Wireless Networks Thread, HP 6720s + Network ONLY in certain areas... in Technical; I'm having a very odd problem with one of our staff laptops...
It's an HP 6720s, the teacher brought it ...
14th September 2008, 07:25 PM #1
HP 6720s + Network ONLY in certain areas...
I'm having a very odd problem with one of our staff laptops...
It's an HP 6720s, the teacher brought it to me and said the network wasn't working properly on it, so I plugged it into a point in my office and it worked perfectly. Teacher took it and left, next day came back and said it wasn't working again, plugged it in, worked perfectly.
So I took the laptop upstairs with me, to the staffroom where he'd be trying to use it.
To make sure everything was as it should be, I used one of the computers up there to ping our main server, sure enough not a single problem, every ping returns <1ms. I unplug the cable from the computer and plug it into the laptop and try and ping the same server and it seems to battle to respond, times out a few times, then one ping returns with a 200ms response, then a few more times outs, then 2 responses, then more timeouts.
I tried with a few cables in the staffroom, same problem, yet plug the PC thats normally up there in and everything is fine.
Now I would say its a faulty network port on the laptop, but then why does it work fine in my office?
2nd possible fault, in my office, the cable is about 2m long, then goes into a switch, in the staffroom, it's a good 60+ metres to the switch, is it possible the network card in the laptop is going and isn't able to push the signal down the cable?
Having said all this, it only occured to me today that I should have tested the wireless as well, just didn't occur to me at the time
Any suggestions regarding the cable would be greatly appreciated?
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14th September 2008, 07:48 PM #2
Possibly its using the wireless when in the staff room and its poor signal?
14th September 2008, 08:56 PM #3
Is the laptop gigabit (and the machine that worked in the staff room 100mb), gigabit uses all four pairs so it can show up cabling faults that aren't apparent when using 100mb.
Might be worth setting the laptop to 100mb instead of auto negotiate, this can also help if you get compatibility issues between switches and a particular piece of kit.
Last edited by K.C.Leblanc; 14th September 2008 at 08:58 PM.
14th September 2008, 09:16 PM #4
Have you 'upgraded' it to xp? We have these in a laptop trolley and I haven't got the network card to work with xp, you can flash the bios but then people have reported problems with the graphics. If I need to connect to our wired network I use a usb/rj45 connector. Also had issues with the wireless, the laptops don't like one of our buffalo access points, won't connect before logon! Apart from that they are lovely laptops
15th September 2008, 08:55 AM #5
- Rep Power
I saw a problem recenty when a Cisco switch was going tits up, it did it in a funny way though and started blocking certain MAC addresses only.
15th September 2008, 09:36 AM #6
We have a good number of these laptops and have found a similar issue (although not quite identical) but you may find this helps - we discovered a setting in the BIOS which had something to do with LAN/WLAN switching, which was disabled by default, but one or two of them arrived with this enabled. Turning this setting off solved our problems!
15th September 2008, 08:26 PM #7
Thanks for all your suggestions,
Some notes regarding the current situation:
kmount: Wireless was switched off at the time to make sure there were no conflicts, it was restarted, reconnected, unplugged, replugged etc...
K.C.Leblanc: The laptops are 100MB as are the switches
chrbb: They have all been 'upgraded' to XP :P However, they are running the newest bios, and the network card has been working perfectly for the last few months.
georgebush: Most of the switches are unmanaged Zyxel 100MB 24 Port switches, no MAC blocking, plus it does seem to let through a ping every so often.
sdc: Thanks for the suggestion, I will give it a go tomorrow and pray!
and finally, to make matters worse, another staff member's laptop has now begun doing the same thing.
Won't connect properly in the staff member's classroom, took the laptop to the network cabinet (30m down the corridor) and plugged it straight into the switch and it worked. I used a cable checker to check the cables from the switch to her classroom, seems perfect.
One thing that I did notice on this new problem laptop, the lights on the NIC, only the orange activity light is flashing, the green link light isn't on.
Unfortunatly I didn't think to check if this was the case when it was plugged directly into the switch.
As always, any help is greatly appreciated!
16th September 2008, 10:20 AM #8
Have you tried it with a different switch at the end of the problematic cables. I have seen individual ports on switches start to fail and perhaps the switches power output has dropped on some or all of the ports thereby reducing the effective range of cable. Also are your patch leads all the same grade as the building wiring ie cat5e, I have not seen it manifest as an issue but the different cable types could be causing signal jitter due to the different resistance values of the cables which the laptops are unable to compensate for.
16th September 2008, 07:28 PM #9
Thanks SYNACK, going to replace switches as soon as I get a chance...
I put a little 8 Port switch in the staff member's classroom and connected it to the wall box and to the laptop and all is working.
I'm beginning to suspect its the network port on the laptop, it seems to have a problem sending and receiveing over a certain length of cable.
Either that or its 2 different switches giving the same problem.
Having said that, there is now a 2nd laptop showing the same signs, which is connected to the same switch.
Is it possible the switch has surged or something and damaged the ports on the laptops?
Going to try replace the switch just to confirm it is infact, the laptops.
16th September 2008, 08:44 PM #10
I found that the HP wireless management SW was pants on these laptops and always use Windows to manage wireless.
Apologies if not a wireless issue.
17th September 2008, 11:57 AM #11
Thanks for the suggestion Tazz, but it's a wired issue
28th October 2008, 02:06 PM #12
Hey guys, just a follow up for those that are interested:
It turns out its the individual network ports on the notebooks.
I have no idea what's caused it or if there's a fix besides replacing the motherboard of the notebook.
Basically it will not communicate if the cable to the switch is over a certain length, not sure of the exact distance, but it seems to be over 30m?
Put a switch in at the end of the cable and use a 1m patch lead to connect the laptop and it works.
28th October 2008, 08:05 PM #13
We have loads of these and suffered the same problem, phoned up HP and its a known issue they sent me a firmware update which helped although i still had issues with a them disconnecting or erroring on some of the hp switches, updated firmware across all of these and problem solved.
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