A “101” on DOCSIS® Technology: The Heart of Cable Broadband
Welcome to the first installment of our CableLabs 101 series about a suite of breakthrough technologies that are instrumental in the path toward the cable industry’s 10G vision—a new era of connectivity that will revolutionize the way we live, work, learn and play. These technologies work together to further expand the capabilities of cable’s hybrid fiber coaxial (HFC) network by increasing connection speeds and capacity, lowering latency and enhancing network reliability and security to meet cable customers’ needs for many years to come.
What Is DOCSIS?
Initially released by CableLabs in 1997, DOCSIS—or Data Over Cable Service Interface Specification—is the technology that enables broadband internet service over an HFC network, now used by hundreds of millions of residential and business customers around the globe. It is essentially the set of specifications that allows different cable industry vendors to design interoperable cable modems (the piece of network equipment that sits in the home) and cable modem termination systems (CMTSs—the network equipment that sits in the cable operator’s hub site). The CMTS is a head-end traffic controller that routes data between the modem in the home and the internet.
DOCSIS technology helped usher in the era of broadband and “always on” internet connections, enabling a wave of innovation that continues to this day. With DOCSIS technology, internet customers were no longer forced to use dial-up solutions that tied up home phone lines and probably caused a significant spike in family feuds. The DOCSIS solution changed everything. Not only did it allow for an “always-on” cable connection (no dial-up required!), it was also significantly faster than dial up. We’ll talk about connection speed—along with capacity, latency and other network performance metrics—and how they affect you a little later in this article.
How Does It Work?
DOCSIS technology governs how data is transmitted over the HFC network. To understand how it works, we need to start with the HFC network—the physical infrastructure that most cable companies use to provide high-speed internet connectivity to their customers. As the name suggests, the HFC network is composed of two parts: the fiber optical network and the coaxial network. HFC networks are predominantly fiber, as illustrated in our recent blog post. The remaining portion of the HFC network is coaxial cable. The coaxial network is connected to the optical fiber network at a “fiber node,” where the (fiber) optical signals are converted to radio frequency electrical signals for transmission over the coaxial network to the subscriber’s home. The HFC network seamlessly transmits data from the CMTS to your cable modem (we call this “downstream” or “download” traffic) or from your modem back to the CMTS (“upstream” or “upload”). In turn, the CMTS is connected to the internet via a set of routers in the service provider’s network.
Think of the HFC network as a “highway” and the data as traffic moving in “lanes” in either direction. In the downstream direction, DOCSIS devices translate the data from the internet into signals carried on the fiber optic portion of the HFC network and then down the coaxial network to your modem. On the upstream, the data that you upload is sent back up the network on a separate upstream “lane.” Traditionally, this “highway” has had more lanes dedicated to the downstream traffic than upstream, which matches current customer traffic patterns. All of this is about to change with the 10G vision, which strives toward symmetrical upstream and downstream service speeds.
How Has This Technology Evolved?
DOCSIS technology has come a long way since 1997. Over the years, it has undergone a few iterations, through versions 1.0, 1.1, 2.0 and 3.0 to 3.1. As DOCSIS has evolved, it has gotten faster by adding more lanes in each direction and it has become more energy-efficient as well. Along the way, several additions to the base technology have been continuously added. These include enabling lower latencies, increased security of the traffic, and tools to make the network more reliable. Today’s cable networks leverage DOCSIS 3.1 technology, which has enabled the widespread availability of 1 Gbps cable broadband services, allowing us to easily enjoy services like 4K video, faster downloads, seamless online gaming and video calls.
DOCSIS 4.0, released in March 2020, is another stepping stone toward that 10G vision. It will quadruple the upstream capacity to 6 Gbps, to match changing data traffic patterns and open doors to even more gigabit services, such as innovative videoconferencing applications and more. DOCSIS 4.0 equipment is still in the process of being developed and is seeing great progress each day toward device certification. Once certification is complete, cable vendors will start mass-producing DOCSIS 4.0-compatible equipment. With the widespread deployment of DOCSIS 4.0 technology, cable operators will have the ability to offer symmetrical multigigabit broadband services over their HFC networks.
How Does This Technology Affect Me and My Future?
All this talk about connection speeds, low latency, reliability and other performance metrics matter to us technologists because it’s how we gauge progress. But it’s so much more than giga-this and giga-that. These metrics will directly impact your future in a real, tangible way.
