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Hardware Networking FAQs?

Posted by Cliff on from the cabling-101 dept.

TufelKinder asks: "Our company is installing a new network at a new building location. There don't seem to be many discussions that center on the best cabling systems, etc, to use. I'm wondering what /. folk have found to be the best brands/types of copper cables to use for 10/100BT networking and for gigabit over copper as well. Are there any specific types of cable or cabling practices to avoid?"

25 comments

  1. Some advice... by cmowire · · Score: 5, Informative

    I am not a network expert, so take this with a grain of salt.

    Get the best cable you can get at a reasonable price installed everywhere. Don't get the super-duper-will-be-good-for-1000-gigabits sort of cable. But do wire the desktops with a decent Cat-5e that will let you run gigabit when the price comes down for it so you don't have to do it again. And you know that, at some point, many users will start to need gigabit performance on their desktop. It's inevatable.

    Make sure that you follow fire safety code. Only certain types of cable can be run through the walls.

    Cable management is a very important consideration. The best system is one that lets you add more wiring whenever you want, keeps the cables neat, etc. I know part of it is making sure that you have ample conduit space through the walls, so you can run more cables later on. I know that another part of it is having those faceplates that let you add more jacks.

    Do try to wire every room, even if it seems stupid. You never know what will happen later on.

    Don't run everything through the same conduit set. Running power cables next to network cables is dangerous, stupid, and not good for network reliability. I think that's also against most building code.

    You might want to wire the phone cables with Cat-5 or better, stupid as it seems. IP telephony is taking off and those might end up being used to wire up netphones.

    Get a raised floor where all of the servers and hubs will be.

    Try to have things set up so that you have no long cable runs. This may mean several networking/telephone closets. I'm not sure what the good maximum length is, so somebody else will have to fill that in.

    Keep a map of what is cabled where. And keep it up-to-date.

    --
    Gentoo Sucks
    1. Re:Some advice... by sharkey · · Score: 4, Informative

      Phone cable: The price between CAT-3 and CAT-V is very minor, and it does give you room to grow.

      Gigabit "ready": Compare prices between CAT-V and CAT-6. Clean underpants, then run CAT-V. GB to the desks is probably overkill, but if you really need it, it's gonna cost you, whether using copper or fibre.

      Raised floor: If there are other tenants below, running the entire network through the floor/drop ceiling below gets to be a pain. It is nice in the equipment room for in-room connects, for keeping the floors uncluttered.

      Length: 10/100bTX is spec'd at 100 meters max.

      Running with power can be done, but you need to use shielded cable (Price goes up).

      Fire code: Here in INDY, you can run PVC or Plenum through the walls, but you can get written up for running PVC through the building plenums.

      We are moving in December of this year. We get one floor in a multi-story salt-mine. We are running cable-trays through the drop ceiling, above all "aisles" in the cube farm, with wire-mold running down the structural supports to each cube "island". It is mostly an open-plan slave-pit, with filing, electronics, and kitchen in the center, and private offices at each end. We will not have to run thick bundles of cable over/through walls, or climb over cube walls, either.

      Private offices will have 2 net drops (not necessarily 2 ports on a switch), the conference rooms will have multiple drops based on size, to accomodate furniture movement in the future.

      Cable management and mapping is like commenting your code. Do it clean and keep it documented! I had to pull out a bunch of old 2-pair cable from our RS/6000 when it left. The bastards who ran it made it very pretty in the ceiling and floor by cable tying it every 3 feet in bundles, then to whatever was handy: ceiling supports, ceiling tile hangers, light fixture, power conduit, etc. Pain in the ass to pull out.

      --

      --
      "Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next.
    2. Re:Some advice... by cmowire · · Score: 2

      I checked the price and it seems like the cost difference between Cat-5 and Cat-5e is pretty minimal, and Cat-5e will be able to work with gigabit just fine over a reasonable range.

      Or was I forgetting something?

      --
      Gentoo Sucks
    3. Re:Some advice... by SuiteSisterMary · · Score: 2

      As a follow on, label the patchboards in the wiring closet, label the drops in the rooms, and get a floorplan, and put the patch numbers on the floorplan.

      --
      Vintage computer games and RPG books available. Email me if you're interested.
    4. Re:Some advice... by sharkey · · Score: 2

      Pricing that I've seen lately for patch cables, pre-cut & terminated (stranded PVC UTP) puts CAT-5e at just under twice the price of CAT-5, and CAT-6 at just over twice the price of CAT-5.

