Always one PC dropping out intermittently no matter what I try....

Discussion in 'Wireless Networking' started by Philip Herlihy, Jul 27, 2007.

  1. I have a customer with a small office on three floors, with about a
    dozen PCs and laptops, and a a couple of PCs and printers hard-wired.

    The heart of the network is a Netgear FVS114 firewall providing DHCP.
    There's a hub feeding a Thomson ST180 wireless access point (ground
    floor), and a cable link to the 2nd floor feeding a Netgear WG602v3
    access point. The PCs have AT-WCP200G PCI wireless cards.

    Whatever I've tried over the last few months (!) there always seems to
    be one PC or other which can't stay on the network. Some never seem to
    have a problem, but the problem seems to shift around the ones which do.

    The firewall was replaced recently (identical unit) which improved
    reliability of the network overall. I've also found that one of the
    links from the ground to the 2nd floor (note there's a 1st floor in
    between - I'm in the UK!) has an intermittent open-circuit at one
    socket; the other seems ok.

    Most PCs, downstairs and upstairs, can bind to the Thomson ST180 and
    keep a stable connection, except for one downstairs (which usually can't
    see any wireless networks) and one upstairs. I've tried reloading
    drivers, extension antenna, switching round the WAPs, bringing both
    downstairs - no improvement.

    I thought I was onto something when I bought WirelessMon, which showed
    about 8 wireless networks, all only intermittently available except for
    the Thomson ST180 (about -45dB). The Netgear WG602v3 is much stronger
    upstairs (that's where it lives) at about -15dB, but WirelessMon shows
    it coming and going several times a minute, seen through the wireless
    card of one machine which manages a steady connection to the ST180 two
    floors below. Another nearby machine can't get a steady hold on the
    downstairs WAP, and can't bind to the upstairs one.

    I replaced the Netgear WG602v3 with a US Robotics USR5416. No
    improvement: the signal in WirelessMon was still shown as coming and
    going while the downstairs ST180 was steady as a rock.

    Changing channel on the downstairs ST180 allowed one PC to get a
    connection but another one lost it, so I changed back, restoring the
    previous situation.

    I disabled the PCI card on the "unlucky" PC upstairs and fitted a US
    Robotics USR5420 adapter, which was able to bind to the weak signal from
    downstairs, but not the Netgear WG602v3 upstairs. Substituting the
    USR5416 again (configured so that it's possible just to switch the
    boxes) produced a loss of ability to bind to the ground floor in the PC
    with the USR5420 USB adapter, and it couldn't bind to the USR5416.

    Today I've tried fiddling with the various settings on the (reinstated)
    Netgear WG602v3. While the downstairs ST180 remains on WEP (128), I
    switched the WG602v3 to WPA-PSK. No improvement. I've also tried
    reducing the data rate from "Best" to 24Mb/s, and changed from "g or b"
    to "g only". No improvement.

    Meanwhile, a network in their other office with a single Thomson ST180
    and 8 of the same PCI cards soldiers on without a blink. If I could get
    another ST180 I would!

    So, the only thing I can think of is to start replacing the wireless PCI
    cards, inclining towards US Robotics. However, if you've been generous
    enough to read this far and can suggest ANYTHING else worth trying, I'll
    be greatly indebted to you.

