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Conference netcad::hub_mgnt

Title:DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:NETCAD::COLELLADT
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

72.0. "DECbridge90...possible throughput problem" by AKOCOA::NCOLLINS () Wed Nov 04 1992 09:21

I am in the process of installing DEChubs in AKO1. The building has been 
completely re-wired, with DECconnect to every office.

I've started by installing the DECrepeater90C, but I've started having problems.
One section of the building, all there workstation crash. At the same time that
this is happening, another section of the buildin loses all LAT connections.
Sometimes another section, which are using PC's, loses their window to there PC
server.

I spoke with a fellow Network Support person and told them of my problem. They 
suggested that the problem may lye with the DECbridge 90 not having the needed
throughput. I have since removed the bridges and I'm using a different configuration

My question is, what is the throughput of a DECbridge90, and how dose it compare
to the LAN Bridge 100 or 200?

I have inclueded my LAN configuration using the DEChub products. Maybe I'm
missing something. Any help would be greatly welcomed.

Thanks,

Norm



DEChub w/ DECrepeater90C & DECbridge90 using AUI port --->DELNI --->*

*---->ORNET fiber transceiver--->ORNET fiber transceiver--->DECbridge620 on a 
FDDI ring.

Both ORNET transceiver have SQE test, Alternate collision Mode, and Full step mode
disabled.


In an attempt to eleviate my problem, I have installed the following configuration.


DEChub w/ DECrepeater90C --->DEMPR --->ORNET fiber transceiver --->DECbridge620.
T.RTitleUserPersonal
Name		DateLines
72.1Try another DB90??CGOS01::DMARLOWEPDP 11: MOV -(PC),-(PC)Wed Nov 04 1992 10:1613
    The DB90 is listed as being able to forward 14,847 out of a possible
    14,880 pps.  Have you done a DISPLAY when connected to the DB90
    to see what the counters are saying?  Is there only one path to
    the affected nodes?  I have seen similar effects with running 2
    DB90's in parallel and then causing one bridge to fail.
    
    I have done DECNET loopbacks between serveral nodes each on different
    sides of a DB90.  Without the DB90, LTM showed very spiky in the
    area of 70-75%.  With the DB90, LTM showed a flat line at 69%. 
    I attribute this to the DB90 adding a layer of store and forward
    and more collision resolution in the link.
    
    dmm
72.2could the DELNI be the problem??AKOCOA::NCOLLINSWed Nov 04 1992 11:4011
Thank you for the reply. I did try serverl different bridges.

I was just reading the documentation for the DEChub 90 Ethernet Backplane and 
I noticed that nowhere do they show the use of a DELNI to connect multiple
work group hubs together. They show either the DECbridge connected directly to 
a H4005 or the backplane, without the bridge, connected to a DEMPR or DESPR then
to the H4005.

Is there a reason why they don't show a configuration using DELNI's?

Norm
72.3To DELNI or not to DELNI...CGOS01::DMARLOWEPDP 11: MOV -(PC),-(PC)Wed Nov 04 1992 12:4413
    I don't know why it shouldn't work on a DELNI.  Afterall I've seen
    LB150s on DELNIs.  I do have one customer that can't/won't connect
    their 3 VAX9000s to the same DELNI.  Something about loading the
    DELNIs and traffic starts going astray.  They have tried swapping
    the DELNIs, even with new units but still no luck.
    
    Now I'm not going to get into a long conversation about DELNIs and
    how fast they should or shouldn't work.

    The bottom line is that the DELNI should work but why not try it
    without the DELNEI and see.  You just never know.  8^)
    
    dmm
72.4Still experimenting...AKOCOA::NCOLLINSWed Nov 11 1992 16:0621
Will, I have had the following configuration for the past week,

DEChub w/ repeaters ----> DEMPR ----> FOT ---> FOT ---> DB620
 
and so far no problems. Now with this config, I lose the capibility to use HUBwatch.
So I am also trying the following setup,

DEChub w/ repeaters & DECbridge90 using the thinwire port w/T-connector --->
>-- DEMPR ---> FOT ---> FOT ---> DB620.

Once again I am able to manage the HUB through the bridge.

I still don't know why the DELNI configuration didn't work. After looking in
various notes, checking all the rules, their seems to be no logical reason why
it didn't work.


Oh well!


Norm
72.5Put LTM on the DELNI?MEMIT::FORRESTFri Nov 13 1992 08:516
	I'm hesitant to suggest that you mess with something that's working, 
	but if you're still curious about the DELNI, then you might try 
	putting an LTM on one of the other DELNI ports. If there's performance 
	or collision problems, you should be able to see it.

	jack