      I've just been looking, and none of the lists I have sell plain ol' CAT-5, so I have to say that I was referring to CAT-5e in my post. The price difference there between CAT-5e and CAT-6 is more than 50%. CAT-5e is GB rated, as you say, over reasonable ranges. I would use shielded cable for it, if I was to do it, and keep it well under 50 meters.

      Copper is a heck of a lot easier to work with than fibre, that's for sure, and even CAT-6 is cheaper.

      --

      --
      "Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next.
    5. Re:Some advice... by grimarr · · Score: 1
      The company I work for did this in 1998, and it's worked out really well. We were building the building from the ground up, and I was hired in time to get involved in the design, and even though it was my first significant network, it's worked out really well.

      I was able to get the computer room located near the middle of the building, so that the 100 meter limits were OK. We had suspended ceilings, with LOTS of air ducts up above (we're a chemistry lab company = huge ventilation needs), and there
      was plenty of room for cables. Make sure your installer runs the cables down the hallways, not cutting across rooms, and stays away from power cables. We ran plenum-rated cable everywhere, even the areas that weren't plenum, because it was so much easier.

      I put 4 drops of CAT5 at each persons desk, with 6 in a few offices, and 8 in the conference rooms. Several of the 4-drop offices are already
      maxed out, and you might want to make it 6 for at least the more senior people. On the other hand, the less senior people sometimes get crammed 2 to a room, and therefore 4 drops is hardly enough.
      There were several rooms that "didn't need many wires", because of their intended use, but now that the use has changed (took about 18 months), we're pretty short there. Don't shortchange rooms like that.

      I use CAT5 for both phones and data, and all the lines terminate on a big RJ45 patch panel. Then I use modular patch cords to connect outlets to the network switchs, or to the phone system, etc. I use blue cords for ethernet, green for digital phones, and red for analog phones (fax machines, etc). I used AMP panels and outlets, which have a small plastic colored "icon" that matches my color scheme, to make it less likely that someone plugs a modem into a digital phone jack (thereby frying it). Other brands have similar things.

      Do keep good records. Figuring it out later sucks.

      I use a cable tray running above the computer racks to get the cables to the servers. Much cheaper than a raised floor, and not TOO ugly.
      My biggest mistake was that the wiring closet is too small. The phone company told me that they would need 4 feet of wall space, so that's what I planned for. However, we get our phone and network service over fiber, and that meant they had to install a full-sized 7 foot rack, with batteries, etc. Then they used the wall space for the copper phone lines. (They pulled 300 pairs!! even though we only ordered 2 pair for the fire alarm. That's planning for the future!)

      Good luck!

  2. cat5 for short runs, fiber for the long haul by biot · · Score: 5, Informative

    Make sure you plan some space on every floor for a wiring closet while you still can; more than one for larger floors. Place them so you don't have to do more than about 50m from the closet to workstations. Use cat5 cable from the closets to where people will work. If any consultant or network type tells you to use cat6, fire him.

    Plan for at least four patches per desk; people will bring in laptops, or put double the number of people in an office. Don't forget the absolute minimum is two patches per person (computer, phone), and the minimum will last you about a month before people start bringing in little hubs to put on their desk (which you want to avoid).

    Between the wiring closets, use fiber. It's not as expensive as you may think, and terminating is quite painless -- many switches have fiber ports or room for fiber modules. You can also use fibercopper transceivers, not too expensive. Use single mode (SM) fiber. You need to do this because a) it can go much longer distances, b) you can happily string it alongside power lines if you need to, and c) because you can upgrade uplinks to gigE without worrying about the cabling.

    You'll also need to get copper into the wiring closets though, for connecting the PBX to the phones. Distance isn't such a big problem for those.

    If at all possible, get double the number of fiber links that you strictly need. Ideally, string it on different sides of the building or floor. You can't crimp it like you can cat5, and getting fiber types in for a splice takes a while. In a pinch, when one gets cut, it's good to have a guaranteed extra link ready, which is undamaged through following a completely different route.

    In the wiring closets, put switches, not hubs. Don't use hubs at all, in fact.

    Don't forget that the big cost in laying wire (both cat5 and fiber) is in man-hours, not the terminating equipment or physical cable. Putting in 10 cables isn't that much more expensive than putting in 1, in other words.

    1. Re:cat5 for short runs, fiber for the long haul by rdndc · · Score: 3, Interesting
      I agree wholeheartedly with your advice. Well, except for one minor quibble {grin}

      The costs for Cisco laser GBICs to drive SingleMode fiber are substantially higher than that of LED GBICs to drive MultiMode fiber. It seems reasonable to expect that SingleMode gear from other vendors would be similarly expensive. I don't know how much more expensive the SM fiber itself might be.

