Gigabit network slowssss down to ~ 100MBit

Discussion in 'Server Networking' started by >>KY, Dec 6, 2007.

  1. >>KY

    >>KY Guest

    I have a 30 user environment with gigabit switches and Windows 2003 SP2 R2
    everywhere (6 servers). As of two weeks ago, everything with gigabit nic
    were transferring at that speed (including some desktops); however, this
    week I noticed it has slowed to maybe 100 Gb. The only thing that has
    changed that I can recall is that our 2 T1 lines were bonded; our ISP
    replaced the 2 AdTrans they had and added a Cisco router for the ISP gateway
    and we added a Sonicwall 2040 Pro for our internal gateway.

    (1) How could that changed do anything with our internal switches which are
    Gigabit port switches?

    (2) How can I determine which ports / device is causing the slowdown?
    Meaning how or what can I test on network to see the offending device?
    >>KY, Dec 6, 2007
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  2. >>KY

    SeriousSam Guest

    Hard to guess at, sounds like interference or jinky cabling to me. the first
    thing I would do is buy a couple of high quality machine fabricated CAT6
    cables and replace any main cables (i.e. switch to switch, ect) and see if
    that helps. Also look for any new sources of interference. Did you move a
    cable run closer to a flourescent light fixture or install a new fixture near
    a cable? Check your choke points. I am assuming you have more than one switch
    from your writing. Do any clients still operate at GB speed across the LAN?
    If some yes and some no, maybe you have a fluky switch.
    SeriousSam, Dec 7, 2007
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  3. >>KY

    PKilian Guest


    I'd check the Sonicwall first, I use them here. When you say that it is
    used for your internal firewall does all your internal traffic go through it?
    If so, do you have any encrption turned on or are you doing deep packet
    inspection? If so, you are never going to get gigabit performance out if it.

    Best Regards.
    PKilian, Dec 11, 2007
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