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Inter building networking

Superuser
Superuser
Posts: 2,763
Thanks: 470
Fixes: 5
Registered: 06-04-2007

Inter building networking

Hi
Some may remember a while ago I was asking for advise on a wireless connection between our Church and Church Hall.  I've been doing a little bit of work on this and a lot of discussion!  One other area I would like to explore before a final proposal is put together.  This is a wired link between the building.  Installation would probably be much cheaper (or virtually nothing) since I have people who could dig a trench between buildings for the cost of a few cups of tea and bacon butties!
I'd estimate the buildings are approximately 130m apart on the route the connection would need to take, so lets say 150m by the time it makes it to the equipment at each end after going on a little diversion or anything else I've not thought of yet.  That distance will be too far for Cat5 to be within specs, so it would need to be fibre.
Can anyone advise on a supplier for the actual fibre and media converters?  Also What type of termiators are best to use?
Many thanks
Phil
33 REPLIES
Lurker
Grafter
Posts: 1,867
Registered: 23-10-2008

Re: Inter building networking

I use Black Box for my networking gear, and they do supply fibre to any length you specify, with options to have them ready-terminated in whichever format you want.
Multi-mode cable will be fine for that type of distance, and is cheaper than single mode (as are converters etc)
I tend to run fibre straight into a fibre patch panel, presenting as a pair of female ST connectors. As I use a lot of Dell switches, I use their SFP Gigabit LC modules, and then simply use a patch lead made up with male ST connectors on one end, and a male LC connector on the other end.
Presumably you won't be adding large numbers of nodes on each end, nor will you be needing high capacity managed switches, so I'd look at standalone media converters.
I intend to use some of the Black Box DIN rail mounting converters from their industrial range for a couple of projects later this year - of course you then need a power supply too as well as a DIN rail to mount to.
I have a couple of prosumer type desktop devices knocking around my office ATM that I use sometimes for testing etc - they are from Allied Telesyn International.
They are 10/100 ST>RJ45 converters and work absolutely fine. Don't know exactly where they came from, as I got them as part of a bunch of stuff at a liquidation sale.
A big advantage of the Black Box fibre is the option to have the cable terminated in a proprietary end-cap, which once installed can then have the fanout added (The fanout is the most fragile part of the installation, since they are the glass fibres without the strain relief insulation seperated out to fan to the inside of the ports on the fibre patch panel.)

As an example, a 150m 12fibre length would be £1100, and a pair of 1m fanouts (MPO to ST) would be £422, with a pair of patch panels to terminate the fibres in would be £99.90
Assuming you already have a couple of 19" racks to support the patch panels in, you only need to add the cost of the media converters, or network switches and you are done.

You could get a Laserlink if you have line-of-sight between two windows. They are about £2500 for the kit, and you simply point them at each other out of windows and they maintain a 100MB link using Laser beams. (Remember to install high enoug up that pedestrians don't interfere with the beam - also expect deterioration during periods of snow.
Denzil
Grafter
Posts: 1,733
Registered: 31-07-2007

Re: Inter building networking

Is there a mains link between the two buildings? Something like <a href="http://www.maplin.co.uk/module.aspx?TabID=1&criteria=usb&ModuleNo=223818&doy=search&C=SO&U=Strat15">this</a> might be an easier alternative.
Community Veteran
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Registered: 13-04-2007

Re: Inter building networking

At the sort of length you are using you should get away with Cat5 the actual specs are
Here are the 'offical' specs:
(100Base-t IEEE 802.3u)
100Base-T4 Category3 or 4 = 100Metres (4 pair)
100Base-TX Category5 = 100Metres (2 pair)
100Base-FX Multimode fibre = 2Km , single mode 10Km
(100VG IEEE 802.12)
Category 3 , 4 or 5 (4 pair) = 100Metres
Multimode fibre = 2Km
These actual specs are not set in stone and I have heard of 500 mt working
But if you are burring it  and its away from noise it should work fine and very cheap compared to the alternatives. You could test it over ground before you trench it to be sure but i have done those sort of distances underground in a pipe. Run 2 cables for safety
Superuser
Superuser
Posts: 2,763
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Registered: 06-04-2007