      So... my suggestion would be to use MultiMode where you can, as it will indeed carry Gigabit Ethernet, and only spend the extra money for SingleMode fiber where distances require.

  3. Cabling by _typo · · Score: 2, Interesting
    Put Cat5 everywere, it's cheap, but run it inside ample conduits were you can later on put fiber. When Gigabit really comes you'll probably want to do it over fiber. Run every line to a central location where you have the switches and asorted networking equipment and have a diferent swith for your servers. In that switch you can invest in fiber and gigabit so that your servers have ample bandwidth and are isolated from other computers, think sniffing.

    There is however one problem when using this setup that is when the server is trying to send more information than the client can take (1000Mbit server to 100Mbit client). This will cause errors and the network misperforming.

    Linux handles this with ECN (Explicit Congestion Notification), but some internet hosts deal badly with this.

    Anyway, to make a long story short, run todays regular solution everywere, think about upgraded connections for servers, and make sure upgrading is just a matter of buying new cable to run through existing conduits and new switches.

    --

    Pedro Côrte-Real.

    1. Re:Cabling by toast0 · · Score: 2, Informative

      having the server on a gigabit and clients on 100 meg won't cause errors... tcp/ip was designed with the thought in mind that not all network connections are created equal.

      (simplisticly) the client will only ack as fast as it recieves data, and the server will only send data a certain amount over what has been acked, so the server won't saturate its network connection if its saturating the client's

      --
      Need a Catering Connection
    2. Re:Cabling by A_Roche · · Score: 1

      There aren't any problems having your server on Gbit and your workstations on Mbit, if you are using quality switches. All the traffic is passed through and handled by the switch, thus no problems.

      If you use a cheap switch, which you most likely won't find with Gbit, you will have problems like this.

      --


      We now return you to your regularly scheduled moment of insanity...
  4. Why avoid little hubs ??? by bstrahm · · Score: 1

    Why should people avoid little hubs around their network ???

    Seems cost effective to me, run one drop to every work location (rather than the 3 you suggest... everyone gets a phone) and save on cabling overall. For the small minority of people that need multiple drops, install a $40 switch on their desktop, this will save you
    1) Managed switch port
    2) Extra cabling costs
    3) Needed space for extra wire running above/below every floor

    Disadvantage - User will have to be responsible for "in cubicle" wiring... Not a bad trade-off since the people needing this will be the more tech savy people to start with

    1. Re:Why avoid little hubs ??? by A_Roche · · Score: 1

      The reason to avoid the small hubs in the cubes, is because now you have additional traffic that you are not planning for. If you plan for a set amount of traffic per connection, then someone goes and hooks a switch or hub to that connection, they are using more bandwidth over that connection than planned. Also there is a limit to how many hops you can go with connections before freaky things start happening. This is hops before the backbone and routers, not from including the backbone. The problem lies with the MAC addressing in switches. I have seen it, and you will spend some time if you don't know what is going on.

      --


      We now return you to your regularly scheduled moment of insanity...
    2. Re:Why avoid little hubs ??? by cmowire · · Score: 4, Insightful

      Generally, you want to avoid little hubs because:
      1) Cheap little hubs tend to have short lifespans, break, have conflicts, etc. They are intended for people's houses, dorm rooms and impromptu networking, not for a business.
      2) Little hubs don't perform so well compared to more ports on the managed switch.
      3) Not everybody who needs multiple computers is tech savy. Take, for example, the salesperson who has a laptop for the road and a desktop for work.
      4) You don't have all of the encryption, authentication, etc. options available for the little hubs.
      5) If the little hub gets messed up, you have to walk to the cube instead of doing everything through a remote admin console.
      6) It costs very little more to run the 3 or 4 drops than it does to run 1 drop. Cable costs pale in comparison to labor costs. It will cost much more to install more drops later when the hubs get to be too annoying.
      7) Managed switch ports, for a good-sized network, are generally pretty cheap. Once you consider the potential hidden costs of a little hub (extra admin trouble, compatability problems, etc) it starts making sense to just use the managed switch ports.

      --
      Gentoo Sucks
    3. Re:Why avoid little hubs ??? by Anonymous Coward · · Score: 0

      Yeah - I've seen a couple situations where cheapo linksys desktop hubs have fried and fucked an entire network. The worst thing is that the link and diag lights were reporting A-OK, while traffic was down to a crawl.

      You certainly haven't saved any money with your $40 part when you've got a couple of $75/hour contract network guys scratching their heads over the issue.

