Detect loss of wireless connection

GOAL : physicians in a hospital getting access to web-based JSP content through a Pocket PC browser(IE) and wireless connectivity. We already have the "normal-size" JSP pages for desktop computers and we'd like just to provide a reduced version of theses pages to browse on a PDA.
PROBLEM : Even with a well designed WLAN with good access point placement, you may experience connection loss. And it's a problem when browsing JSP pages : imagine submitting a form when you're suddenly offline : you'll get a 404 or something similar -> not serious.
QUESTION : If I port our application in the Personal Profile Xlet framework, Would it be possible to detect connection loss in an Xlet or somewhat... then it could set the rest of the app to work in a kind of degraded mode. How can we manage that ?

You could have a thread which is dedicated to managing the apparent connectivity. It connects to a well known location, if it cannot connect then you are assumed to be disconnected and the application should downgrade. The routines that handle networking should be able to fail gracefully and not generate exceptions which would terminate the program. As an example you can update your stocks whenever theres a connection but if there isn't one you can always show the value and the last time it was successfully retrieved.

Similar Messages

My ibook doesn't detect an existing wireless connection...please help

Hello,
just moved into a new house with wireless connection. all the other computers (PCs) can easily detect the wireless signal but my iBook doesn't. The airport is working properly since I can detect wireless connection in the university, cafes, trains etc...
the wireless router is a belkin.
Do you know if some special settings are required to be detect it or if there are some settings that can exclude my airport from the network?
please help me.... that's so frustrating!!!
federica

The Belkin router might have been set up to use MAC-address filtering. In that case, make sure to add the MAC-address of your Airport to the list of addresses allowed to access the router.
Also, if the wireless connection name (SSID) is hidden (= closed network) your iBook might not see the network untill you explicitly define the network as a new Airport network connection.