Over the past two decades, high-speed internet connectivity went from an obscure tech geek novelty to an important part of modern life. We are now streaming in 4K, collaborating on video chat, playing online games with people around the world, driving connected cars and so on. Continuous advancements in DOCSIS technologies are helping make this reality possible by increasing download and upload speeds, lowering latency—or lag—for a more seamless experience, and improving reliability and security to protect our online information.
DOCSIS 4.0 technology will enable symmetrical multigigabit services, ushering in a new wave of innovation across industries and applications, including healthcare, education, entertainment, collaboration technologies, autonomous vehicles and many more. In the near future, we will see advanced health monitoring services, immersive learning and work applications, visually rich VR/AR, holodecks, omnipresent AI assistants and other game-changing innovations that we haven’t even thought of yet. In many ways, the reach and flexibility of cable’s HFC infrastructure is the backbone of our 10G future, and DOCSIS—in combination with other advanced network technologies—is key to helping us reach this Near Future.
On the Path to 10G: CableLabs Publishes Flexible MAC Architecture Specification
Today we are pleased to announce the release of the Flexible MAC Architecture (FMA) library of specifications. Along with the FMA System specification, we are also releasing the FMA MAC Manager Interface (MMI) and the FMA PacketCable Aggregator Interface (PAI) specs. This is the culmination of thousands of hours of work across the cable industry, on a global scale.
The FMA project is a part of the larger Distributed Access Architecture program at CableLabs. This program includes Remote PHY (R-PHY) as well as other projects like DOCSIS 4.0, Coherent Optics and others. FMA defines the standardization of the complete disaggregation of the CCAP management, control and data planes. The specification provides standard interfaces between OSS/NMS/Orchestration and the FMA management and control planes as well as a standard interface abstraction layer to cable access equipment. All of this allows for vendor independence and equipment interoperability.
As a part of the suite of technologies that support the 10G platform, FMA is a key disaggregated access network architecture that supports DOCSIS 4.0 requirements to achieve downstream speeds up to 10 Gbps and upstream speeds up to 6 Gbps. The FMA technology is complementary to the R-PHY technology and together complete a toolset of disaggregated technologies to support an operator’s next-generation data services.
FMA specification work started in late 2017 and was described in a February, 2018 video blog post. When this project kicked off at the behest of the cable industry, CableLabs and its partner vendors worked with an operator steering committee to define the scope of the project that set the wheels in motion for the development of the specification and issued release today.
What’s Next For FMA
The issuance of the specification is the initial step in a comprehensive process in order for CableLabs vendor partners to develop products and ultimately for operators to deploy those products and provide 10G services. We will continue to develop the specifications and it is our plan to begin FMA in-depth interoperability events in 2021.
If you would like to participate in the FMA working group activities, please make your request via firstname.lastname@example.org.
With Great Bandwidth, Comes Great Responsibility
Cable's next generation, 10G networks, holds the promise to deliver symmetrical multi-gigabit speeds that are 100 times faster than what some consumers are currently experiencing today. This great leap forward will enable services and experiences that will drive internet innovation for years to come. It is our mutual responsibility to assure that devices we connect to these blazing 10 gigabit internet connections, are updated and patched, free from default passwords and use proper authentication and authorization.
The lack of following basic cyber-security principals surfaced in the late Fall of 2016, when many popular sites such as Twitter, Amazon, Reddit and Netflix, were unreachable for several periods, lasting hours. The cause was a massive distributed denial of service (DDoS) attack coming from hundreds of thousands of compromised internet of things (IoT) devices. Traffic from these devices overwhelmed the DNS service provider dyn.com and effectively blocked customers and users from reaching these popular Internet locations for hours at a time.
As we approach a world where households are connected at gigabit and greater speeds, building secure devices and getting them in the hands of consumers is essential. Over the last several years CableLabs has been engaged with standard organizations such as, the Consumer Technology Association (CTA) and the Open Connectivity Foundation (OCF), to draft specifications and guide security baselines for IoT devices. This work has culminated in the release of OCF's international ISO\IEC specification for IoT interoperability.
The OCF specification brings together over 450 member companies and work that spans half a decade to apply cyber-security best practices to the IoT. This specification, combined with an open source reference implementation, seven approved global testing and certification labs and an active community of practitioners and member companies (from device vendors, network device venders and network operators), is uniquely positioned to be the secure standard that unites the industry.
