Friday, February 26, 2016

A Broadband User Average Throughput is 150 kbps, not 25 Mbps

The following are all clipped excerpts driving the point that a good broadband experience averages only 150 kbps...the contended data rate...not the headline "advertised rate of 25 Mbps.

Each satellite beam has a different capacity in terms of maximum bandwidth, which is split across all end-users in the beam, and cannot be changed. The highest-capacity beam can serve ~15,000 premises, while the 20 lowest- capacity beams can serve an average of ~700 premises each.
   The Corporate Plan 2012–15 provided a budget of $3.5 billion capex to 2021 to build 1,400 fixed wireless towers, launch 2 satellites and install end-user premises equipment. The plan anticipated a 22–25 percent take-up rate and predicted connections to ~230,000 premises (with some additional capacity available)
   The Review believes that take-up will likely be 2–3 times higher and that between 440,000–620,000 connections will be required across the footprint. The capacity constraints of the satellites and the coverage restrictions of fixed wireless towers mean that at the proposed specifications, the Corporate Plan 2012–15 would not be able to provide all the necessary infrastructure to meet the Government's objectives. While fixed wireless towers can accommodate some of the higher demand, at the higher take-up expected, ~200,000 premises would not be able to be served by NBN Co.
   All scenarios assume that NBN Co implements a standard product construct with a network capacity allocation per end-user of 150kbps on satellite when the network capacity is contended, given the limited capacity on the satellite. Note that network capacity allocation refers to the average of all data downloaded across all end-users in a satellite beam. It is quite different to peak speed and is consistent with a headline peak speed of 25Mbps. The proposed product construct is based on latest current thinking and on performance estimates provided by the satellite manufacturer.

There is a large variation in the products and retail plans offered by satellite service providers around the world. For example, Exede in the US offer a '12/3Mbps' product with a 10GB cap for $50 US Dollars per month. This product effectively translates to a cost of ~$5AUD/GB/month. Hughes in Canada offers a standard '5/1Mbps' product with a 10GB monthly usage cap for $40 Canadian Dollars, which translates to ~$4AUD/GB/month. Higher cost plans include Tooway in the UK who sell a 2GB cap product for 20 GBP per month (~$18AUD/GB/month), VSAT in the US who sell a 16GB cap product for $359US Dollars per month (~$24AUD/GB/month) and Ground Control in the US who sell a 3GB cap product for $400US Dollars per month (~$143AUD/GB/month).
The Review proposes that NBN Co create an initial standard satellite product based on a busy hour throughput (i.e. allocated capacity) of 150kbps per end-user, priced at Uniform National Wholesale Price (UNWP) rates. Upgrade options may then be provided beyond that. As the LTSS platform cannot be field trialled until the first satellite is deployed, NBN Co may need to revise the marketed performance levels and network capacity allocation per end-user to match the reality of what is delivered. Further, NBN Co has an unbudgeted contingency plan to expand the footprint of the terrestrial technical solutions.

The Review proposes that NBN Co:
   Proposed action 5.1: Create a standard satellite product with a specific network capacity allocation per end-user (150kbps) with upgrade options possible, and ensure that the expectations of end-users are clearly and effectively managed.
At a given take-up rate per technology (e.g. ~ 65 percent for satellite, ~ 55 percent for fixed wireless), and assuming a consistent product dimensioning on the satellite (e.g. 200kbps network capacity allocation per end-user), and a given number of base stations, the model assesses how many premises are not served by any technology, and in which beams these premises are located.
   If only the 1,400 base stations assumed in the Corporate Plan 2012–15 are built, ~200,000 premises will be left unserved across 31 beams (assuming no FTTN build). Of these beams, 18 are more than 50 percent oversubscribed – meaning that more than 50 percent as many premises need to be served by satellite than is possible given capacity.
   If all 2,400 base stations which are assumed for a full fixed wireless deployment are built, ~30,000 premises will be left unserved across 14 beams (assuming no FTTN build and spectrum has been secured in the current 'no spectrum' areas). Of these beams, 7 are more than 50 percent oversubscribed. Capacity shortfalls tend to be concentrated in beams covering large population centres – Sydney (Beam 42), Brisbane (Beam 25), Sunshine Coast (Beam 20), Perth (Beam 66) and Melbourne (Beam 51) are among the most oversubscribed beams. This is shown in exhibit 14-2. Although the satellite beams covering these areas generally have a higher capacity than other beams, and the large majority of premises in these dense areas is served via fixed line and fixed wireless, a high number of 'residual' premises remain to be served via satellite.

NBN launches first broadband satellite
News article written by Corbett Communications. The statements made or opinions expressed do not necessarily reflect the views of Engineers Australia.

At 6.4 tonne each, Sky Muster and its twin are among the largest commercial satellites ever launched. The satellites use the Ka spectrum band to allow for greater bandwidth, with 101 individual “spot beams” tailored to Australia's widely distributed rural population, according to NBN. The beams will cover the whole of Australia and five offshore locations: the Christmas, Cocos, Lord Howe, Norfolk and Macquarie Islands.

Wholesale internet speeds provided by the system are expected to be significantly faster than those currently available. According to NBN, the two dedicated satellites will deliver up to a combined 135 Gbps of capacity, more than 30 times the capacity of the existing Interim Satellite Service (ISS) instituted by NBN in 2011. Wholesale download speeds will be up to 25Mbps, around five times that which is currently accessible on the ISS.

Sky Muster a small step forward for NBN

The two NBN Co satellites will provide total throughput of 135/40 Gbps and this capacity is allocated to varying size cone antennas that provide 101 varying size spot shaped coverage regions, some of which overlap slightly. What this means is that if customers were guaranteed a minimum of 25/5 Mbps at all times then there could only be about 5400 customers connected to the satellites.

Using a typical traffic contention ratio of 80/1 the number of connections possible becomes 430,000 but the traditional telecommunications approach to utilise high contention ratios has a downside, and this occurs during peak times when the majority of customers want simultaneous access. The growth of streaming media means that during peak times not only are customers accessing the internet and social media but they’re also trying to access streamed media which requires a reliable connection with low latency and stable throughput.

The government’s plan to utilise a 40/1 contention ratio to connect about 200,000 customers to the satellites has a high risk of failure because the congestion during peak times might overwhelm the satellites creating a massive slow-down for every customer.

The congestion problem caused by high contention ratios is exacerbated when customer usage shifts from viewing discrete small items of content such as a web page on a social media site to watching YouTube videos and streamed movies.

NBN Co has put in place usage rules that will limit customers to 50 GB per four week rolling aggregated usage period measured weekly and customers that exceed this limit will have their download connection speed limited to 128 Kbps for the next two weeks. It has also implemented a 9.7 GB download limit for individual items of content or streamed media.

Just how fair is nbn’s proposed Satellite Fair Use Policy?

As seen above, this averages out to be around 125 kbps per user on CVC Class 0, 145 kbps per user on CVC Class 1 and 190 kbps per user on CVC Class 1.

In comparison, the dimensioning of nbn‘s Fixed Wireless network allocates roughly 500 kbps per-user and 40 kbps on the current nbn Interim Satellite Service (ISS). Capital-Markets-Day-2015

Eutelsat reports provisioning of 40-80 kbps per subscriber (forward channel).


ViaSat reports that a surprisingly small amount of the total data used is from streaming.  Streaming at 500 kbps accumulates about 225 MB of traffic in just one hour.   The only take-away is streaming is not as prevalent as one might expect.
ViaSat indicates that 20% percent of all data used is for streaming applications