TC & MBP - complete loss of wireless connection and usage

I apologise in advance if this is a very long winded post! I've been an Apple fan for some 20 years now and it's only in the last three months that my love affair is starting to wane due to (what seems to me) poor hardware releases.
My setup:
1 x PowerBook G4 1.25Ghz with Edimax 802.11n PC Card
1 x MBP 2.4Ghz (purchased April 2008) with AirPort 802.11n
1 x Time Capsule 500Gb
1 x Airport Extreme Base Station Gigabit Ethernet edition
1 x Netgear DG384 v2 (wired only) modem router
1 x standard ADSL connection (8Mbps) from a UK ISP (and yes, 8Mb is about the norm for the UK! Though in reality, it means closer to 4Mb...)
The Netgear router is connected to the ADSL line and is set up as the DHCP server for the network. I have a Fixed IP address from my ISP. The Time Capsule is connected via ethernet to the Netgear router. The TC is set up in Bridge mode as the router serves DHCP. The TC is wall mounted via the excellent AirMount from H-Squared.
The TC has been through a myriad of configurations in an attempt to create a stable wireless environment since its purchase in April. Prior to my recent holiday (two weeks in Greece - hurrah!), the current configuration was solid for both Macs.
The config is: Bridge mode; 2.4Ghz N Only wireless; WPA2 secured; no MAC address access control restrictions (so pretty straightforward). The TC is running firmware 7.3.1. It is setup as "Create a Wireless Network"
Both Macs are running OS X 10.5.3 with all of the latest updates including AirPort Utility 5.3.2.
It took me about six weeks to hit upon this config for the TC having had many wireless drop outs, stalled connections, lost internet connections (ie. I could access the TC HDD but could not access the internet using the same wireless connection). So much frustration in the early days - I tried many of the solutions on this forum but to no avail until I hit upon the 2.4Ghz N Only route which seemed to be the answer to all my problems.
Prior to leaving on holiday, I unplugged all of the equipment in the room including the TC and the router. When I returned, I restarted everything in a logical sequence - router first (and waited for a connection), then the TC and then the Macs.
From this point on the problems have started. The PB G4 with the wireless card has a more or less stable connection. The wireless card connects immediately to the TC but then it takes approximately 30-60 seconds for an internet connection to work (so I see a lot of the Not connected to the internet messages in Safari). It seems to immediately get an IP address from the router via the TC but then the internet connection itself takes a while to come up.
The MPB on the other hand is a nightmare. Since returning from holiday I have not been able to get a workable wireless connection at all. In no particular order, the problems that the MBP exhibits are as follows (these can occur at the same time or individually):
i) only returns a self-assigned IP address; renewing the DHCP lease does not fix the problem
ii) does not see the network at all (although it will see others in the vicinity)
iii) cannot connect to the network - returns the Connection Timeout error or very occasionally the Password Incorrect error; I have tried connecting the network via the AirPort menu bar item, via Join another network... from the menu bar, via the Network selection menu in System Preferences > Network and even via Internet Connect - all with no success
iv) sometimes I am able to connect to the network but no IP address is received. Having checked the TC logs, it shows the same error occurring over and over again:
Jun 26 22:06:04 Severity:5 Associated with station 00:1e:c2:ba:78:6c
Jun 26 22:06:07 Severity:5 Deauthenticating with station 00:1e:c2:ba:78:6c (reserved 2).
Jun 26 22:06:07 Severity:5 Disassociated with station 00:1e:c2:ba:78:6c
The MBP connects but is immediately thrown off the network.
So to all intents and purposes, the wireless aspect of the MBP and the TC are completely useless.
When I use a wired (ethernet) connection to the TC everything is joyful. Instant IP address assignment, excellent connection speeds, no drop outs and so on. So as far as I can ascertain, the TC is working fine with the exception of the wireless/wireless security.
The AEBSn that is connected to the same network no longer appears in Airport Utility.
Having read through many posts here, I have tried many solutions including:
- downgrading the FW to 7.3; no difference at all
- turning off wireless security; no difference at all
- changing channels; I've tried 1, 6, 9, 11 and 13 with no difference at all
- changing the wireless mode; B/G, G only, N only all make no difference (I can't use 5Ghz N only as the PB G4 does not support this and I need both Macs wirelessly connected)
- rebooting the TC (both via Airport Utility and 'power off'); makes no difference
- reinstalled OS X 10.5.1 (via the install disks that came with the MBP) using the Archive & Install feature; then used the Combo updater to upgrade directly to 10.5.3; once again, no difference.
I have not yet done a hard reset as this has made no difference in the past but obviously I will try it.
In other words, HELP!
I am stymied. I have tried so many solutions offered on here and on the likes of MacFixIt and other Mac forums none of which have brought back my wireless connection for the MBP.
The MBP works very well with other wireless connection. For example, at work, we have a Linksys WRT54G wireless router connected to a BT leased line. I have not had a single connection issue for three months with this setup. Similarly, whilst on holiday, I used many different hot spots and had no issues with the wireless connection. All of this evidence leads me to suspect that the MBP is not the issue.
From what I can tell, the problem seems to be in the wireless security on the TC. It seems to prevent access by MBP (though not the PB G4 using a wireless card) but disabling security did not change the error messages shown in the log or the lack of connectivity.
It is a real shame that I cannot get a satisfactory working environment with the TC as the concept is great. The reality is, however, that it is unusable in its current condition and loathe as I am to try and return it or replace it, I am rapidly coming the conclusion I will have to.
Before I do, however, I am hoping that the genii who exist on these forums may be able to proffer some ideas or solutions that I haven't yet tried.
My sincere thanks will go to anyone who provides a solution for me. There may even be beer involved as a mark of gratitude!!
Thanks for reading and fingers crossed someone knows something special...

Smokerz: thanks for the reply and the advice. Not really in a position to set up a dual network at the moment due to the positioning of the TC and the AEBS but if I get an opportunity to try it I will.
I have temporarily given up with the TC as the router for the wireless network. I've installed a Vigor 2820n modem router (it's the only one I could find that has a Gigabit port - only one though) as well being a modem (ADSL) router. Thus far, everything seems fine - although I have had a couple of drop outs due (I think) the AirPort connection on the MBP. And interestingly, I've set up the TC as a "test" wireless network using the Vigor's internet connection and it's way more stable than with the Netgear router. So perhaps it's a combination of many factors - the poor Netgear router, the TC and the MBP AirPort connection - that was causing the issues.
I'll give 10.5.4 a go as well and see if that helps at all.
Thanks to all who read the question - if anyone else has thoughts I'd be delighted to hear them.

Loss of wireless connection

I've completely lost my wireless connection to my home hub although I can connect through an ethernet cable. I can connect to a wi fi hotspot. This has happened before and phoning the helpline has got it working again. This time I was told I need a new router and would get one if I renewed my contract. As a 10 yr customer I wasn't happy! If I refresh the network list, my home hub is there but the connect failure message mentions TCP/IP is not configured although settings of my adapter say it is. I've tried another router but exactly the same thing happens. This is also the scenario on the stepsons macbook. Any thoughts?