    Phil, London
     
    Philip Herlihy, Jul 27, 2007
    #1
    1. Advertising

  2. Philip Herlihy wrote:
    > I have a customer with a small office on three floors, with about a
    > dozen PCs and laptops, and a a couple of PCs and printers hard-wired.
    >
    > The heart of the network is a Netgear FVS114 firewall providing DHCP.
    > There's a hub feeding a Thomson ST180 wireless access point (ground
    > floor), and a cable link to the 2nd floor feeding a Netgear WG602v3
    > access point. The PCs have AT-WCP200G PCI wireless cards.
    >
    > Whatever I've tried over the last few months (!) there always seems to
    > be one PC or other which can't stay on the network. Some never seem to
    > have a problem, but the problem seems to shift around the ones which do.
    >
    > The firewall was replaced recently (identical unit) which improved
    > reliability of the network overall. I've also found that one of the
    > links from the ground to the 2nd floor (note there's a 1st floor in
    > between - I'm in the UK!) has an intermittent open-circuit at one
    > socket; the other seems ok.
    >
    > Most PCs, downstairs and upstairs, can bind to the Thomson ST180 and
    > keep a stable connection, except for one downstairs (which usually can't
    > see any wireless networks) and one upstairs. I've tried reloading
    > drivers, extension antenna, switching round the WAPs, bringing both
    > downstairs - no improvement.
    >
    > I thought I was onto something when I bought WirelessMon, which showed
    > about 8 wireless networks, all only intermittently available except for
    > the Thomson ST180 (about -45dB). The Netgear WG602v3 is much stronger
    > upstairs (that's where it lives) at about -15dB, but WirelessMon shows
    > it coming and going several times a minute, seen through the wireless
    > card of one machine which manages a steady connection to the ST180 two
    > floors below. Another nearby machine can't get a steady hold on the
    > downstairs WAP, and can't bind to the upstairs one.
    >
    > I replaced the Netgear WG602v3 with a US Robotics USR5416. No
    > improvement: the signal in WirelessMon was still shown as coming and
    > going while the downstairs ST180 was steady as a rock.
    >
    > Changing channel on the downstairs ST180 allowed one PC to get a
    > connection but another one lost it, so I changed back, restoring the
    > previous situation.
    >
    > I disabled the PCI card on the "unlucky" PC upstairs and fitted a US
    > Robotics USR5420 adapter, which was able to bind to the weak signal from
    > downstairs, but not the Netgear WG602v3 upstairs. Substituting the
    > USR5416 again (configured so that it's possible just to switch the
    > boxes) produced a loss of ability to bind to the ground floor in the PC
    > with the USR5420 USB adapter, and it couldn't bind to the USR5416.
    >
    > Today I've tried fiddling with the various settings on the (reinstated)
    > Netgear WG602v3. While the downstairs ST180 remains on WEP (128), I
    > switched the WG602v3 to WPA-PSK. No improvement. I've also tried
    > reducing the data rate from "Best" to 24Mb/s, and changed from "g or b"
    > to "g only". No improvement.
    >
    > Meanwhile, a network in their other office with a single Thomson ST180
    > and 8 of the same PCI cards soldiers on without a blink. If I could get
    > another ST180 I would!
    >
    > So, the only thing I can think of is to start replacing the wireless PCI
    > cards, inclining towards US Robotics. However, if you've been generous
    > enough to read this far and can suggest ANYTHING else worth trying, I'll
    > be greatly indebted to you.
    >
    > Phil, London



    Update from OP. I've just "found" Wireshark and Netstumbler, which I'll
    be trying out next week. Any pointers to their use will also be greatly
    valued.

