The United Kingdom’s national cable operator, Virgin Media, has confirmed to ISPreview.co.uk that the still in-development DOCSIS 3.1 (DOCSISNG) standard, which could one day deliver cable-based broadband ISP speeds of up to 10Gbps (Gigabits per second), is something they’re testing for the future. But what does it mean?
Virgin’s current cable platform is somewhat of a hybrid network that installs fibre to a local node (FTTN) and then delivers the final connection to homes via a short run of copper or high-grade coaxial cable (HFC). The network is largely based off a EuroDOCSIS variant of the ‘Data Over Cable Service Interface Specification’ (DOCSIS3).
In theory the current network gives Virgin Media room to push their speeds up to 200Mbps or possibly even 400Mbps if 8 downstream channels are bonded, although the extra capacity costs, lack of clear demand and possible negative impact on other services that achieving 400Mbps could have might not make it viable just yet. But a boost to 200Mbps or faster is expected. In the meantime customers are already being offered packages of up to 120Mbps.
But Virgin has also found ways to manipulate its platform to deliver trial download speeds of up to 1.5Gbps (150Mbps upload) to businesses in East London, which uses the same network as its domestic customers (here). Last year another cable network adopted a similar setup to demo a 4.5Gbps connection, although this required over 128 DOCSIS downstream channels into a single fibre node. Neither solution would be viable for home users but they do show that cable networks don’t have to switch to a fully fibre optic (FTTH) network just yet.
A VirginMedia Spokesperson told ISPreview.co.uk:
“We continue to test various speeds to be ready for when we think the time is right to pre-empt consumer demand and maintain our lead as the UK’s fastest widely available broadband company.”
However, despite DOCSIS 3.0 being established all the way back in 2006, cable standards have not been standing still.
In October 2012 CableLabs finally unveiled their plans for the new DOCSIS 3.1 specification, which could eventually push cable download speeds all the way up to the dizzy heights of 10Gbps (1Gbps uploads).
The new standard aims to achieve this by harnessing the power of Orthogonal Frequency Division Multiplexing (OFDM), which has been used on all sorts of networks to split a single signal into multiple frequencies (each of which can carry data), and improved error correction (Low Density Parity Check). On top of that cable networks will also need to boost their radio frequency spectrum allocations.
Early estimates suggest that such enhancements could add as much as 50% extra capacity to cable networks and would still be backwards-compatible with existing DOCSIS gear (CPE), which is a vitally important consideration and would help to keep upgrade costs under control (CPE changes are often one of the most complicated elements to update).
A Virgin Media spokesperson confirmed to ISPreview.co.uk that they “could theoretically integrate this into our existing network” and without too much trouble thanks to its backwards compatibility. But the specifications are still under development and as a result Virgin are currently only experimenting with such solutions as “an exercise … rather than a trial“.
The spokesperson added that Virgin Media expected the upgrade costs for such work to be “relatively minor” in contrast to the “many billions needed to create BT’s FTTC network“. It should however be noted that BT’s network covers most of the UK and it was upgrading from a pure copper platform (Virgin reaches about half of the country.. mostly in urban areas), thus the comparison isn’t entirely balanced. Virgin added that moving to DOCSIS 3.1 would require a similar effort to the £110m they’ve already spent on doubling speeds for over 4 million of their customers.
Meanwhile the current CableLabs time-table for DOCSIS 3.1 development suggests that the preliminary specification should be ready within the first half of 2013, while the first trial kit could be ready for proper testing in early 2014. Sadly few expect the final hardware to be available before 2015.
At this stage it’s still far too early to know what home consumers could expect to get from the platform update, although it’s not unreasonable to predict that a 400Mbps+ service under DOCSIS 3.1 would be very viable and without an excessive upgrade cost, relatively speaking. Delivering affordable speeds like that would put a lot of pressure on BT’s slower FTTC service, especially with the faster FTTP-On-Demand alternative set to be quite expensive (installation fee).
In theory Virgin’s home connectivity under DOCSIS 3.1 could eventually approach 600-800Mbps (the 10Gbps figure would only be viable for business users) but that’s just speculation until we see how the new standard works in a real-world environment. On top of that Virgin’s recent peering and congestion problems show that upgrading the infrastructure is only ever half of the battle.
UPDATE 7th March 2013
Virgin Media’s network man, Phil Oakley, and Ralph Brown, CTO of CableLabs, have told the Cable Congress 2013 conference in London that broadband download speeds of 1Gbps could in theory arrive in homes by 2015 or 2016 (much as we first suggested above).