There is some help on this page.
Wireless connection problems
There are some useful help pages here, for BT Broadband customers only, on my personal website.
BT Broadband customers - help with broadband, WiFi, networking, e-mail and phones.

Loss of wireless connection with 350n

I am having a terrible time with loss of connection with my 350 N wireless router. The router itself is on top of a bookshelf less than 50 feet away from both of my wireless desktops, and faces straight down the hallway that both rooms the computers are in open from. Often when I start up my computer it refuses to acknowledge that there is a wireless network present in the house and the only way I can make it detect it is if I powercyle the router--which is a pain. Even sitting directly next to the router it will never recognize better than 85% signal strength. And when I load (not play, just initiate loading) download-heavy content such as streaming video or an MMORPG program the connection will often drop and then reconnect seconds later. Upon performing a speed test it unfailingly indicates that my upstream is twice as fast as my downstream, which reads at only around 1165 Mbps--which is absurd as my modem is provisioned for and often surpasses 16000Mbps. What on earth is going on and what can I do to overcome it? I'm getting desperate here.

I have fixed my problem by upgrading the router firmware to version 1.03.7 from version 1.03.5.
The issue I had upgrading the router was it would fail at about 80% when using the router to do the upgrade soooooo, this is how I did it ( stolen from another thread )
Be warned! If you do the below and you have custom setting on the router you need to write those setting down first!!!!!!
1. Download tftp.exe using this link (ftp://ftp.linksys.com/pub/network/tftp.exe)
2. Download the new firmware (version 1.03.7) at Linksys download site
3. Reset your router by pushing and holding the reset button in the rear for 30sec
4. Configure a static IP address (192.168.1.50 with Subnet Mask 255.255.255.0) on YOUR PC
5. Connect a network cable from your PC to your router
6. Test that your PC is talking to the router by openning a DOS window and type "ping 192.168.1.1" (without the paranthesis) and you should get 3 replies.
7. Double click on the tftp.exe
8. Type in the IP Address for the Server: 192.168.1.1
9. Password is "password" (WITHOUT the paranthesis)
10. For the BIN file, click on the square-button and browse to the BIN file that you've downloaded from the LinkSys Site (WRT350N_1.03.7_US_code.bin)
11. Click on Upgrade
12. After the upgrade is successful, perform the reset, again. IMPORTANT!!!! PUSH AND HOLD THE RESET BUTTON FOR 30sec then let go.
13. POWER light should be blinking during boot up then stay SOLID
14. Now, change YOUR PC IP seeting back to what they were before you started this process.
15. Start InternetExploder and surf the net
16. GOODLUCK!!!
As soon as I did this, my laptop wireless started working 100% and right away.

Loss of Wireless Connectivity

Hello Everyone,
I am having a major problem with my wireless network. At random intervals, I notice my wireless network speed (54mbps) slowly decrease from 54 -> 48 -> down to -> 4 -> 2 -> 1 -> dies. My wireless router then goes off for anywhere between 10s to 10 minutes, or sometimes it can even be down for 45 minutes.
I've encountered this ever since I moved my PC from across my room, though I believe it happened rarely before hand as well. Ive since tried using programs to determine the best connection (which Ive finally achieved). Also due to the building, I cannot run a wired line to my computer. My computer sits about 25-30 feet away from the router, almost a 45 degree angle above it (2nd floor, router access point is on the 1st).
Another note: Its not just my personal computer that loses wireless, the entire network dies at the same time. Though, the WIRED network that is connected to the router receives no interuption. I have exchange students that board at my house from time to time, along with the other main computer that resides in the room with the router, and neither receive connection hiccups or loss of network bandwidth. Also during this time my Wireless PCI card in my tower can still detect other networks (though very weak due to range)
As a thought, my router was about 2 years old, so I recently upgraded it from WRT54G to a WRT300N. The issue is just as frequent.
As for specifics:
Network:
Old Router: WRT54G (2 1/2 years old)
New Router: WRT300N
-- Router runs WEP encrypt, Ive recently turned off MAC filtering, tested both Channel 1 and Channel 10 (6 is overloaded with 2-3 other routers in the area).
Wiress PCI Card: WMP54GS (90% sure I have the Speedbooster Version)
-- My PCI card has a 7db antenna attached on a 1.5m chord.
Cable Modem (About 8 years old, unfortunately)
Computer Setup
Windows XP Pro 32bit
ZoneAlarm Firewall / AVG Virus Scanner
Intel Quadcore @ 2.4ghz / 2gb Ram @1066 / Dual Harddrives
Side Note: I live about 100-200 metres away from a Canadian Forces Naval Base. I hadn't had any major connection issues prior to moving my computer 16 feet over to the other corner of my room, but unsure if military base could provide wireless interuptions as Im describing.
The only other thing I can think of at this time is range, as Ive gotten my connection down to a 30 based Signal to Noise ratio (Used Netstumbler to determine)
Also plan to upgrade my PCI card to N shortly, though depending.
Any thoughts or help would be greatly appreciated! Thank you!
-David Bright

