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G.fast: What is it?

27th September 2018

Now that Giganet can offer G.fast with its UltraBOLT services, we look into what this new broadband technology can offer the lucky few who will be able to benefit from it.

G.fast is one of the latest ultrafast broadband technologies that can deliver over 100Mb/s (megabits per second) over very short twisted copper lines (or BT/Openreach telephones lines to you and I).
If your copper line length to the G.Fast cabinet is under 300 metres, you may reach download speeds of up to 300Mb/s1 down and 50Mb/s up, which is a considerable jump up from the next fastest copper-line broadband service of VDSL2 (or fibre to the cabinet/ FTTC) that tops out at 76Mb/s down and 19Mb/s up.

G.fast is delivered via a street-side fibre-connected extension cabinet bolted to the serving copper-line cabinet also known as the primary connection point (PCP). G.fast leverages the advances in twisted-copper-line broadband technology to increase the spectrum used (bandwidth), noise mitigation and error correction mechanisms to deliver much faster speeds2; the trade-off being that this is only possible with much shorter copper-line lengths than VDSL2 or ADSL2+.

In some cases fibre-connected G.fast pods are being fitted to telegraph poles and installed in the basements of apartment blocks to reduce the copper line length further.

 

Openreach G.fast network topology

 

G.fast is classed as an Ultrafast broadband technology as it can deliver download speeds of over 100Mb/s that is usually the marker for defining ultrafast speeds. However, unlike full-fibre (FTTP/H) services, speeds over G.fast are likely to fluctuate widely depending on copper line length, conditions, and sources of noise & interference which full-fibre FTTP/H is immune from. G.Fast is broadly affected in much the same way as FTTC and ADSL2+ and ADSL before that have been.

 

Giganet’s G.fast brand name – ‘UltraBOLT’

Giganet brands its G.fast services as UltraBOLT.

  • “Ultra” for ultrafast;
  • “BOLT” for copper technology.

We then define the max headline rate as a number after the service name.

For example, UltraBOLT 300 refers to a G.fast broadband service capable of delivering up to 300Mb/s down (and 50Mb/s up).

 

G.fast differences

What makes G.fast different to the other broadband technologies such as ADSL or FTTC are 3 things:

  1. G.fast delivers up to 300Mb/s (megabits per second) download which is nearly 4x that of FTTC and 13x that of ADSL2+3
  2. G.fast requires very short-copper lines to deliver these faster speeds, so up to 300 metres from the cabinet can deliver ultrafast speeds. Beyond this, VDSL2 (FTTC or our SuperBOLT services) could be better suited.
  3. G.fast availability is extremely limited across the UK, with circa 2 million lines having access to it compared with over 27 million for FTTC and other superfast hybrid copper/fibre services.4

G.fast coverage

 

So far, G.fast has been deployed to around 2 million lines across the UK. We have typically seen G.fast rolled out in large towns or cities in areas with higher population densities as well as overlapping Virgin Media cable areas. There has been a scatter gun approach to Openreach’s rollout plans so it’s hard to uncover the UK-wide picture of deployment.

G.fast is definitely not a rural broadband fix. The requirement of G.fast for very short copper line lengths from the cabinet to the customer means that G.fast practically rules itself out in rural and typically longer line length areas. Contrast this to urban areas, it’s not unusual to see a half a dozen cabinets from one vantage point.

However, in August 2018, Openreach announced they would be scaling back their wider G.fast roll-out and instead focusing on full-fibre to the premises or home. This has results in their aspiration of 10 million G.fast enabled lines by 2020 to be scaled back to 6 million. So far today, (March 2019), they have just reached 2million G.fast enabled lines.

This is something that most should be pleased about, as G.fast is really only an incremental and non-future proofed means of improving broadband speeds, although being faster and less expensive to deploy. Full-fibre can be upgraded (with different electronics/lasers at each end) to many gigabits or terabits per second; far more than we could ever need today!

 

Giganet’s G.fast services

Giganet have a range of business and home G.fast broadband services under our UltraBOLT service name.

We’re including a Zyxel VMG8823 802.11ac Wave 2 Wi-Fi router with each UltraBOLT G.Fast service.

  • Home G.fast UltraBOLT services start from £64/month for up to 145Mb/s down and 30Mb/s up, or £74/month for up to 300Mb/s down and 50Mb/s up on a 12month minimum term. Installation is £195.
  • Business G.fast UltraBOLT services start from £89+VAT/month for up to 145Mb/s down and 30Mb/s up, or £119 for up to 300Mb/s down and 50Mb/s up. Installation is £145+VAT on a 12month minimum term, or FREE on a 36month term.
  • All services come included with the line rental, installation, 802.11ac Gigabit Wi-Fi router, unlimited data transfers, 24×7 core network monitoring, Mon-Fri 9am-5.30pm customer care.
  • Business services include 6hr 24×7 guaranteed fix for critical faults.

 

By Giganet Technical Director, Matthew Skipsey.

 

1 300Mb/s is a conservative estimate on the theoretic maximum speed, but Openreach and we consume this product as a 330Mb/s download rate. There will be overheads and fluctuations to result in 330Mb/s not being able to be achieved, so we quote 300Mb/s.
2 G.fast allows for 106MHz profiles compared to VDSL2 which only has 30MHz. G.fast benefits from Vectoring technology, which is similar to your noise-cancelling headphones work. This helps mitigate cross-talk interference from adjacent broadband lines.
3 G.fast is currently available in the UK across the Openreach and wholesale networks as an up to 330Mb/s down and 50Mb/s service; VDSL2 (or fibre to the cabinet) is currently available via the same Openreach network at up to 80Mb/s down and 20Mb/s up. ADSL2+ typically maxes out at 24Mb/s. All these speeds are physical MAC-layer speeds, and real-world speed tests will render lower speeds due to overheads and other mitigating circumstances.
4 https://www.ispreview.co.uk/index.php/2018/04/ofcoms-spring-2018-uk-mobile-and-fixed-broadband-coverage-stats.html & https://www.ispreview.co.uk/index.php/2018/08/openreach-to-scale-back-rollout-of-g-fast-broadband-focus-on-fttp.html.
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