With the OCF specification a consumer can buy a certified device from Vendor A and be confident in the knowledge that not only will it work with their certified appliance from Vender B, but it will do so in a way that is encrypted and authenticated. OCF can work with many cloud services but does not inherently need the cloud, promising consumers a good balance between the convenience of the cloud and the privacy and availability of their local networks.
The OCF specification's security-first approach brings it into close alignment with several of the security guidelines from government and industry, including:
- National Institute for Standards and Technology (NIST) NISTIR 8259 draft of recommendations IoT device manufacturers.
— OCF meets 6/6 requirements
- The Consumer Technology Association (CTA) C2 Consensus on IoT Device Security Baseline Capabilities.
— OCF meets 10/10 requirements
- UK's Code of Practice for Consumer IoT Security.
— OCF meets 11/13 requirements (other two requirements are aimed at service providers not device requirements)
- European Union Agency for CyberSecurity (ENISA) Baseline Security Recommendations for IoT.
— OCF meets 40/57 requirements (most unmet requirements are not applicable to a device centric model)
The road ahead for 10G and IoT is bright. Ultra-fast networks and connected devices have the potential to change every aspect of daily life, making our surroundings aware and interactive to our presence and able to predict and adjust to our needs. Work, entertainment and social interaction will happen whenever and wherever we are, dynamically and organically. Education and healthcare will be forever changed as sensors and ubiquitous devices allow us to interact in ways never before possible. Yes, the future is bright, but it also must be secure.
CableLabs Honored with a New Technology Emmy
This awards season, CableLabs won a Technology and Engineering Emmy Award for enabling development and deployment of the Hybrid Fiber Coax (HFC) Network Architecture—the suite of technologies responsible for the razor-sharp broadband video, high-speed Internet you enjoy today.
These Emmy awards aren’t easy to snag—although we previously received one in 2010 for DOCSIS 3.0 technology. They’re awarded only once per year to individuals and companies whose technologies have made an extensive and significant impact on the transmission, recording and reception of television. Essentially, the awards recognize technologies that have revolutionized the industry. That’s inarguably true of HFC and, specifically, the AM laser technology that replaced the very long and unreliable amplifiers in cable distribution plants. AM lasers substantially reduced noise and distortion and increased the plants’ bandwidth, paving the way for high-capacity digital services such as HDTV, Video on Demand, high-speed Internet connectivity and more. In just a few decades, cable operators have universally adopted HFC technology, deploying more than 500,000 miles of optical fiber worldwide.
CableLabs’ Contribution: A Little Bit of History
In many ways, what’s known today as HFC technology is a joint effort to improve the reliability of cable technologies devised in the early 1980s. Prior to 1985, cable systems had long cascades of amplifiers, the failure of which affected service to large populations. In search of a solution, Time Warner—and later, Ortel—began experimenting with using fiber deep in the system with much shorter legs of coax and only a few amplifiers in each leg. The results were very promising—much better picture, reduced noise and greater overall system reliability.
After the initial test trials, the challenge was to make this technology economically viable for larger-scale commercial deployments. This is where CableLabs has played a monumental role. In 1988–89, newly formed CableLabs (led by Dick Green) drove the effort to standardize the application of HFC technology and facilitate collaboration between cable operators and industry vendors, resulting in rapid performance improvements and reduced cost. It is this collaboration across cable operators, industry vendors and CableLabs – and other industry partners – that remains the hallmark of CableLabs’ continued success today.
What’s Next for HFC: The Road to 10G
HFC technology has been around for over 30 years and is still going strong, providing the platform for countless gigabit data services, like Ultra HD and more. It’s also the basis for the cable industry’s 10G platform, which aims to provide faster speed, lower latencies, enhanced reliability and better security in a scalable manner. Achieving this goal will open the door to a whole new wave of innovations, such as full-immersion virtual reality (VR) gaming, artificial intelligence (AI) applications and other technologies that will revolutionize the way we live in the near future.
One of the major advantages of HFC architecture is its ubiquity, which allows the cable industry to make quick performance improvements without any major, expensive overhauls to the system. And although we at CableLabs are deeply honored to receive recognition for our contribution, our work on HFC is far from over. We’ll continue working with our members and partners to unleash HFC’s full potential, building on our existing foundation to deliver a fast, reliable and secure network of the future.