I cannot confirm that other Wireless routers in my area share this same issue. I haven't tried to update firmware yet, as from the few I had talked to you generally don't want to touch something like that until a last resort.
I use a program called "Netstumbler" to detect other networks around me. As best as I can tell, when my router disappears off the grid, a lot of other routers do as well. I've used Channel 1 on G frequencies because the average number is as follows:
Channels:
1 - 1 person (me)
6 - 4 people (unknown)
11 - 1 person (close neighbour).
As to which neighbours are using wirless routers, Im unsure. About 30 meters away from my router, as mine unfortunately is placed agaisnt the house wall, is a complex that houses about 20-25 families. My computer also shares the same wall, but a floor above (like stated) for connectivity.
As for firmware, I believe I'll have a look into which Im running and hopefully update. I think it might not hurt even looking into an update for my PCI card as well.
Anymore help regarding this issue is appreciated. Thank you

My mac is causing loss of wireless connectivity on pc's

Okay so i have a new macbook and the airport card appears to be working fine. my friend has a new sony vaio. I can connect to their wireless network just fine, but for some reason, when i connect, even if it turn air port off, the vaio will not connect to the wireless network. It recognizes the network and shows full signal strength, but reports that there is limited connectivity and will not browse the internet. I have tried a lot of things such as restarting the viao, disconnecting and reconnecting to the network, but the only thing that seems to work is to unplug the wireless router and then plug everything back in. Does anyone know of a reason air port would cause this type of interference? Thank you so much!

I cannot confirm that other Wireless routers in my area share this same issue. I haven't tried to update firmware yet, as from the few I had talked to you generally don't want to touch something like that until a last resort.
I use a program called "Netstumbler" to detect other networks around me. As best as I can tell, when my router disappears off the grid, a lot of other routers do as well. I've used Channel 1 on G frequencies because the average number is as follows:
Channels:
1 - 1 person (me)
6 - 4 people (unknown)
11 - 1 person (close neighbour).
As to which neighbours are using wirless routers, Im unsure. About 30 meters away from my router, as mine unfortunately is placed agaisnt the house wall, is a complex that houses about 20-25 families. My computer also shares the same wall, but a floor above (like stated) for connectivity.
As for firmware, I believe I'll have a look into which Im running and hopefully update. I think it might not hurt even looking into an update for my PCI card as well.
Anymore help regarding this issue is appreciated. Thank you

Sudden slowness and loss of wireless connection to PC

I've used my Dell laptop on my Airport Extreme wireless network without problem for two years. Yesterday, after installing an HP 8500 printer on the network, my PC became extraordinarily slow on the network, and kept losing its connection. I haven't been able to get it fixed. I've reinstalled the airport extreme, I've reset the cable modem and have turned my firewall off, but nothing has worked. I also uninstalled the printer, but that didn't help either. Any ideas for other things I can try? The imac and iphones connected to this network are still functioning fine, as is the printer, which I've now re-installed. It's just my Dell laptop that is not. Oh, btw, I took the laptop to a wireless hotspot this afternoon, and had no problem connecting to that network.

Update: Reverted to firmware version 7.4.2 and the problem was instantly solved. Hallelujah!

Update to 10.5.2 caused loss of wireless connectivity

After updating from 10.5.1 to 10.5.2 I couldn't connect to Network (wireless). Router function checked out ok with ISP. (I could get online wirelessly with my PDA.) I could get connectivity with my MBP via ethernet cable. I also couldn't connect wirelessly to my printer (which I could do before). Spent a lot of time with AppleCare tech. but didn't solve anything. Wound up reloading OS and restoring w/Time Machine. I'm back to v.10.5, and all works well. I'm reluctant to upgrade to anything further at the moment (maybe to 10.5.1...?). I'm concerned that I'll wind up with the same problem if I go up to 10.5.2. Any thoughts where I should go from here?

