   | |
						| | |P|	   | |
						--------------

There are multiple DELNI/DEMPR combinations per floor.

There are 13 DELNIs and 20 computers which would be connected via the 
900 FP repeater.  

Q. Are there any gotchas in this configuration trying to conenct the 
DELNIs to the 900 FP repeater?

Q. What would be the most cost effective way to replace the DELNI/DEMPR 
combinations on each floor (there are from 100-160 users per floor)?
(I'm thinking the high density thinwire repeater in a 900 backplane with 
 a 900FP repeater per floor for workgroup segmentation.  But the high 
 density port switching thinwire repeater is out a ways yet.)

Any alternative suggestions for a better configuration to meet the
customer needs would also be appreciated.


Thanks.

Merlin

    
    Just watch your total repeater hops.
    
    We use TP/AUI MAUs here to connect old DEMPRs through DELNIs to DETMMs;
    it works fine (we have to wait for those new repeaters too :-)
    
    > (I'm thinking the high density thinwire repeater in a 900 backplane
    > with a 900FP repeater per floor for workgroup segmentation.  But the
    > high density port switching thinwire repeater is out a ways yet.)
     
    Hmm... bear in mind - a repeater does not segment.  If you connect
    users to to repeaters which then go across backplane channels to a
    DECrepeater900FP, and then repeat all the ports together within  the FP
    (the default configuration), then you have just 1 segment.
    
    If you want to create multiple workgroup segments, then you want a
    switch - not a repeater.
    

RE: -1


>>    Hmm... bear in mind - a repeater does not segment.  If you connect
>>    users to to repeaters which then go across backplane channels to a
>>    DECrepeater900FP, and then repeat all the ports together within  the FP
>>    (the default configuration), then you have just 1 segment.
    
>>    If you want to create multiple workgroup segments, then you want a
>>    switch - not a repeater.


Right.   I was planning on configuring ports/groups-of-ports to specific 
backplane IMBs (not exceeding the limitation of 6), and switching the 
various IMB segments via the 900EF switch that I included in the diagram
in .0.  I think we're talking the same thing.

Mgc