    Phil
     
    Philip Herlihy, Jul 27, 2007
    #2
    1. Advertising

  3. Philip Herlihy wrote:
    > Philip Herlihy wrote:
    >> I have a customer with a small office on three floors, with about a
    >> dozen PCs and laptops, and a a couple of PCs and printers hard-wired.
    >>
    >> The heart of the network is a Netgear FVS114 firewall providing DHCP.
    >> There's a hub feeding a Thomson ST180 wireless access point (ground
    >> floor), and a cable link to the 2nd floor feeding a Netgear WG602v3
    >> access point. The PCs have AT-WCP200G PCI wireless cards.
    >>
    >> Whatever I've tried over the last few months (!) there always seems to
    >> be one PC or other which can't stay on the network. Some never seem
    >> to have a problem, but the problem seems to shift around the ones
    >> which do.
    >>
    >> The firewall was replaced recently (identical unit) which improved
    >> reliability of the network overall. I've also found that one of the
    >> links from the ground to the 2nd floor (note there's a 1st floor in
    >> between - I'm in the UK!) has an intermittent open-circuit at one
    >> socket; the other seems ok.
    >>
    >> Most PCs, downstairs and upstairs, can bind to the Thomson ST180 and
    >> keep a stable connection, except for one downstairs (which usually
    >> can't see any wireless networks) and one upstairs. I've tried
    >> reloading drivers, extension antenna, switching round the WAPs,
    >> bringing both downstairs - no improvement.
    >>
    >> I thought I was onto something when I bought WirelessMon, which showed
    >> about 8 wireless networks, all only intermittently available except
    >> for the Thomson ST180 (about -45dB). The Netgear WG602v3 is much
    >> stronger upstairs (that's where it lives) at about -15dB, but
    >> WirelessMon shows it coming and going several times a minute, seen
    >> through the wireless card of one machine which manages a steady
    >> connection to the ST180 two floors below. Another nearby machine
    >> can't get a steady hold on the downstairs WAP, and can't bind to the
    >> upstairs one.
    >>
    >> I replaced the Netgear WG602v3 with a US Robotics USR5416. No
    >> improvement: the signal in WirelessMon was still shown as coming and
    >> going while the downstairs ST180 was steady as a rock.
    >>
    >> Changing channel on the downstairs ST180 allowed one PC to get a
    >> connection but another one lost it, so I changed back, restoring the
    >> previous situation.
    >>
    >> I disabled the PCI card on the "unlucky" PC upstairs and fitted a US
    >> Robotics USR5420 adapter, which was able to bind to the weak signal
    >> from downstairs, but not the Netgear WG602v3 upstairs. Substituting
    >> the USR5416 again (configured so that it's possible just to switch
    >> the boxes) produced a loss of ability to bind to the ground floor in
    >> the PC with the USR5420 USB adapter, and it couldn't bind to the USR5416.
    >>
    >> Today I've tried fiddling with the various settings on the
    >> (reinstated) Netgear WG602v3. While the downstairs ST180 remains on
    >> WEP (128), I switched the WG602v3 to WPA-PSK. No improvement. I've
    >> also tried reducing the data rate from "Best" to 24Mb/s, and changed
    >> from "g or b" to "g only". No improvement.
    >>
    >> Meanwhile, a network in their other office with a single Thomson ST180
    >> and 8 of the same PCI cards soldiers on without a blink. If I could
    >> get another ST180 I would!Ba
    >>
    >> So, the only thing I can think of is to start replacing the wireless
    >> PCI cards, inclining towards US Robotics. However, if you've been
    >> generous enough to read this far and can suggest ANYTHING else worth
    >> trying, I'll be greatly indebted to you.
    >>
    >> Phil, London

    >
    >
    > Update from OP. I've just "found" Wireshark and Netstumbler, which I'll
    > be trying out next week. Any pointers to their use will also be greatly
    > valued.
    >
    > Phil


    Baffled by Wireshark, but Netstumbler shows the 2nd floor WG602v3 to
    have a max Signal-to-Noise-Ratio of 86, significantly above any of the
    others. Yet only the ground floor ST180 holds steady, with the
    next-highest max SNR of 55. All the other signals lose availability
    frequently.

    Phil
     
    Philip Herlihy, Jul 27, 2007
    #3
  4. Hi
    I do not know he traffic condition of this, but if it is peer to peer the
    amount of PCs start to exceed efficient usage of the Network.
    Switching to Windows 2003 SBS and to mid level Wireless (like Proxim Access
    Points) should be considered.
    Jack (MVP-Networking).

