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Last updated 16 May 2016

On 1 May 2016, the National Broadband Network announced that the new “Sky Muster™” satellite is operational. Why should anybody in Dereel care? It's slower and more expensive than fixed wireless from the local tower.

Unfortunately not every household in Dereel is able to receive signal from the tower with a roof-mounted antenna. It would be necessary to mount it on a mast, something that the NBN would rather not know about. But it is possible, and I think 90% of the “no reception” cases could be fixed this way. Yes, it costs money, but satellite is also more expensive. Read on.

The spanner in the works: latency

This section is relatively technical. It explains why satellite isn't as fast as other networks for a specified network speed. You can skip it if you like at move on to the next section.

The real issue with satellite—any conventional satellite, including Sky Muster—is that they are positioned in a geostationary orbit: they stay in the same position relative to the earth's surface. This greatly simplifies the system (otherwise you'd need multiple satellites and complicated antennas), but it requires positioning the satellite 36,000 km from the earth's surface. That's nearly 10% of the way to the moon. And every piece of data that goes across the network has to do this distance twice, up and down. The signals go at the speed of light, but that's only 300,000 km/s, so getting the data up and back again takes 240 ms (0.24 seconds). This time is called latency.

Conventional networks have latency too, but it's much less, in the order of 15 ms (0.015 s) for fixed wireless. In many cases, a program will need to send a message to a remote site and get a reply. With fixed wireless this takes 30 ms. With satellite it takes 480 ms. This still isn't that big a deal until you realize that loading a single web page can take up to 100 such exchanges. With fixed wireless, that would take 3 seconds. With satellite it could take 48 seconds.

The NBN fact sheet mentions latency, but doesn't say how bad it is:

How does latency affect the quality of certain applications?

As with all technologies, there are some specific characteristics and limitations. The main limitation of satellite services is the time that it takes the data to get to and from the satellites (latency). This means that some real time services, like online gaming, are affected by latency. Some people who work from home using Virtual Private Network (VPN) secured connections from their home to their office may also experience issues. Please contact your own help desk for further details.

This is glossing over the problem at best. You could be forgiven for considering it downright misleading. If you want to do online gaming, forget satellite. And there are other issues which I'll discuss below.

Jitter

Jitter is a problem in all networks. It refers to the differences in the time that individual data packets take to arrive. Some services, like VoIP (telephones) are particularly sensitive, and it can also be an issue with streaming video. Unlike latency, jitter is not inevitable. Here's an example on NBN fixed wireless, using the ping program (available on all computers):

$ ping www.google.com
64 bytes from 103.2.116.94: icmp_seq=11 ttl=59 time=18.532 ms
64 bytes from 103.2.116.94: icmp_seq=12 ttl=59 time=29.293 ms
64 bytes from 103.2.116.94: icmp_seq=13 ttl=59 time=87.325 ms
64 bytes from 103.2.116.94: icmp_seq=14 ttl=59 time=20.534 ms

The times at the end show the latency for individual packets. The first is 18 ms, the third is 87 ms, a difference of nearly 70 ms. This is not good, but bearable. I don't know how well SkyMuster™ will handle it, but my experience with other satellite technology showed that it was a very serious issue, with packet transfer times varying by up to a second.

Cost

Not all ISPs offer satellite, maybe because of the disadvantages: they don't want to have dissatisfied customers. One brave ISP who does is SkyMesh. But the prices are quite different. SkyMesh offers traffic for “off peak” (midnight to 7 am) and “on peak” (the rest of the day). Here a quick overview of the on-peak costs at 12 Mb/s:

Traffic (GB)       Fixed wireless       Satellite
5             39.95
6       29.95
30       39.95       49.95
50             114.95
60       49.95       199.95
120       59.95       (not available)
600       79.95       (not available)

The 60 GB on-peak is the maximum that you can get with satellite, and you'll see how quickly the prices rise. The reason for this is that the bandwidth for the whole satellite is severely limited, and they don't want people using up too much of it. From the fact sheet again:

Will there be a Fair Usage Policy in place for the new Sky Muster™ service?

Yes – the Sky Muster™ service will have a Fair Use Policy in place in order to help ensure fair access to the services over the new satellites – especially during peak-usage times. This Fair Use Policy applies between nbn and the internet service provider. The internet service provider will likely have a separate fair use policy which applies to households. Satellite capacity is a finite resource and nbn plans to work closely with internet service providers to help ensure they manage capacity properly, so that everyone has access to a great online experience

I use about 150 GB per month, and others use much more. Yes, you can get more off-peak, if you want to sit in front of a computer in the small hours of the morning, but that's not most people's choice.

What does this mean in practice? Three popular applications are video streaming, web browsing an telephones. I'll look at each of these.

Video streaming and download

Video over the net is not sensitive to latency, since the transfers are overlapped, though potentially jitter could be a problem. But it does transfer a lot of data. A single high-definition video can take 4 GB, which makes a significant dent into even a 60 GB plan. If you can arrange it so the the videos are downloaded in the middle of the night, you can get slightly more data, but it's still a problem.

Web browsing

Depending on the web site, satellite latency can really slow things down, or it can be barely noticeable. When I was using satellite I found that sites like http://www.smh.com.au/ were particularly bad, taking over a minute to load a page. Others, like Google, work pretty much the same as with fixed wireless.

Telephones (VoIP)

People tell me that you can use satellite for telephony. It never worked for me. There are two issues:

But it's better than mobile wireless broadband!

Not in my experience. Mobile broadband, at least round here, is slower, but the latency is much better, and overall speeds were better. But of course the data restrictions are even worse than for satellite.

So what's the alternative?

As mentioned above, most premises in Dereel that “can't get fixed wireless” really could get it if they mount the antenna on a mast. That costs money, of course. So does satellite. I don't know how much the installation would cost, but I'm guessing in the order of $200 to $1000, depending on how high the mast needs to be.

How long does it take to recoup the $1000? That depends on your data use. If you need the 60 GB plan above, you would pay $150 a month more than for fixed wireless. In that case you have saved the money within 7 months.

I'm currently investigating the possibility for a friend. If you're interested, contact me on 5346 1370 and we can discuss it.


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