Re: Inter building networking

Thanks guys.  No they aren't on the same mains link.  The problem with running cat5 (or cat6) over too long a distance is the collision detection rates.  I might have a play with it though.
Phil
Community Veteran
Posts: 4,729
Registered: 04-04-2007

Re: Inter building networking

Would it be possible to locate a switch half way between to the two building (or at least within 100 metres of each) ? This would get over the 100 metre limitation.
Mains electricity does not need to be available at the intermediate point, as you could use a cheap domestic style switch that has an external power supply, and run a low voltage cable alongside one the the ethernet cables. (Use at least 1.0mm2 cable to prevent voltage drop.)
Superuser
Superuser
Posts: 2,763
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Registered: 06-04-2007

Re: Inter building networking

Not really chilly.  All that is between the 2 buildings is a grave yard and a field.  Not even a shed in sight!  I could put a man hole half way, but I suspect the switch wouldn't like the middle of winter!
Phil
Community Veteran
Posts: 4,729
Registered: 04-04-2007

Re: Inter building networking

No a man hole is not a great idea. Back to the wireless, unless there is a  cheaper priced fibre option.
Community Veteran
Posts: 4,729
Registered: 04-04-2007

Re: Inter building networking

How about High-Speed Ethernet Over Video Cable
I have no knowledge or experience of these products, but from the description it looks like it can provide an ethernet connection over upto 300 metres on co-axial cable.
Another option;
http://www.amplicon.co.uk/data-comms/info/ethernet-extender.cfm
Community Veteran
Posts: 3,789
Registered: 08-06-2007

Re: Inter building networking

Fibre really is the way to go.
I suspect you could get away with doing it for around a grand. 
I would recommend something along the lines of:
2 x Netgear GS724T Smart Switches    ~ £205 each
2 x Netgear AGM721F Fibre SFC (for fibre installations of up to 500m, using multimode fibre) ~ £140 each
1 x 200m 4-core multimode fibre pre-terminated with SX connectors,  around £256 from netshop (netshop.co.uk)  (giving a spare set of cores)
Total, ex vat, of around £946
B
Community Veteran
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Registered: 01-08-2007

Re: Inter building networking

Quote from: samuria
At the sort of length you are using you should get away with Cat5 the actual specs are
Here are the 'offical' specs:
(100Base-t IEEE 802.3u)
100Base-T4 Category3 or 4 = 100Metres (4 pair)
100Base-TX Category5 = 100Metres (2 pair)

I'd never recommend running a cable that length underground actually. Lightening storms can still affect network cables when underground and have been known to knock out the networked devices on both end of the cable. That is a very bad idea. Either wireless which is due to its nature inherently insecure or fibre optic. That is the only way in this situation.
Cat5 might work well in the garden shed scenario (where you could still use wireless) but never over 130m near a building like a church - which will almost certainly have a tall tower and thus attract lightning...
I need a new signature... i'm bored of the old one!
Superuser
Superuser
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Registered: 10-04-2007

Re: Inter building networking

Another option for the driver component Phil.  http://www.blackbox.co.uk/products/display.asp?id=0&doc=lgc320a&tx=9&sx=1
Found whilst browsing the Black Box catalogue for something else Smiley    No pricing given though.
Maurice
Superuser
Superuser
Posts: 2,763
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Registered: 06-04-2007

Re: Inter building networking

Thanks Maurice.  I'll give them a call.
Phil
Lurker
Grafter
Posts: 1,867
Registered: 23-10-2008

Re: Inter building networking

I think they were around £400 each last time I looked for the multimode ones. Worth giving them a call though, as they are eternally parient and helpful at Blackbox
VileReynard
Seasoned Pro
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Registered: 01-09-2007

Re: Inter building networking

Have you considered the extra switch / repeater option, but building a small greenhouse etc at the half-way point?
It would keep the switch above water, and allow you to grow a few vegetables.  Crazy Crazy Crazy