I'm "replying" to my own message because I need to modify it! With v.10.5 that I wound up with, I lost functionality of iTunes, plus a couple of other apps. Feeling masochistic, I then updated (again!) to 10.5.2. The various functions are back working fine, but AirPort cannot connect. I therefore connected my MBP to the router with an ethernet cable. Everything works OK, but it would sure be nice to function wirelessly like I did before the update! Any suggestions would be appreciated. BTW, on my system, I have Parallels and WinXP, but I haven't used it in several weeks; might there be some sort of conflict there, even if I'm not using Parallels?
nhuser

Detect loss of socket connection using java.nio.channels.Selector

I'm using the nio package to write a "proxy" type application, so I have a ServerSocketChannel listening for incoming connections from a client and then create a SocketChannel to connect to a server. Both SocketChannels are registered to the same Selector for OP_READ requests.
All works fine, until either the client or server drops the connection. How can I detect this has happened, so my proxy app can drop the other end of the connection ?
The Selector.select() method is not triggered by this event. I have tried using Selector.select(timeout) and then checking the status of each channel, but they still show isConnected()=true.
Thanks,
Phil Blake

Please don't cross post.
http://forum.java.sun.com/thread.jsp?thread=184411&forum=4&message=587874

Firefox won't detect coffee shop wireless internet connection, but explorer will, automatically

Firefox won't detect coffee shop wireless internet connection, but explorer will, automatically

that's fine, thank you
but if it doesn't connect
what's the alternative procedure
what do I do

What are possible causes for frequent loss of wireless mouse connectivity other than the batteries ?

What are possible causes for frequent loss of wireless mouse connectivity other than the batteries ?

Wi-Fi or another interference source. Try turning off the Wi-Fi and see if the problems continue. If that solves the problem, see if you can set your Wi-Fi to run in the 5 GHz range.
Keyboard/Mouse – Troubleshooting Wireless
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T61: no detection of wireless connection

Dear Experts,
I am a 0% technical person. I am using my T61 bought in year 2007 after a few months. And for some reason it is not detecting any wireless connection even though I am able to detect the wireless connection on all my other devices.
On the wireless radio page it shows 802.11 and i have ensured that this is on and the wireless symbol as seen below my laptop screen is lighted.
Please advise me. In case you require any additional information, please let me know. You may also have to provide me instruction on where will I find the information requested.
Also, my laptop's key configuration is as below:
OS: Windows Vista Home Premium
Processor: Intel Core 2 Duo CPU T7300 @2.00GHz
RAM of 2GB
System time: 32-bit
Do you think it is a good idea to upgrade the OS? If yes, please also advise on the steps to upgrade the OS.
Many thanks in advance.
Best regards,
Bakul

I am just piling on to this last message-I don't have a successful connection. I was able to get a green light on the airport express unit by first doing a wired set up to my verizon fios modem- as I did setting up with wireless printers. But the airport utility does not find it. It did find it once - and the itunes speaker icon lit up - but then it couldn't find the boze and - even after complete restart - it can't find the AE. I suspected it was a problem with the WEP encryption on my FIOS modem - but since the light is green I'm assuming it has the correct network settings. It's just not recognized by my Imac. I just want to install it on my existing network to output itunes to the Boze speakers in another part of the house. Note - I've been configuring this right next to the modem and wireless distance is not an issue.

Satelite M300-D4316 - wireless network detected but can't connect

Previously I could use wireless LAN on my laptop but last week since I registered a bluetooth connection, wireless connection doesn't function anymore.
It can still detect wireless network around me; I fail every time when I try to connect, & it asks me to diagnose the problem & says something like 'signal is too weak'.
I'm pretty sure that it's not the problem of the wireless service- all my friends can connect to it!
What should I do?

Maybe the Wireless LAN was toggled off?
Try pressing Fn+F8 to toggle the Wireless Devices.
Also ensure the Wireless Switch is turned on at the front/side of the notebook.

Wireless connection loss on my imac and not on my macbook pro

i have an imac with software 10,4,11 and since a certain time every time my imac go in sleep, re-waking up he loses wireless connection for a few seconds so internet blocks, i hav also a macbook pro, same connection same software and no problem at all. who can help me how to solve my wireless connection problem

If it's an encrypted connection, One thing that can work, try this, please ignore the exact symptoms and connection and Hardware types, it's worked for many others than the stated...
http://docs.info.apple.com/article.html?artnum=304482

Detect loss of wireless connection

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