This is an attachment to my diary entry for 1 July 2011, where I rant about the actions of Australia's “National” Broadband Network, who seem to think that satellite Internet is a “metro-comparable broadband service”. This is not the case, and it can never be the case. Satellites can never compete with other services in terms of latency. It seems unlikely that they can match ADSL or fibre in terms of data cost, though potentially a subsidy would help there. But none has been offered. And reliability is a serious issue that I fear will also not be addressed.

• Latency kills. This is a question of absolute physical constraints. The satellites are in geostationary orbit 36,000 km above the surface of the earth. Radio waves can't exceed the speed of light. A ping round trip thus needs to cover the 36,000 km four times: Up, down, back up and back down again, a total of 144,000 km. At 300,000 km/s, that's a time of 480 ms (0.48 seconds), and there's no way to reduce it.

  Not that it makes much difference. My real ping times with IPStar were seldom less than 800 ms, and sometimes as high as 1500 ms (1.5 seconds). The reasons for this were presumably elsewhere in the network. By contrast, typical latencies in the ADSL space are 10 to 20 ms.

  High latency may not seem a big deal: yes, you can really get relatively high speeds out of satellite. I've had my highest ever download speeds via satellite, up to 500 kB/s. If you just want a satellite connection for downloading pornography, you might think that this is OK. But read on.

  The real issue with latency is in setting up TCP connections, which a typical web site does multiple times for a single page. Each of them require a three-way handshake. That slows things down even for normal connections, but it's disastrous for satellite. For example, the home page http://www.nbnco.com.au/, the rather strange URL that the “National Broadband Network” has chosen, requires no less than 52 TCP connections to display. If they were done sequentially, it would take about 3 minutes to display that page via satellite. I'd be interested in feedback from satellite users about how long it really takes.

  Latency doesn't completely kill VoIP, though it makes it very difficult. When speaking on the phone, people are used to taking a certain small amount of silence—well under a second—as meaning that the other person has stopped speaking. But with nearly 1 second delay, people continually interrupt each other. Even with 3G latency, about 100 ms, it's a problem.

  That's not even the main problem with VoIP over satellite, though. The real issue is jitter, the difference in the latency. That, too, can go up to several hundred milliseconds, and it completely destroys the sound. I tried a couple of times when using satellite, and gave up. It was completely useless.

• Reliability is an issue which could (and should) be addressed. Given the mentality of the people running the service, though, I don't see it happening.

• Traffic is another issue. SkyMesh have put up their pricing for the NBN scheme. The maximum traffic you can get per month is a total of 20 GB (14 GB in the morning, 6 GB in the afternoon), and it costs $100. For that price, Internode offers 600 GB, and that at ADSL2+ speeds. That's a factor of 30 to 1, and a reason why you shouldn't use satellite to download pornography.