FTTH vs DOCSIS (II): The future of Gigabit capable technologies
2020-10-29

In previous articles, we have talked about the importance of achieving a best-in-class network experience to improve customer satisfaction, retention and acquisition.

 

Network and service stability, reliability and capabilities, such as very high speed and ultra-low latency, are the name of the game when it comes to improved customer experience. These quality-related parameters may provide new ways for operators to differentiate themselves, particularly as bundle packages and customers become more sophisticated. Indeed, improved customer experience and satisfaction are vital as operators focus on retention and cross-selling new services.

 

The Gigabit broadband race between cable TV providers and fixed-line carriers to differentiate on broadband speeds has been heating up for a while as bundling became the norm for residential customers, more players combined connectivity and content options and demand rose for increasing bandwidths.

 

For a regular household or even high-demand users, 100-300 Mbps broadband offers with symmetric downlink and uplink speed would be enough, as we pointed out in our recent post about ‘How fast is enough to enjoy our #StayAtHome?’. However, to guarantee a satisfactory experience, some operators are exploiting other quality and performance drivers beyond speed.

 

Recent Huawei’s White Paper (Customer support Services. A value quantification model and white paper) identifies network quality and network service experience as a key differentiator for operators and one of the key factors determining customer satisfaction, respectively. High-quality, advanced, and reliable telecommunications services are instrumental for the customer acquisition and retention challenge. As stated in the report, “subscriber experience will affect revenue in the long run, and a more stable network environment is an important means to improve subscriber experience and engagement. Therefore, the brand value brought by an excellent subscriber experience is an important factor for operators to maintain invincible positions.”

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Key challenges in the Telecommunications Industry July 2020 | Source: HUAWEI

 

In our first article of this series we introduced some key wired technologies that allow us to currently have ultra-fast Internet access at residential premises and enable improved quality of service (QoS) and quality of experience (QoE). Then, we go in depth:

 

VDSL2 Vplus/35b (Super-Vectoring) is a DSL standard for short local loops over copper twisted pair. It allows download speeds up to 300 Mbps (up to 100 Mbps upload) over a distance of up to 250 m to the DSLAM. Super-vectoring is standardized as ITU-T Recommendation G.993.2. See recent news about Super-Vectoring take-up in Germany, as Telekom Deutschland is using this technology to offer downstream speeds of up to 250 Mbps.

G.fast is a DSL standard for local loops over copper twisted pairs shorter than 500 m, with download speed targets between 100 Mbit/s and 1 Gbit/s. G.fast is standardized as ITU-T Recommendation G.9701. See recent news about Openreach’s G.fast “ultrafast broadband” (100 Mbps+) refocusing in the UK.

Fibre to the Premise (FTTP), referred to as FTTH or full fibre broadband as well – Gigabit-capable Passive Optical Network (GPON) is standardized as ITU-T Recommendations G.984 and extends fibre all the way to or inside of the customer premises. It allows download speeds of up to 2,488 Mbps (up to 1,244 Mbps upload, in separate wavelengths) over a distance of 20km. GPON can be upgraded by reducing the number of users per OLT or to newer standards with no change to the fibre components of the outside plant, such as XGS-PON or NG-PON2

Hybrid Fibre Coaxial (HFC) networks, referred to as cable, – Cable networks turned out a major broadband access solution, where optical fibre and coaxial cables are used in different parts of the network. Data-Over-Cable Service Interface Specification (DOCSIS) 3.x is the mostly used standard in cable networks ratified as ITU-T Recommendation J.222 but developed by CableLabs. It allows speeds of up to 10Gbit/s downstream and up to 1Gbit/s upstream.

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Loop length and downlink capacity, copper broadband technologies | Source: Analysys Mason


Considering the growing demand for increasing bandwidths and customer usage extended across several devices simultaneously, is the xDSL technology death closer, now more than ever?

 

Moffett Nathanson argues, in a new research note regarding the US market, that “broadband is increasingly a two-horse race between cable and telco FTTH, where it exists”. With the coming advent of DOCSIS 4.0 would not be sensible to argue that fibre has a technological advantage over cable.

 

Furthermore, Analysys Mason’s recently published relevant forecasts (Full-fibre access as strategic infrastructure: strengthening public policy for Europe) based on the analysis of operators’ plans and projections, and on expected regulatory developments: “Coverage of FTTH is expected to exceed 70% in 11 countries by 2025. Coverage in Spain and Portugal is expected to be close to universal, and in France, Ireland and Sweden is expected to exceed 90%. However, coverage in 6 countries, including Germany, is expected to be less than 40%. We expect overall European coverage to reach 64.4% by the end of 2025.”

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Estimated percentage of premises passed by FTTP, European plus selected benchmark countries, 2025| Source: Analysys Mason

 

FTTH has usually been the preferred choice for operators expanding into greenfield environments bringing fibre directly to the customer premise in a cost-effective manner since there is no legacy deployment in place and less physical or regulatory obstacles.

 

Alternative network (altnet) ISPs are, according to FTTH Council, still constituting the largest part of FTTH/B players, with a contribution of around 56% of the total fibre expansion in Europe, while 41% of homes are passed by former incumbent operators.

 

Recently, operators that initially focused their attention on FTTC–VDSL roll-outs are now seeking to upgrade these networks to FTTP, for example Eir in Ireland, Openreach in the UK, or Telecom Italia.

 

According to a recent Arthur D. Little’s report Open Access Fibre: New investment opportunities opening up for gigabit broadband in Europe, “fibre-based broadband provides better customer experience to the end user. The value proposition is not just high speeds, but also the increased quality of services the customer perceives while using broadband. It gives the telco an opportunity to up-sell new partner content, such as streaming services, etc.”

 

In this sense, FTTH GPON provides speeds of 2.5 Gbps downstream and 1.2 Gbps upstream. As demand for bandwidth increases, operators will either upgrade to XGS-PON with symmetrical rates of 10 Gbps, or upgrade directly to NG-PON2, which provides speeds of 40 Gbps downstream and 10 Gbps upstream – with 40 Gbps upstream as an option. Further than that, the roadmap for 50Gbps and above PONs is covered with 25/50GPON and 100GPON, not standardised yet.

 

Regarding latency, FTTH deployments usually offer lower values than copper acceleration technologies and cable.

 

On the other hand, DOCSIS technology, continued improvements have been ensuring that cable technology stays ahead of the innovation curve. Since the initial production of DOCSIS 1.0 devices in the late 90s to the present day, with DOCSIS 3.1 capability, cable technology has enabled significant speed and performance growth. This means that end users will surely have access to fast and reliable cable Internet service that is capable to meet their everyday needs.

 

The Cable Industry is already planning for some changes as it is going to continue to support the increasing bandwidth needs. Some cable operators are considering a parallel fibre network over the top of their existing network to be operated in parallel at least during a transition period. Other cable operators are following the evolutionary path while expanding their per-customer bandwidth capacity through the HFC system with the use of new technologies as they become available.

 

HFC technology evolution will require decommissioning miles of old coax and running fibre closer to the customer premises and increasing their node counts by a factor of 10 or 20, and the “last mile” will become closer to a “last meter.”

 

The specifications of the new DOCSIS 4.0 version have already been displayed. This technology promises to support up to 10 Gbps speeds downstream capacity and up to 6 Gbps upstream capacity thanks to the extended spectrum (up to 1,8 GHz), and the Full Duplex transmissions will be able to deliver multi-gigabit services with symmetrical connections over HFC networks.

 

Although, it will be some time before DOCSIS 4.0 enters the scene, both active and passive components will require to be replaced to upgrade the current equipment’s from DOCSIS 3.x to 4.0.

 

However, some experts consider that  “there is no imminent sense of urgency for cable operators to adopt DOCSIS 4.0, particularly in Europe (save for countries such as Spain and Germany), where some operators have already upgraded their plant to 1.2GHz and have upstream spectrum built out to 85MHz or even as high as 200MHz”, according to Hanno Narjus, senior VP at Teleste.

 

Having said this, Vodafone Deutschland intends to test DOCSIS 4.0 in a trial next year, provided that the first hardware prototypes are available, according to recent statements from Peter Breitwieser, head of product management cable fixed at Vodafone Deutschland. Depending on the upgrade stage and network topology, DOCSIS 4.0 will allow a downstream data rate of up to 10Gbps and an upstream data rate of up to 6Gbps. With the currently used DOCSIS 3.1, Vodafone Deutschland offers up to 1Gbps downstream and up to 50Mbps upstream in the existing frequency spectrum up to 862 MHz.

