Saturday, January 29, 2011

What is the fastest way to connect two separate networks within two separate buildings?

We have two buildings that are across the street from each other. Each has their own separate network. We needed to connect them together using a fast connection because of the large number of files that are copied between the networks on a daily basis. We have a wireless bridge setup right now between the buildings that gives us about 20Mbps (it's two Aironet 1240AG in root/non-root configuration).

Unfortunately there's a lot of RF interference in the area (lots of residential buildings) and the Aironet's lose connectivity on a daily basis (which leads to a lot of disgruntled users). I'm thinking about upgrading to some Motorola PTP wireless bridges but I wanted to ask, am I going about this the right way? We went with the wireless bridges because it was cheaper than getting a hard line between the two buildings but I'm starting to regret that idea given how badly these AP's are working. Any suggestions?

Edit: The Aironet's are using the 5Ghz band and use 802.11a. The antennas are directional panel antennas.

  • If you've got line of sight, there's some neat laser and directed microwave gear available. It ain't cheap, but it's fast and pretty reliable. Your best bet, though, from a speed and reliability standpoint is always going to be physical copper or glass, but you need to make the cost/benefit call yourself after researching the options for your particular circumstances and weighing them up.

    From womble
  • My suggestions:

    1. Switch to Wireless-N band (i recommend the $35 dlink DIR-615 router or a more expensive one if you need to swap for a bigger antenna)

    and/or

    1. Use a DD-WRT repeater to extend the range (for n-band, use a cisco wrt300n for about $45)
    ErikA : He mentioned that there is a lot of RFI in his area. As such, upgrading to N isn't necessarily going to help him. A good recommendation will need to be something that either 1) moves away from commodity RF gear to something in a licensed (or less used) spectrum or 2) otherwise limits the RF interference (think two very tight directional antennas).
    ctuffli : In defense of the commenter, RF interference takes many forms. I've seen environments with a ton of 2.4GHz interference but with little to no 5GHz interference. In these cases, switching to a 5GHz 802.11n solution might work. For a business environment, I wouldn't skimp on the gear.
    djangofan : an N network at 20% has 3 times the bandwidth of a G network at 20%. RFI doesn't mean that its impossible. changing wireless channel , etc., can solve that issue. no reason to give me minus votes for trying to help with a realistic answer.
    Zypher : DD-WRT/tomato do not magically change consumer grade hardware into enterprise grade hardware.
    djangofan : no, it does not. what it does is turn it into the easiest REPEATER device that there is.
    From djangofan
  • Every "fixed wireless" installation I've seen with has always ended up being a pain (too slow, susceptible to intereference and therefore unreliable, prone to failures of gear, lightning strikes, etc). Assuming you're going to remain in these buildings for a long enough period of time to amortize the cost, get some fiber run. You won't regret it. Once fiber is in the ground / air and terminated, barring any physical damage (backhoe-induced-fiber-failure, gunshot, etc) it'll work virtually forever.

    If you're lucky, you're under 500 meters or so, and can use multimode fiber and multimode transceivers / GBICs. Multimode fiber and the termination electronics are significantly cheaper than single-mode.

    mh : +1, fiber, fiber, fiber.
    djangofan : unrealistic answer. far too expensive for this guy. running that wire across underground would cost $1000 + . this answer doesnt deserve upvotes.
    MikeyB : Unrealistic? He didn't ask for the cheapest. Fiber is the fastest and most reliable way of doing it.
    Evan Anderson : @djangofan: My experience has been that fiber ends up being the cheapest answer if you need high speed, reliable, and long-term connectivity between buildings. High-end wireless gear isn't inexpensive at all, and installation typically requires mounting antennas and running cable. After your radios take a lightning strike or two, or after users become disgruntled / lose productivity because the connection is dodgy, you begin to see that the "expense" of fiber up-front pays off in the long term.
    Zypher : @djangofan: he is already running Aironets - those baby's aint cheap my supplier shows them @ ~$480/ea ... so he has ALREADY spent ~$1000.
    zippy : I'm going to get quotes on how much it would cost to run a physical point to point connection between the buildings. If the prices aren't heart attack inducing I'll give you credit for this answer.
    Evan Anderson : @zippy: So, it wasn't heart attack inducing, eh? Seriously, though, did the fiber quotes come in anywhere close to reasonable for your budget?
    zippy : The quotes were in the $1400-1700/month range with a $600-$1000 buildout fee. I was expecting about $2k/mon. It's cheaper than bonding 6 T1s together I guess.
  • These may not be cheaper than a fiber run; but you can get gigabit throughput with these. We put up a 800 meter link with them and they've been solid.

    3dinfluence : Those look pretty interesting.
    From Eddy
  • try lightpointe

    http://www.lightpointe.com/home.cfm

    In this website... I primarily meant the laser beam products... however, I do see that recently they have introduced products similar to Bridgewave...

  • Not sure what Motorola equipment you were looking, but you might compare it to Cisco's outdoor Aironet bridges. These will be better suited to the task than the 1240AG's that you already have. See the 1300 Series and 1400 Series.

    The 1400's are probably overkill for your situation but I have 4 set up to create a redundant link between two sites approximately a quarter mile away from each other. We have them inside their respective buildings and are actually shooting through several roof lines. I don't have any performance figures handy but the two sites might as well be on the same lan. Ping times are normally 2 ms.

    As others have mentioned if you stick with wireless it needs to be directional.

    From sdanelson
  • I strongly agree with the fiber suggestion; I'll only add that, if the distance between the two buildings is under 100 meters, you can use CAT-6 cable instead of fiber and still have gigabit throughput.

    Evan Anderson : +1 - Very reasonable, assuming you use an outdoor-rated cable installed to code and have lightning arrestors on the ends of the cable.
    From Massimo

0 comments:

Post a Comment