    4. Re:Why avoid little hubs ??? by FLaMeBoY · · Score: 1

      Cmowire is right, putting a hub on each desktop is not realistic. Oh and theres another reason: redundancy. If you have 4 cables running to a desk and say only 2 are used you have 2 spare. Now if you have only one cable to the desk and it breaks, the cost in replacement would probably be equal to the difference between sticking in a single cable and four in the first place. "Measure twice, cut once".

  5. Robotic Cable Puller by AmigaAvenger · · Score: 2, Interesting

    And if you do go with raised floors (good idea!), you will need something capable of pulling new cable runs under the floor, and have some fun doing it! Take a look at the Mark VI

    1. Re:Robotic Cable Puller by HerrNewton · · Score: 1

      it scares me that thing is operating on the same campus as me... i thought a cinderblock chair was bad enough.

      --

      ----
      Am I the only one who thinks Microsoft is a misnomer? Perhaps Macrosoft would be a better fit?
  6. sounds like an upcoming website ... by green+pizza · · Score: 3, Informative

    ... that I've been asked to help with. The URL will eventually be http://networking.beyondboxes.net. Several folks around here, a few even from my company, have been working on it for quite some time. FAQ's, message boards, howtos, and even some insight on the future trends of networking. It should be a great help when it's done sometime in October. Until then, I'll see if I can't dig out some good URLs to paste on this thread.

  7. Even the men's room? by Bazman · · Score: 2

    Yes, even wire up the men's room. That's what happened here. Cables hanging down from the ceiling ready for a network point. Gives a whole new meaning to 'Log on'.

  8. I agree except for... by macdaddy · · Score: 3, Informative

    ...the part about single mode fiber. Within a typical building it's just plain overkill. Multi mode is cheaper, easier to work with, and the transceivers on either end cost so much less than single mode transceivers that it ain't even funny. Multi mode is the safe way to go. String fiber between the closets for sure. The original poster didn't describe their building much (at all?) IIRC. One closet per floor as long as that closet can reach every possible corner of the floor at around 75m. Some push it to the limit, some say 50m. Just be aware of your length; that's the cable tray path, not as the crow flies. Don't forget to allow for jack to CPU cable and patch length too. If you're going to have more than one closet, pick a closet to be the central closet. Say you have 4 floors to wire, 2 closets per floor. String a couple pair of MMF from each closet down to the 1st floor closet and call that your main. Do you best to only have two layers within your building too, if possible. 100FX will probably be more than enough for your infrastructure. GigE is ok too. It costs more though and you have much greater distance limitations. 100FX can run 6,561ft over MMF. GigE can only run 1,443ft over 62.5 micron MMF (the most common) or 1,804ft over 50 micron MMF (double check that last figure). You can always trunk two 100FX lines together. Hell with a wavelength devision multiplexor you can double your bandwidth over the same pair of MMF. Draw a good plan, measure everything, use fiber for your infrastructure, 10/100 to all access ports, put the server got a given area closer to the users it serves, AND buy managed devices. I find the last one to be very important. You can buy Cisco if you want. It's up to you. We're a Cabletron shop (Enterasys now) and are doing fine. I'm not fond of 3Com personally but I know some love them. I really don't like HP. Your choice though. With a managable device, you can monitor and graph bandwidth usage as well as do diagnostics (sniffing via port mirroring) much easier.

  9. my advice by Anonymous Coward · · Score: 0

    I am not a network expert, so take this with a grain of salt....

    The best system is one that lets you add more wiring whenever you want, keeps the cables neat, etc. I know part of it is making sure that you have ample conduit space through the walls, so you can run more cables later on. I know that another part of it is having those faceplates that let you add more jacks....

    Don't run everything through the same conduit set. Running power cables next to network cables is dangerous, stupid, and not good for network reliability....

    cat5 for short runs, fiber for the long haul. Make sure you plan some space on every floor for a wiring closet while you still can; more than one for larger floors....

    Don't forget the absolute minimum is two patches per person (computer, phone), and the minimum will last you about a month before people start bringing in little hubs to put on their desk (which you want to avoid)....

    Put Cat5 everywere, it's cheap, but run it inside ample conduits were you can later on put fiber....

    Anyway, to make a long story short, run todays regular solution everywere, think about upgraded connections for servers, and make sure upgrading is just a matter of buying new cable to run through existing conduits and new switches.

  10. Wireless access points by bluGill · · Score: 2

    don't forget wireless networks. Laptop computers should not be connected to physical ethernet. Get someone who knows wireless to figgure out where acess points should best be placed, and run cables there, (including power, even though that is probably a different person's job)

    Wireless secruity isn't trivial, but it can be done. Wireless is worth it once it works. Give laptops to those who might need them (everyone).