Gigabit connectivity

Posted on 2006-05-30
Last Modified: 2010-05-18
This is for you electrical engineering types...  I've inherited a network with cisco 10/100 switches, however for a complicated reason (and lack of foresight) the wall jacks are all cat5 wired with only wires 1,2,3 and 6.  4,5 and 7,8 were used for phone connections.

We're a hotel, so when a guest arrives with their laptop, it works fine UNLESS they have a newer laptop with a gigabit NIC thats set to autosense.  When they connect that, the NIC doesn't display a link light at all.   However, if I go into the driver for the NIC and tell is to use 10 or 100 mb instead of autosense, it works every time.

So obviously I need to fix something... and my predecessor is gone so I can't "fix" him like a vet ;)

My question is whether to put gigabit switches on the bastardized wiring and then it will work, or to rewire and keep my 10/100 switches.  I'm wondering if the lack of two pair in the jack is really causing this... or if the problem isn't the wiring but the switches.  I have basically one shot to get it working... can't afford to do wiring and switches at the same time (though I know thats the ultimate solution).

Question by:alanvranian
    LVL 26

    Accepted Solution

    Keep your switches and fix the cabling. Yes this probably is most likely caused by the crappy cabling job. I don't think putting gigabit switches in will do anything either. Gigabit cabling requires a close compliance to the standards, and since the rooms already don't live up to any standards you wouldn't get gigabit speeds anyway.  
    LVL 1

    Assisted Solution

    Also make sure non of your machines have any viruses or spyware on them. I had one client a few weeks back that was riddled with spyware. I completeley cleaned his system, and alomost instaneously, the network performance got better, as his machine was chucking out lot of unecessary traffic.


    LVL 95

    Assisted Solution

    by:Lee W, MVP
    A gigabit switch will not help you - gigabit uses all 4 pairs of wires.  (reference: ) The problem is the phone signals are probably tricking the gigabit ethernet ports on the newer laptops into thinking they are on a gigabit connection because there's "activity" on the wires where there shouldn't be any if it were only 100 Mbit.

    If you want this problem fixed, you need to rewire the building.  Not fun, but that's what needs to be done.
    LVL 5

    Assisted Solution

    I would just add this note to the hotel's "Internet usage" brochure - its really easy, this way u don't need to fix anything.

    I would say the reasons for such decision could be:

    1. Your switches don't get more than 100Mbps anyway - no need for gigabit switches
    2. rewiring will be really costly

    may be instead of rewiring - add  WiFi access points infrastructure - this will save you a lot of money.

    Author Comment

    Thanks to all of you for the confirmation of what I suspected, and honorable mention to leew for offering some supporting documents.  I wish that the answer were easier to accomplish.

    I am rolling out Wireless in all 25 buildings, however we have a certain amount of high level military use of our network and they aren't allowed to do wireless that isn't provided by DISA ... so I'm still facing wiring.

    Shortcuts never pay...  proof positive.

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