+ Post New Thread
Results 1 to 11 of 11
Wireless Networks Thread, Laser Link bringing down network in Technical; Can anyone shed any light on this problem, possibly someone has had something similar happen? Last year I had a ...
  1. #1
    nip
    nip is offline

    Join Date
    Mar 2008
    Location
    Northampton
    Posts
    7
    Thank Post
    1
    Thanked 0 Times in 0 Posts
    Rep Power
    0

    Laser Link bringing down network

    Can anyone shed any light on this problem, possibly someone has had something similar happen? Last year I had a laser link installed to allow a seperate building access to the network. This was working fine until a couple of weeks ago when all the workstations on the network hung, and rebooting the server had no effect. Thinking it was a switch failure due to the hot weather (server and switches are kept in a small cupboard, gets v. hot in summer months, but at least I was finally able to persuade them to get me an air conditioner unit!) i was troubleshooting along those lines when I realised that all would work well until I plugged in the patch cable running (via a POE injector) to the laser unit, carrying out a continuous ping to the router from the server whilst plugging unit in and out confirmed it was dropping the connection when plugged in. As far as I am aware, the laser unit doesn't use an IP address as its just a medium to transfer data (as is a normal cat5 cable), I've even terminated the link into a different patch panel with no difference. Just can't understand why this would affect the link to the router, they're not even on the same segment of the network, anyone think of something else I can try?

  2. #2

    Geoff's Avatar
    Join Date
    Jun 2005
    Location
    Fylde, Lancs, UK.
    Posts
    11,803
    Thank Post
    110
    Thanked 583 Times in 504 Posts
    Blog Entries
    1
    Rep Power
    224
    network loop at the far end of the link?

  3. #3

    Join Date
    Jan 2006
    Location
    Liverpool
    Posts
    84
    Thank Post
    30
    Thanked 13 Times in 12 Posts
    Rep Power
    20
    Or as we were told once ("the building must have moved with the heat") causing loss of link. Still laugh about that....

  4. #4
    bizzel's Avatar
    Join Date
    Jul 2007
    Location
    Cambridge
    Posts
    654
    Thank Post
    102
    Thanked 204 Times in 72 Posts
    Rep Power
    51
    Just a thought. What would happen if an eagle-eyed student managed to bring in a laser pointer and hit one of the units?

  5. #5


    Join Date
    Feb 2007
    Location
    Northamptonshire
    Posts
    4,692
    Thank Post
    352
    Thanked 797 Times in 716 Posts
    Rep Power
    347
    They'd get a marksman at Bisley!

  6. #6
    ICTNUT's Avatar
    Join Date
    Jul 2005
    Location
    Hereford
    Posts
    1,419
    Thank Post
    196
    Thanked 249 Times in 122 Posts
    Rep Power
    62
    Can you tell us what units you are using??

    We have a number of LaserBit links and have never had issues with these from the point I installed them no matter what the weather.

    We have had kids try to break the beams but they never manage to cause any issues.

  7. #7

    Join Date
    Aug 2005
    Location
    London
    Posts
    3,157
    Thank Post
    116
    Thanked 529 Times in 452 Posts
    Blog Entries
    2
    Rep Power
    124
    Quote Originally Posted by ICTNUT View Post
    We have a number of LaserBit links and have never had issues with these from the point I installed them no matter what the weather.

    We have had kids try to break the beams but they never manage to cause any issues.
    Ours were generally reliable except in fog (which London gets too much of in early mornings in the autumn) and on one occasion when snow blew directly onto the front of the unit.

    Dare I ask how kids were trying to break the beams? Are they near ground level?

  8. #8
    nip
    nip is offline

    Join Date
    Mar 2008
    Location
    Northampton
    Posts
    7
    Thank Post
    1
    Thanked 0 Times in 0 Posts
    Rep Power
    0
    Thanks for the replies, chaps. These are 100Mbps Laserbit units. I've tried disconnecting the far end, and even tested the POE injector from the other building in the main building with the same results, I admit the symptoms seem to suggest a loopback issue, but i've isolated it to just that link so it must be either a faulty cable, or the laserbit unit itself. I'm going to try and bypass the cable next week during half term to see if this works, if not, it must be the laserbit unit itself causing the problem, would you agree?
    As for pupils sabotaging the system, it does raise an interesting point doesn't it, were a special school so while I have doubts about our kids doing this, you should never say never, as the saying goes!

  9. #9

    Geoff's Avatar
    Join Date
    Jun 2005
    Location
    Fylde, Lancs, UK.
    Posts
    11,803
    Thank Post
    110
    Thanked 583 Times in 504 Posts
    Blog Entries
    1
    Rep Power
    224
    Quote Originally Posted by ICTNUT View Post
    We have had kids try to break the beams but they never manage to cause any issues.
    Heh, I have an image of a kid jumping up, hand outstretched, only to have it burst into flames as soon as he makes contact with the laser beam.

  10. #10
    bizzel's Avatar
    Join Date
    Jul 2007
    Location
    Cambridge
    Posts
    654
    Thank Post
    102
    Thanked 204 Times in 72 Posts
    Rep Power
    51


    On a serious note, I'd suggest that either the cable or unit has failed. How are they powered and can you reset them?

  11. #11
    nip
    nip is offline

    Join Date
    Mar 2008
    Location
    Northampton
    Posts
    7
    Thank Post
    1
    Thanked 0 Times in 0 Posts
    Rep Power
    0
    They're power over ethernet (using 3Com injectors), and I didn't see a reset button on the laser unit although I was wobbling about on my rickety set of ladders and not really looking, I'll see what I can find again today when I bypass the cabling.

SHARE:
+ Post New Thread

Similar Threads

  1. Microwave / Laser Link to another building - any recommendations?
    By bandgeekmafia78 in forum Network and Classroom Management
    Replies: 5
    Last Post: 10th April 2008, 06:16 PM
  2. Good Network Colour Laser
    By button_ripple in forum Hardware
    Replies: 12
    Last Post: 9th March 2008, 01:35 PM
  3. Replies: 10
    Last Post: 7th January 2008, 02:39 PM
  4. Replies: 3
    Last Post: 17th December 2007, 07:49 PM
  5. Bringing Linux To The Students
    By Pear in forum *nix
    Replies: 20
    Last Post: 27th June 2006, 12:09 PM

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •