Detecting ISP Throttling


ISPs have recently become very aggressive towards their customers. They’ve been blocking or altering traffic to prevent you from using specific programs or protocols. Google’s Senior Policy Director recently stated that they’re developing tools to allow people to detect ISP interference. A couple other groups have been building tools as well: The Network Neutrality Squad just released the second beta of their Network Measurement Agent. The tool currently detects spoofed packets by monitoring the round trip time of the connection; early reset packets will have lower than average RTT. If you want to go more in depth, the EFF has published a guide for using Wireshark to do the detection. We’ve even heard rumors of people building tools to tunnel a session inside of one that looks completely different.

[photo: nrkbeta]

Notacon 2008: Last-mile Wireless


[Mark Doner] presented on how the WISP he works for near Toledo is set up. His most important point was that 802.11 is garbage when it comes to the type of installations WISPs do. 802.11 expects the clients to adjust based on the traffic from other clients, but when all your clients are directional they won’t see each other. Mark uses Motorola’s Canopy equipment, but he also mentioned Trango and Redline as other vendors. The radios operate in the 5.7GHz band which doesn’t have any power restrictions so they can use refurbished Dish Network dishes when they’re doing long shots. For customers that are nearly at the edge of service, they have 900MHz equipment as well. Heavy fog and freezing rain have proven to be the only weather that really affects the service. For back-haul between their towers they use Dragonwave equipment. Each of the radios costs ~$350 and features GPS to determine distance and maintain sync with the AP. It was interesting to see how a good WISP operates as opposed to the flakey ones we’ve had to deal with in the past.