måndag 25 juli 2005

Wireless Wrestling, Part II

Disappointed by the Netgear WGT624, I thought that I would try my luck with D-Link wireless products. So about a week and a half ago, I got a D-Link DI-624+ router and a DWL-G122 USB adapter.





The installation procedure is very similar to that of the Netgear products I previously tried. The router is configured using a browser (the D-Link interface supports Firefox, like that of Netgear, I’m pleased to report) and the adapter uses custom software included on CD.
This router operates in 54 Mbps rather than 104 Mbps. In practice I get 14.4 Mbps when performing a wireless FTP download to my laptop from the PC. Watching a streamed movie works without a hitch. My PC and server, both connected via cable, communicate with each other in 85.6 MBps out of a theoretical 100 MBps. That is more than sufficient for my needs.
The web interface used for the configuration of this router feels somewhat cluttered and confusing. The placement of sub-categories within five main categories seems largely arbitrary. Nonetheless the basic features are all present. A dynamic DNS update for the www.dyndns.org service is present, but I had to quickly disable it as it did not pay attention to whether the host already accurately resolved to the correct address — causing DynDNS to ban the host.
Having been in the company of this router for some time now, I have found it to be less error-prone than the Netgear. However, this one, too, has the very annoying habit of rebooting randomly. Sometimes it happens several times per day. Sometimes the interval between reboots is many hours, other times just an hour. In some cases it forgets the system clock as well, adding to the annoyance factor.
D-Link Support first suggested to upgrade to the latest firmware (which was already present on purchase), and then wanted to replace the unit. Fearing bugs or design flags given widespread reports about reboots by other owners of this model, I decided to evade the potentially lengthy warranty route and just return it to the store in favour of another brand.

fredag 15 juli 2005

Wireless Wrestling

I wanted to free my new laptop from the constraints of cables, and invested in a Netgear WGT624 router and WG111T USB adapter combination.





The install was fairly quick and painless. I connected my Windows XP desktop PC and my Linux server using the Ethernet ports, and plugged the adapter into my laptop. The router interface is accessed using a standard web browser, and I was happy to note that Firefox worked well. The adapter requires custom software to be installed. The router is fairly full featured, supporting encryption standards WEP and WPA-PSK and all the usual features like port forwarding. The router did not appear to limit my external bandwidth, which is 10 Mbps / s. In 108 Mbps mode, I measured at most 20.8 Mbps / s during a large wireless FTP transfer.
Having been running it for several days, I have discovered some problems however.
  • Seemingly at random, it drops all of the connections on both wired and wireless ports. When this happens, the interface reveals an uptime on all ports consistent with the timing of the dropped connections. The obvious conclusion is that it reboots itself.
  • Sometimes wireless latency increases substantially. At worst it takes several seconds before a key press is registered on a telnet connection. Out of several sent ping packages, some or all are lost. When I disabled 108 Mbps mode and returned to the standards-compliant 54 Mbps mode, this problem appeared to disappear however.
  • Sometimes during moments of increased wireless network activity, such as when copying files between one of my cable-connected computers and my laptop, the wireless connection is suddenly lost. Netgear’s software still indicates excellent signal strengh, and the cable-connected computers remain flawlessly connected. In this mode, I found that I am able to restore wireless connectivity by selecting Repair on the connection in Windows. However, manually executing the steps that are supposed to take place during the repair operation does not appear to solve the problem so it is difficult to pin down exactly what is going on.
  • When testing wireless bandwidth throughput using TPTEST, an open source tool released by the
    Swedish Consumer Protection Agency, the router usually locks up completely and requires a manual reboot (unplugging the power adapter and then plugging it back in).




After extensive searches in various on-line forums, I noted that lost connections and reboots appear to be common problems with this router model. Some believe that the problems can be explained in part by over-heating, and have devised clever though intrusive solutions. Some note that their power adapters deliver substantially more than the labelled 12 V, and switching to other adapters sometimes resolved the problems. Curious, I measured the voltage from my own adapter and got 16.5 V. I downloaded the latest beta firmware and believe that it may have alleviated some of the problems, but the router continued to lock up while running TPTEST — a disturbing sign that not all is well yet. In addition, it continues to reboot on random occasions.
Netgear Support offered some standard advice but could not resolve the problem. I returned it to the store which offered to take it back and refund me. I accepted.