The 72st Annual Technology and Engineering Emmy Awards will take place in partnership with the National Association of Broadcasters (NAB), at the NAB Show at the Wynn Encore Hotel and Spa on Sunday, April 19th, 2020 in Las Vegas, NV.
Acknowledgment of Significant Individual and Corporate Contributors:
|Time Warner / ATC||Jim Collins, Jim Chiddix, Louis Williamson, Dave Pangrac, Don Gall, John Walsh, Jim Luddington, Jay Vaughn|
|TCI||John Malone (who was also Chairman of CableLabs), J.C. Sparkman, Richard Rexrote|
|Ortel||Hank Blauvelt, Larry Stark|
|ANTEC / AT&T Bell Laboratories||ANTEC – John Egan
AT&T Bell Laboratories – Bob Stanzione, Carl McGrath, Gerry Fenderson
|Jerrold / General Instrument||David Grubb, Steve Frederick, Geoff Roman|
|Scientific Atlanta||Dave Fellows, Lee Thompson, Frank Little, Rezin Pigeon|
A Major Leap Toward 10G: CableLabs to Complete DOCSIS® 4.0 Specification in Early 2020
In a continuing effort to meet the industry’s recently announced 10G goal, CableLabs is wrapping up the first major update to its DOCSIS specification since DOCSIS 3.1. DOCSIS 4.0 technology will enable the next generation of broadband over cable’s existing hybrid fiber coax (HFC) networks, delivering symmetrical multi-gigabit speeds while supporting high reliability, high security and low latency.
What is DOCSIS 4.0 Technology?
Building on the success of DOCSIS 3.1 technology, which the cable industry is leveraging globally to deliver 1 Gbps services to end users, DOCSIS 4.0 technology supports a rich and flexible feature set of capabilities. The technology will enable multiple system operators (MSOs) to deliver on the 10G vision and includes support for Extended Spectrum DOCSIS (ESD) and Full Duplex DOCSIS (FDX) capabilities. These are complementary technologies that jointly or individually represent key elements to deliver on the 10G promise. By supporting these technologies, cable operators can deliver a richer feature set of capabilities and facilitate a cost-effective upgrade to a better, faster and more efficient network.
- Full Duplex DOCSIS Capabilities
FDX DOCSIS technology allows for concurrent use of spectrum for both upstream and downstream traffic, thus doubling the network efficiency by leveraging the HFC network characteristics, self-interference cancellation technology and intelligent scheduling. DOCSIS 4.0 technology is also backwards compatible with previous generations of DOCSIS technologies.
- Extended Spectrum DOCSIS
With ESD, operators can leverage a lot more usable spectrum on their existing HFC networks—up to 1.8GHz. That’s 600MHz more than the 1.2GHz available to them under the current DOCSIS 3.1 standard. The DOCSIS 4.0 working groups are in full swing, focusing on developing and adding the ESD requirements to the DOCSIS 4.0 specifications.
This boost in capacity provided by DOCSIS 4.0 technology will enable MSOs to provide multi-Gbps symmetric services to residential and business customers, and support the next generation of user experiences such as immersive media experiences in addition to serving as a catalyst for a new wave of innovations.
DOCSIS 4.0 technology is a major step toward reaching the industry’s 10G goal. You can learn more about the road to 10G and its technologies here. If you’re near New Orleans or attending the SCTE Cable-Tech Expo next week, register for our vendor forum, Envision, to get the exclusive opportunity to learn about the technologies the industry is working on. At Envision, which will take place on September 30, you can expect to hear updates about DOCSIS 4.0 technology and 10G, including how 10G will enable mobile and wireless networks.
Gearing Up for 10G: Download the Technical Brief on CableLabs’ Low Latency Technologies for DOCSIS Networks
If you’ve been following our blog and our recent 10G announcement, you know that one of the main areas of focus for us is latency. Achieving a near-zero latency on DOCSIS networks is one of the goals of the 10G initiative and is just as important as increasing speed or bandwidth. The success of future 10G networks that can support seamless communication and next-level interactive experiences like holodecks and 360° video is heavily dependent on finding technological solutions that decrease latency to imperceptible levels, delivering consistent, real-time responsiveness that our customers desire.
