G.Fast over Coax

There is yet another new technology available to carriers – G.Fast over coaxial cable. Early trials of the technology show it works better than G.Fast over telephone copper.

Calix recently did a test of the new coaxial technology and was able to deliver 500+ Mbps for up to 2,000 feet. This is far better than current G.Fast technology over copper which can handle similar data speeds up to about 800 feet. But telephone G.Fast is improving and Calix just demonstrated a telephone copper G.Fast that can deliver 1 Gbps for about 750 feet.

But achieving the kinds of speeds demonstrated by Calix requires a high-quality telephone copper network. We all know that the existing telephone and coaxial networks in existing buildings are usually anything but pristine. Many existing coaxial cables in places like apartment buildings have been cut and re-spliced numerous times over the years, which will significantly degrade G.Fast performance.

This new technology is definitely going to work best in niche applications – and there may be situations where it’s the clearly best technology for the price. There are a surprising number of coaxial networks in place in homes, apartment buildings, schools, factories and older office buildings that might be good candidates for the technology.

A number of telcos like CenturyLink and AT&T are starting to use G.Fast over telephone copper to distribute broadband to apartment buildings. Since as the incumbent telephone company they can make sure that these networks are available to them. But there might be many apartment buildings where the existing coaxial network could be used instead. The ability to go up to 2,000 feet could make a big difference in larger apartment buildings.

Another potential use would be in schools. However, with the expanding demand for broadband in classrooms one has to wonder if 500 Mbps is enough bandwidth to serve and share among a typical string of classrooms – each with their own heavy broadband demand.

There are also a lot of places that have coaxial networks that you might not think about. For example, coaxial wiring was the historic wiring of choice for the early versions of video surveillance cameras in factories and other large businesses. It would not be hard to add WiFi modems to this kind of network. There are tons of older hotels with end-to-end coaxial networks. Any older office buildings is likely to have coaxial wiring throughout.

But there is one drawback for the technology in that the coaxial network can’t be carrying a cable TV signal at the same time. The coaxial G.Fast operates at the same frequencies as a significant chunk of a traditional DOCSIS cable network. To use the technology in a place like an apartment would mean that the coaxial wiring can no longer be used for cable TV delivery. Or it means converting the cable TV signal to IPTV to travel over the G.Fast. (but that wouldn’t leave much bandwidth for broadband.) But still, there are probably many unused coaxial wiring networks and the technology could use them with very little required rewiring.

It’s more likely that the coaxial G.Fast could coexist with existing applications in places like factories. Those networks typically use MoCA to feed the video cameras, at frequencies that are higher than DOCSIS cable networks.

But my guess is that the interference issue will be a big one for many potential applications. Most apartments and schools are going to still be using their networks to deliver traditional video. And many other coaxial networks will have been so chopped up and re-spliced over time to present a real challenge for the technology.

But this is one more technology to put into the toolbox, particularly for companies that bring broadband to a lot of older buildings. There are probably many cases where this could be the most cost effective solution.

An Industry of Hype?

Bandwidth_thickAlmost every day I see somebody in this industry making a claim that makes wince a little bit. It might be vendors talking about gigabit speeds. It may be service providers talking about gigabit cities. And to some extent I get it. It’s a world driven by marketing and everybody competes first with hype. Those in the know quickly figure out the truth, but I guess what bothers me is that others don’t.

Let’s start with the equipment vendors. The country is pushing hard to get gigabit bandwidth into our schools. And since schools are already wired with coaxial cable, this led me to look at the technologies that are in use today that can deliver bandwidth over existing cable in schools. After all, what good is bringing a gigabit to a school if you can’t actually get it to the classroom? The various technologies including HPNA, MOCA and HomePlug all claim gigabit-capable speeds. Additionally, the new WiFi standard of 802.11ac promises gigabit and above speeds. Another upcoming technology is G.Fast that is promising to do gigabit speeds on copper.

But none of these technologies actually delivers a gigabit at the application layer, which is the usable speed of bandwidth that is available to an end user. Some of these technologies do provide a gigabit of theoretical data at the transport layer, but after accounting for the various overheads, noise, interference and other factors, the actual bandwidth is much slower than advertised. Additionally, the speeds they tout are the total bandwidth of the technology and those speeds need to be divided into an upstream and downstream component, further diluting the bandwidth.

At best of these various technologies today deliver maybe a total of 400 Mbps in total bandwidth, and a few of them are quite a bit slower than that. So it turns out that these gigabit technologies are not really a gigabit, or even half a gigabit. But a non-engineer would not know this by looking at how they are advertised.

We have the same thing going on by service providers. For years broadband providers have sold ‘up-to’ data speeds that they were never able to achieve. There is still a lot of that going on, particularly in smaller markets where the advertisements talk about the speeds in nearby urban areas and are far in excess of what can actually be achieved in small towns.

But the one that really gets me is the term gigabit cities. When I hear gigabit cities I picture a place that is building a network that will make a gigabit data product available to every home and business in the community. And there are almost no cities like that.

People think Google is bringing gigabit everywhere, but they aren’t. First, they only go to neighborhoods that guarantee a certain penetration rate for Google. And once there they don’t serve any apartment complexes or businesses. Google is basically cherry-picking residents willing to pay $70 per month for data. While laudable (and I wish I could get it), Google is not building gigabit cities.

There seems to be other cities announcing themselves as gigabit cities almost weekly. Some of them offer gigabit speeds to residents, but at very high prices as much as $250 per month. Most of these cities only supply gigabit speeds to schools and a handful of large businesses. Again, very laudable and I am happy to see anybody invest in fiber. But gigabit to the schools and factories does not make a gigabit city. It just makes fast schools and factories.

There are a small handful of places that really are gigabit communities. There are some small telcos, municipalities and cooperatives that are offering gigabit to everybody in their footprint. But this is really rare and for the most part these are small communities. Interestingly, the folks that actually do it don’t tout themselves and just quietly deliver fast speeds to customers. I’m starting to think that the ones who yell loudest are the least likely to actually be doing it. I hope somebody can prove me wrong about this.