topic Re: Networking in Operating System - OpenVMS

Networking

Doreen Mainza — Tue, 25 Nov 2003 04:23:03 GMT

Is it safe to network computers in 2 different buildings with an ethernet cable by connecting it like a telephone line (not using fibre but passing it from 1 building to the other through the roof)? Our area is prone to lightening during the rainy season.

Re: Networking

Lokesh_2 — Tue, 25 Nov 2003 04:37:11 GMT

Hi,

I guess the best answer in this case will be given my an electrician!
Why over the roof? why not through ground, it will be safe and will less wear-and-tear your cable .

Best regards,
Lokesh

Re: Networking

Ian Miller. — Tue, 25 Nov 2003 05:25:33 GMT

I guess shielded cable would be the thing but consult local electric person. I belive there are suitable cables made but sometimes the lightening is just too much for anything :-(

Re: Networking

Duncan Morris — Tue, 25 Nov 2003 05:27:14 GMT

Doreen,

we tried this in Zimbabwe many years ago, but had problems with differences in the earth potential in each building. Although it might work in the short term it is unreliable and we opted to put in a fibre bridge between the buildings. Lightning of the sort you get in Southern Africa definitely causes problems with ethernet between buildings!

Re: Networking

Willem Grooters — Tue, 25 Nov 2003 06:21:35 GMT

One other problem you will encounter: The maximum distance for Ethernet is limited, you you'll need extra hardware anyway (and each requires power as well).
As for lightning: direct hit is something you can just wait for. It will happen, and I don't think your insurance (or is it: assurence, I always forget ;-)) will hold on that. Shielded cable or not - your systems will be damaged severely. Shielding will limit other interference (note: LIMIT, not PREVENT) that could otherwise comprimse the connection.
I think the cost of prevention of damage and dataloss, and the cost of insurance weighs the cost of fiber connection.

Re: Networking

Dieter Rossbach — Tue, 25 Nov 2003 07:16:52 GMT

What about using wireless lan?
We connect two building across a street with two WLAN-Bridges, it is fast, save, simple to install and cheap.
Disadvantages:
Decnet only via Decnet/Osi over IP
No Lat

Regards

Dieter

Re: Networking

Antoniov. — Tue, 25 Nov 2003 08:31:14 GMT

My customer has tryed with an optical line but with problem sometimes and now using RF (wireless network). It work fine; he have two network connected by wireless bridge; no LAT but telnet works very fine; pathwork is old but works; he doesn't use decnet.
I think RF is best solution.
Antoniov

Re: Networking

Willem Grooters — Tue, 25 Nov 2003 09:42:09 GMT

Dieter/Antonio:
Didn't think of it. RF goed be ok but what about:
* Radio interference
* Security (not only unauthorized access. Think of leakage of data as well)
* Bandwidth / Speed
* Legal limitations (forced by government rules)
* (there could be more ....)

Anyway: to be taken in account!

Willem

Re: Networking

Dieter Rossbach — Tue, 25 Nov 2003 11:30:13 GMT

Yes, there is a chance for security problems, but you can minimize them with a proper setup and the right equipment.
Restrict access to the mac addresses of the bridges, and choose a good antenna with reduced stray.