    "Philip Herlihy" <> wrote in message
    news:f8dk8u$2fj$1$...
    >I have a customer with a small office on three floors, with about a dozen
    >PCs and laptops, and a a couple of PCs and printers hard-wired.
    >
    > The heart of the network is a Netgear FVS114 firewall providing DHCP.
    > There's a hub feeding a Thomson ST180 wireless access point (ground
    > floor), and a cable link to the 2nd floor feeding a Netgear WG602v3 access
    > point. The PCs have AT-WCP200G PCI wireless cards.
    >
    > Whatever I've tried over the last few months (!) there always seems to be
    > one PC or other which can't stay on the network. Some never seem to have
    > a problem, but the problem seems to shift around the ones which do.
    >
    > The firewall was replaced recently (identical unit) which improved
    > reliability of the network overall. I've also found that one of the links
    > from the ground to the 2nd floor (note there's a 1st floor in between -
    > I'm in the UK!) has an intermittent open-circuit at one socket; the other
    > seems ok.
    >
    > Most PCs, downstairs and upstairs, can bind to the Thomson ST180 and keep
    > a stable connection, except for one downstairs (which usually can't see
    > any wireless networks) and one upstairs. I've tried reloading drivers,
    > extension antenna, switching round the WAPs, bringing both downstairs - no
    > improvement.
    >
    > I thought I was onto something when I bought WirelessMon, which showed
    > about 8 wireless networks, all only intermittently available except for
    > the Thomson ST180 (about -45dB). The Netgear WG602v3 is much stronger
    > upstairs (that's where it lives) at about -15dB, but WirelessMon shows it
    > coming and going several times a minute, seen through the wireless card of
    > one machine which manages a steady connection to the ST180 two floors
    > below. Another nearby machine can't get a steady hold on the downstairs
    > WAP, and can't bind to the upstairs one.
    >
    > I replaced the Netgear WG602v3 with a US Robotics USR5416. No
    > improvement: the signal in WirelessMon was still shown as coming and going
    > while the downstairs ST180 was steady as a rock.
    >
    > Changing channel on the downstairs ST180 allowed one PC to get a
    > connection but another one lost it, so I changed back, restoring the
    > previous situation.
    >
    > I disabled the PCI card on the "unlucky" PC upstairs and fitted a US
    > Robotics USR5420 adapter, which was able to bind to the weak signal from
    > downstairs, but not the Netgear WG602v3 upstairs. Substituting the
    > USR5416 again (configured so that it's possible just to switch the boxes)
    > produced a loss of ability to bind to the ground floor in the PC with the
    > USR5420 USB adapter, and it couldn't bind to the USR5416.
    >
    > Today I've tried fiddling with the various settings on the (reinstated)
    > Netgear WG602v3. While the downstairs ST180 remains on WEP (128), I
    > switched the WG602v3 to WPA-PSK. No improvement. I've also tried
    > reducing the data rate from "Best" to 24Mb/s, and changed from "g or b" to
    > "g only". No improvement.
    >
    > Meanwhile, a network in their other office with a single Thomson ST180 and
    > 8 of the same PCI cards soldiers on without a blink. If I could get
    > another ST180 I would!
    >
    > So, the only thing I can think of is to start replacing the wireless PCI
    > cards, inclining towards US Robotics. However, if you've been generous
    > enough to read this far and can suggest ANYTHING else worth trying, I'll
    > be greatly indebted to you.
    >
    > Phil, London
     
    Jack \(MVP-Networking\)., Jul 28, 2007
    #4
  5. Thanks for the reply! Strictly-speaking, the network is peer-to-peer,
    in that there are no true servers, but in practice two PCs (one
    hard-wired on the ground floor, and one wireless on the 2nd floor)
    provided file-sharing and a crude intranet. Or should I be thinking of
    the wireless environment? It's the 2nd floor that has the most pressing
    problem: one small room with 5 wireless PCs and a laptop. Would it help
    to force all PCs to bind only to Access Points? (Haven't checked all
    PCs for this)

    Is there any way of measuring the problems you suggest?