 

Is the bandwidth capacity offered by DOCSIS 3.1 today adequate for the coming years? The figure bellow illustrates that the DOCSIS 3.1 10 Gpbs bandwidth capacity limits may become a limiting factor in the future according to Commscope, around the mid-2020’s.

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Required DOCSIS 3.1 bandwidth capacity. | Source: Commscope

 

DOCSIS 3.1 uses 1.2 GHz bandwidth and the theoretical throughputs are 10 Gbps in download and 1Gbps in upload over a single cable. Most deployments use one cable to reach multiple houses, so the total capacity is shared between those customers. Modern head ends usually drive signals down fibre optic lines to smaller “nodes,” each of which uses coax to serve dozens or even hundreds of subscribers. Furthermore, the maximum speeds can only be reached with “deep fibre” HFC setups, where most of the last mile is fibre and a relatively short length of high-quality coax connects the node to the customer.

 

One of the disadvantages of DOCSIS 3.1 is the asymmetry between upload and download speeds. As usage patterns are changing, Cable operators will have to upgrade their systems sooner or later if they want to keep up with the demand for upstream throughput of modern applications.

 

DOCSIS 3.1 deployments also suffer from issues related to latency and jitter. For example, to handle higher noise rates or significant attenuation in older cable and deliver consistent throughputs, DOCSIS employs sophisticated encoding schemes which offer better robustness at the expense of some ms of extra latency. Depending on the encoding scheme, there will be a trade-off between guaranteed latency and increased packet loss and jitter due to noise.

 

As per the European Commission studies, with DSL, cable access, the optical fibre technology, a variety of wired broadband technologies are available on the market that ensure reliable broadband services. However, their capabilities differ considerably among them. The main characteristics of each technology are summarized below for a quick comparison at a glance.

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Main characteristics of each technology.

 

We have seen that cable technologies still have fuel in the tank and could deliver accordingly DOCSIS 4.0. Industry insiders said to Lightreading that the technology “could provide another five to six years of runway, and a future version with a 3GHz ceiling could provide several years more – all postponing the need for most operators to go with expensive fibre-to-the-premises upgrades.”

 

The question of the best customer experience is hard to answer for us, but you may find some insights in the capabilities, other than bandwidth or true speed, that are usually not part of a commercial offer. For example, if we look at other basic performance and quality metrics, such as latency, jitter or even packet loss we will understand that the devil is in the details.

 

The growing number of applications that for example require very low latency levels, such as like voice-over-IP, remote-controlled robotics, virtual/augmented reality, HQ video conferencing or online cloud and multiplayer gaming could change the way we see things. This is already opening opportunities for differentiation, customer acquisition, customer retention and additional revenue streams. What do you think about guaranteed ultra-low latency commercial broadband packages? More and more operators are focusing their efforts on this from a commercial and technical point of view, such as AT&T in the USA or Hyperoptic in the UK.

 

Low latency is desirable to achieve smooth customer experience without lagging. As Gaming is a billion-dollar industry with billions of players it is clearly becoming a key driver for the Telco industry. However, latency has also implications for non-gamers as other time sensitive applications become mainstream. In the Cable industry Low-latency DOCSIS 3.1 (LLD) has been heating up, while enabling latency improvements for certain applications, like video chat or online games, by prioritizing some types of traffic over others at the modem level.

 

With all these technological evolutions come increasing expectations, new use cases and complexity, particularly during deployment, provisioning, testing or maintenance. Along with the deployment strategy, operators need a service and network testing and monitoring solution to follow up with technological developments. Thanks to our End-to-End, customer centric and no-integration approach, MedUX solutions work now and as the network evolves offering an efficient and cost-effective alternative to operators.

 

MedUX HOME solutions analyses the QoE and performance metrics of residential broadband services from the end-user perspective. The metrics are collected in the home networking environment, including the performance of fixed-broadband and Wi-Fi interfaces, allowing our clients to monitor the true Customer Experience. MedUX tracks most-used services, such as YouTube, WhatsApp, Facebook and Netflix, known as Over the Top (OTT) applications.

 

In the end, end users unconsciously expect other performance and quality metrics coupled with speed, “they want an ultra-high-speed connection and no conditions attached […] In the longer run, the Covid-19 experience might stimulate demand for an ultra-reliable and over-provisioned fat pipe for all eventualities”, according to Analysys Mason study.


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