Building a TCP/ IP Network Over Dark Fiber?

1101z asks: "Well I work for a public access station in a city where a second cable/phone/internet company has moved just started operating. Part of there deal with the city was to let us have (for free) dark fiber links between several location in the city and our studio, so that we would be able to cablecast live from those locations. As the computer guy I would like to be able to interconnect computer networks that already exist at several of those locations, when we are not using the fiber for cablecast. The question is what is the cheapest way to build a TCP/IP network over this dark fiber." I wonder if the fiber being used is related to this story, from a month ago?

Comments

Re:Nothing to do with dark fiber

[nathanh]

"I don't know how to design a network, can someone do it for me?"

This should not have been moderated down as flamebait. The question was so open-ended as to defy imagination. This "flamebait" was simply the truth and sometimes the truth hurts.

Just to explain how damn useless the question is, there is no information about existing equipment, servers, desktops or applications. No explanation of the requirements for inter-site traffic (queuing only? interactive sessions? thin clients?). Does he want to use the fibre for data and voice? Does he want a single LAN or routing between sites? How many people per site? Is this a distributed or centralised server model? What's his budget?

He hasn't even explained what sort of fibre it is! Single mode? Multi mode? Frequency division? Can he afford a fibre ring? What sort of redundancy does he need? How long are the fibre runs?

There are plenty of solutions here - ATM between sites with LANE, GigE into some 3550s, 10baseF into tranceivers - but there's no way you can give him an answer without more information.

This guy obviously doesn't even know the extent to which he's in over his head. He should hire somebody with experience to do this job for him.

NICs not switches

[MrResistor]

Everyone seems to be focusing on puting fibre switches at each location, which I think is an unnecessary expense. The way I read the question you already have existing network at each location, and you just want to hook them together.

It seems to me that you could just get a few PCI fibre NICs and use them to set up existing machines at each location as bridges. I don't remember how much they cost, but it would definately be cheaper than switches. You'd have to make sure you had the right plugs/jacks, obviously.

It seems to me that it would be a pretty simple thing to do.

Re:NICs not switches

[Twirlip of the Mists]

Everyone seems to be focusing on puting fibre switches at each location, which I think is an unnecessary expense.

Yeah, but the thing is that each site is presumably going to need a switch anyway. It's much simpler to just link the Ethernet switches together to form a single network segment across all the links than to mess with routing and whatnot on dual-NIC PC's. Cheaper, too, since, like I said, they're going to need those switches anyway.

That said, dual-NIC PC's could work. You'd have to allocate a different subnet to each site, and set up each computer on the whole network with the correct routing tables, but it could be done. I just think switch-to-switch is simpler.

Re:NICs not switches

[Gerry Gleason]

I love to be the one to break this to you: network gear is just machines with NICs in it.

I hate to break it to you, but this is wrong. The simplest switches will be nothing but a backplane and special purpose hardware to connect each link up to the backplane. No processor necessary. More complex and flexible gear that can do a lot of complex routing an filtering will probably have a processor, but it only gets involved in configuration. Packets flow in and out without a processor every touching them.

PCs have lots of things that aren't even a little necessary for this, in particular disks that have a very high failure rate compared with chips and such. Further, the biggest problem is the OS that you have to boot and configure, and a purpose built device will just turn on and go. It is just much more likely to just work, whether you are talking about cheap simple NetGear stuff or more complex Cisco routers and switches.

Did you fail to notice the 'Ask Slashdot' aspect of this? This place is full of network consultants. Hell, anyone who has ever answered someone's networking questions for money outside of a salaried position is a network consultant.

So what, my point was that there are a lot hardware choices, and as others have pointed out, he didn't specify enough to know for sure. Rather than spend money on devices that don't quite work for the job, get a little help from someone who can say for sure what will and won't work. I've actually done networking work both for salary and as a consultant, but I don't consider myself a network consultant because I don't do it enough to be able to definitively say what will and won't work. Expirimenting can be expensive.

Re:Crazy hack: PPP over Digital Video...

[deicide]

I remember seeing a PCI card that allowed hooking up a regular VCR and using VHS tapes for backups. Several gigabytes per tape - mind you, this was when 1 gigabyte hard drives were common.

If you "watched" the tape it would appear as series of white/black squares on the screen.

Let it GO

[Oculus Habent]

Look,

Without the additional details that are "required" by some of the posters, you can only speculate at an answer. Twirlip Of The Mists has done that, and had some very reasonable suggestions.

However, for a complete and assuredly valid answer, we simple need for information. As he said "let us have (for free) dark fiber links" that may mean that he really has nothing but fiber between buildings. Telcos aren't known for their sweeping generosity. He may have a lambda, which is absolutely reasonable in a metro area, which would give him something to work with.

If the fiber has sufficient bandwidth, he could split the fiber into data and video traffic (my high school used an OC3 in this manner for ITV classes and Internet access), but this would likely cost a good deal more.

The issue I have with the whole thing is "...when we are not using the fiber for cablecast." If you want cheap, as Twirlip Of The Mists suggests, that will mean (I could be wrong) physical disconnection of network cabling at both ends each time you broadcast, and then re-connection after broadcast. Would you have trained network people at each "public access" location, or would you end up driving around town before shows? Is it worth it to you?

Granted public access television isn't rolling in money, but to make your life easier, you probably want something you don't have to physically connect each time. Of course, you could get a fiber switch, and some X10 appliance switches and the Home Connect kit. Then you could just call up and switch off the data and switch on the feed.

I want it to be clear that I am not saying that would work.