    Phil


    Jack (MVP-Networking). wrote:
    > Hi
    > I do not know he traffic condition of this, but if it is peer to peer
    > the amount of PCs start to exceed efficient usage of the Network.
    > Switching to Windows 2003 SBS and to mid level Wireless (like Proxim
    > Access Points) should be considered.
    > Jack (MVP-Networking).
    >
    > "Philip Herlihy" <> wrote in message
    > news:f8dk8u$2fj$1$...
    >> I have a customer with a small office on three floors, with about a
    >> dozen PCs and laptops, and a a couple of PCs and printers hard-wired.
    >>
    >> The heart of the network is a Netgear FVS114 firewall providing DHCP.
    >> There's a hub feeding a Thomson ST180 wireless access point (ground
    >> floor), and a cable link to the 2nd floor feeding a Netgear WG602v3
    >> access point. The PCs have AT-WCP200G PCI wireless cards.
    >>
    >> Whatever I've tried over the last few months (!) there always seems to
    >> be one PC or other which can't stay on the network. Some never seem
    >> to have a problem, but the problem seems to shift around the ones
    >> which do.
    >>
    >> The firewall was replaced recently (identical unit) which improved
    >> reliability of the network overall. I've also found that one of the
    >> links from the ground to the 2nd floor (note there's a 1st floor in
    >> between - I'm in the UK!) has an intermittent open-circuit at one
    >> socket; the other seems ok.
    >>
    >> Most PCs, downstairs and upstairs, can bind to the Thomson ST180 and
    >> keep a stable connection, except for one downstairs (which usually
    >> can't see any wireless networks) and one upstairs. I've tried
    >> reloading drivers, extension antenna, switching round the WAPs,
    >> bringing both downstairs - no improvement.
    >>
    >> I thought I was onto something when I bought WirelessMon, which showed
    >> about 8 wireless networks, all only intermittently available except
    >> for the Thomson ST180 (about -45dB). The Netgear WG602v3 is much
    >> stronger upstairs (that's where it lives) at about -15dB, but
    >> WirelessMon shows it coming and going several times a minute, seen
    >> through the wireless card of one machine which manages a steady
    >> connection to the ST180 two floors below. Another nearby machine
    >> can't get a steady hold on the downstairs WAP, and can't bind to the
    >> upstairs one.
    >>
    >> I replaced the Netgear WG602v3 with a US Robotics USR5416. No
    >> improvement: the signal in WirelessMon was still shown as coming and
    >> going while the downstairs ST180 was steady as a rock.
    >>
    >> Changing channel on the downstairs ST180 allowed one PC to get a
    >> connection but another one lost it, so I changed back, restoring the
    >> previous situation.
    >>
    >> I disabled the PCI card on the "unlucky" PC upstairs and fitted a US
    >> Robotics USR5420 adapter, which was able to bind to the weak signal
    >> from downstairs, but not the Netgear WG602v3 upstairs. Substituting
    >> the USR5416 again (configured so that it's possible just to switch
    >> the boxes) produced a loss of ability to bind to the ground floor in
    >> the PC with the USR5420 USB adapter, and it couldn't bind to the USR5416.
    >>
    >> Today I've tried fiddling with the various settings on the
    >> (reinstated) Netgear WG602v3. While the downstairs ST180 remains on
    >> WEP (128), I switched the WG602v3 to WPA-PSK. No improvement. I've
    >> also tried reducing the data rate from "Best" to 24Mb/s, and changed
    >> from "g or b" to "g only". No improvement.
    >>
    >> Meanwhile, a network in their other office with a single Thomson ST180
    >> and 8 of the same PCI cards soldiers on without a blink. If I could
    >> get another ST180 I would!
    >>
    >> So, the only thing I can think of is to start replacing the wireless
    >> PCI cards, inclining towards US Robotics. However, if you've been
    >> generous enough to read this far and can suggest ANYTHING else worth
    >> trying, I'll be greatly indebted to you.
    >>
    >> Phil, London

    >
     
    Philip Herlihy, Jul 28, 2007
    #5
  6. Re: Always one PC dropping out intermittently no matter what I try....(screenshot)

