Google Fiber - Less Filling (cost) Tastes Great (more bandwidth)?

There is much excitement in the news and on the Web about the Google Fiber rollout planned for Kansas City. With the promise of 1Gbps to the home at a good price point, this sounds great. There have been posts that talk about whether Google understands what they are getting themselves into:

http://techcrunch.com/2012/07/28/google-fiber-devils-advocate-bitches/

The bottom line is that the installation of physical facilities into people’s homes means Google now has to take responsibility for prompt repair that ranges from minor problems, a failed home unit (a GPON ONT?) or major damaged caused by acts of nature.

However, my bent is a bit different.  First, Verizon, which uses GPON technology for their FiOS service, could provide a “1Gbps” service.  But, let’s take a bit of a look at the reality here.  Any service, virtually no matter the technology, has aggregation points.  With GPON technology the concentration point is at the Optical Line Termination equipment (OLT).  Each tradition GPON port provides 2.4Gbps downstream and 1.2Gbps upstream that supports the Optical Network Terminals (ONTs) at the customer location.  Even if you provide a service template that enables 1Gbps peak to each customer, there are generally 32 to 64 customers per GPON segment.  Also at the OLT is the amount of uplink bandwidth from the OLT to the Internet.  In general there are one to four 10Gbps uplink connection.  So, in the best case there are 40Gbps to spread over the hundreds of customers connected to the OLT.  Moving to DWDM-GPON or 10G-GPON reduces contention on the segment to a customer, but there are still limitations from the OLT to Internet.

Of course, you would say that people only need 1Gbps for a very short time so there is great packet statistical gain on the system.  And of course you would be correct.  So, let’s look at the sustained traffic that could be demanded by a customer.  Unless the typical consumer has a video production company putting together 1080p contribution quality video for Hollywood, most likely the home’s bandwidth is dominated by video consumption.  Let’s say the home has four HD TVs, each with the ability record two streams at each TV.  In addition, there are three mobile devices that will watch video at the same time.

So, the math works out as:

4 HD TVs x 3 HD Stream + 3 Mobile HD x 1 HD Stream = 15 HD Streams

Wikipedia has listed bandwidths required by the popular streaming services.  The largest bandwidth, the 1920x1080 video from Sony is 8Mbps.  For our purposes, let’s round-up to 10Mbps.  With that in mind, the sustained bandwidth from a customer would be:

15 HD Streams x 10Mbps = 150Mbps

This current peak fantasy is approximately an order of magnitude less than 1Gbps.

The math from the OLT to the Internet is interesting as well.  Assuming that you only do 20 customers per GPON segment (so that they can each get their 150Mbps for their HD streams) and with the typical 40Gbps uplink on the OLT, you get a maximum of 20x40 = 800 customers per OLT.  And of course, you have to find a way to get the 40Gbps from the Internet.  A Content Delivery System located close to the OLT helps dramatically, but again drives-up cost.  Google has implemented their own fiber-based nationwide backbone network, is this something they plan on leveraging to become a new Tier 1 ISP?

The bottom line is that for the vast numbers of consumers, the practical limit of consumption has nothing to do with the limitation of the access system from the home and more to do with the limitation (which of course will change, although 15 HD streams seems pretty generous at the moment) of the ability to consume product.

This becomes a marketing game as there is no significant near-term and probably medium-term benefit for a 1Gbps connection, or anything above around 100Mbps.  Will local providers start removing the limits (where they can, for example if they use GPON or DOCSIS 3.0) on local access, moving the service bottleneck elsewhere? 

So, I don't sound like a Luddite, there are likely to be future new applications that may drive change in my analysis and new devices that consume even more.

Of course, if you can only get DSL services a several Mbps, it's time to call Google (is that possible) and petition for your community to go Google Fiber.