How many hubs is too many?

[BobWeaver]

I have a client with a network problem. I suspect too many hubs. Someone once told me that there should be no more than 2 hubs between any two LAN nodes that want to communicate with each other. However, that is not physically practical in this situation. Between the computer C1 and the printer P1 there are a total of 3 hubs, one switch and one Ethernet to Localtalk converter and a couple of media converters. The topology is as follows:

C1------H1====H2-------H3====MC1-------S1-------MC2====EL1..........P1

Where:

Cn Computer (Macintosh)

Pn : Printer (postscript laserwriter)

Hn : Hub

Sn : Switch

ELn : Ethernet to LocalTalk adapter

MCn : Media converter (coax to 10/100baseT)

------- : 10/100BaseT cable

==== : Coax cable

......... : Localtalk cable

Switch S1 also has the Filemaker Server computer connected to it, and is connected to two other large hubs which serve about 80 computers. When the C1 Filemaker client tries to print to P1 during busy times of the day, The mouse cursor changes to the little wavy network thingie, and the computer locks up. Occasionally, lockup also occurs during other filemaker operations, but most often during printing.

Does anyone have a good rule of thumb about how many hubs are too many etc.?

[LiveOak]

I've always heard that via 100basedT a path should be limited to 2 hubs/switches. If you have a lot of network ports:

1) Use large hub/switches

2) Interconnect the first level hubs/switches using the manufactures proprietary bussing or a gigbit backbone.

We really don't know if your problem is due to load, in which case reorganizing architecture or adding switches in place of hubs may help. Or delays/packet errors, in which case 2) is applicable. The obvious long pole in the tent is C1, the series H1, H2 connection really needs to disappear and C1 connect directly to H3 or a new H4 connected to S1.

-bd

[Anatoli]

IMHO use first Switch to separate different departments and then maybe another Hub or Switch for local wiring. That should work.

[BobWeaver]

This is a multi-building site with the buildings connected via coax, and the nodes within each building on 10/100BaseT. We just found a few more cables running between buildings, so it looks like we can arrange things a bit better. We'll give it a try anyway. Thanks for the advice.