    Philip Herlihy wrote:
    > I have a customer with a small office on three floors, with about a
    > dozen PCs and laptops, and a a couple of PCs and printers hard-wired.
    >
    > The heart of the network is a Netgear FVS114 firewall providing DHCP.
    > There's a hub feeding a Thomson ST180 wireless access point (ground
    > floor), and a cable link to the 2nd floor feeding a Netgear WG602v3
    > access point. The PCs have AT-WCP200G PCI wireless cards.
    >
    > Whatever I've tried over the last few months (!) there always seems to
    > be one PC or other which can't stay on the network. Some never seem to
    > have a problem, but the problem seems to shift around the ones which do.
    >
    > The firewall was replaced recently (identical unit) which improved
    > reliability of the network overall. I've also found that one of the
    > links from the ground to the 2nd floor (note there's a 1st floor in
    > between - I'm in the UK!) has an intermittent open-circuit at one
    > socket; the other seems ok.
    >
    > Most PCs, downstairs and upstairs, can bind to the Thomson ST180 and
    > keep a stable connection, except for one downstairs (which usually can't
    > see any wireless networks) and one upstairs. I've tried reloading
    > drivers, extension antenna, switching round the WAPs, bringing both
    > downstairs - no improvement.
    >
    > I thought I was onto something when I bought WirelessMon, which showed
    > about 8 wireless networks, all only intermittently available except for
    > the Thomson ST180 (about -45dB). The Netgear WG602v3 is much stronger
    > upstairs (that's where it lives) at about -15dB, but WirelessMon shows
    > it coming and going several times a minute, seen through the wireless
    > card of one machine which manages a steady connection to the ST180 two
    > floors below. Another nearby machine can't get a steady hold on the
    > downstairs WAP, and can't bind to the upstairs one.
    >
    > I replaced the Netgear WG602v3 with a US Robotics USR5416. No
    > improvement: the signal in WirelessMon was still shown as coming and
    > going while the downstairs ST180 was steady as a rock.
    >
    > Changing channel on the downstairs ST180 allowed one PC to get a
    > connection but another one lost it, so I changed back, restoring the
    > previous situation.
    >
    > I disabled the PCI card on the "unlucky" PC upstairs and fitted a US
    > Robotics USR5420 adapter, which was able to bind to the weak signal from
    > downstairs, but not the Netgear WG602v3 upstairs. Substituting the
    > USR5416 again (configured so that it's possible just to switch the
    > boxes) produced a loss of ability to bind to the ground floor in the PC
    > with the USR5420 USB adapter, and it couldn't bind to the USR5416.
    >
    > Today I've tried fiddling with the various settings on the (reinstated)
    > Netgear WG602v3. While the downstairs ST180 remains on WEP (128), I
    > switched the WG602v3 to WPA-PSK. No improvement. I've also tried
    > reducing the data rate from "Best" to 24Mb/s, and changed from "g or b"
    > to "g only". No improvement.
    >
    > Meanwhile, a network in their other office with a single Thomson ST180
    > and 8 of the same PCI cards soldiers on without a blink. If I could get
    > another ST180 I would!
    >
    > So, the only thing I can think of is to start replacing the wireless PCI
    > cards, inclining towards US Robotics. However, if you've been generous
    > enough to read this far and can suggest ANYTHING else worth trying, I'll
    > be greatly indebted to you.
    >
    > Phil, London


    Captured a screenshot from NetStumber here:

    http://homepages.rya-online.net/pherlihy/NetStumblerScreenshot.gif

    26 networks detected after an hour's running. I've sorted by max SNR
    (Signal to Noise Ratio) although I'm not certain the "noise" part of
    that value is being correctly reported. Coincides with max Signal, though.

    Just one signal stays steady as a rock, and it isn't the strongest!

    Phil
     
    Philip Herlihy, Jul 28, 2007
    #6
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