The good news is we are well on our way to getting there. So far we’ve released a number of specifications, including Low Latency DOCSIS (LLD) and Low Latency Mobile Xhaul (LLX), aimed at reducing latency in the DOCSIS networks that provide residential services and also serve as backhaul, midhaul and fronthaul (collectively known as xhaul) for mobile traffic.
Low Latency DOCSIS (LLD)
In modern households, there are often multiple applications and devices connected to the same network at the same time, sending and receiving a variety of traffic. Some, like streaming video and large file downloads, send repeated large bursts of data and expect the network to buffer and play-out those bursts, while others, like online gaming and voice chat, send traffic smoothly. Ordinarily, the traffic from the smooth senders is subjected to the widely varying buffering latency caused by the bursty senders. LLD technology is optimized for these two different types of traffic behavior, and decreases delays for smooth sending applications (many of which are latency-sensitive) without affecting the other traffic. Low Latency DOCSIS technology can support a consistent sub-1ms latency round-trip for the smooth sending applications, resulting in a much better network performance overall.
Low Latency Mobile Xhaul (LLX)
LLX leverages collaboration between the mobile network scheduler and the DOCSIS scheduler to provide a low latency xhaul solution that achieves a consistent DOCSIS upstream delay of just 1 to 2 milliseconds. LLX also defines a common quality of service framework for both mobile and DOCSIS so that the relative priorities of different traffic streams are maintained across the two systems. In the foreseeable future, deploying LLX technology will help solidify DOCSIS cable networks as the xhaul transport of choice, capable of supporting the latency requirements of 5G and beyond.
For more detail, please download the following member-only technical brief on Low Latency Technologies for DOCSIS Networks which includes information about sources of latency, how we address them, implementation strategies and more.
If you’re not yet a CableLabs member, find out how you can become one here.
Enabling 5G with 10G Low Latency Xhaul (LLX) Over DOCSIS® Technology
I am a GenXer, and I am addicted to my iPhone. But it’s not just me, today’s consumers, millennials and baby boomers and everyone in between, are increasingly spending more and more time on their mobile devices. Have you ever wondered what happens to your traffic when you interact with your iPhone or Android devices? The traffic reaches a radio tower, but it doesn’t just stop there – it needs to reach the internet via a connection between the cellular base station and a distant data center.
Traditionally, that connection (a.k.a., “xhaul”) is mostly provided by fiber. Fiber has great speed and latency performance but is costly to build. With advancements in LTE and 5G, mobile operators are increasingly deploying more and more radios deeper into the neighborhoods. They will need a more scalable solution to provide that xhaul without sacrificing the performance. This is where the hybrid fiber coaxial (HFC) network can help.
With ubiquitous cable infrastructures that are already in place, the cable operators have the scalability to support today’s LTE and tomorrow’s 5G networks without the cost of building new fiber networks. With DOCSIS 3.0+ as well as Low Latency Xhaul (LLX) technology, the DOCSIS network has performance that is virtually indistinguishable from fiber. The CableLabs 10G technologies make the HFC network a better xhaul network, which is a win-win for the consumers, mobile operators, and cable operators.
How Low Latency Xhaul (LLX) Works
Today’s DOCSIS technology provides a good starting point for mobile xhaul but may not be enough to support the ultimate latency requirements needed for future mobile traffic. DOCSIS upstream latency can range from a typical of 8-12 milliseconds to around a maximum of 50 milliseconds under heavy load. We want to see that latency down to 1 to 2 milliseconds range in order to support 5G.
The LLX technology is specifically designed to reduce the latency experienced by mobile traffic while traversing the DOCSIS transport network on its way to the internet. The LLX technology development started about 3 years ago as a joint innovation project between CableLabs and Cisco. I wrote about it here and here.
So, how does LLX work? Let’s look at the case of LTE backhauled over a DOCSIS network as an example. Today, LTE and DOCSIS are two independent systems – their operations occur in serial, and the overall latency is the sum of the two system latencies. But from an engineer’s point of view, both technologies have a similar request and grant-based mechanism to access the channel. If the two processes can be pipelined, then LTE and DOCSIS operations can take place in parallel, removing the “sum” from the latency equation. To enable pipelining, we designed a protocol that utilizes a message called the bandwidth report (BWR) that allows the LTE network to share information with the DOCSIS network. Pipelining is a unique and inventive aspect of LLX and is the heart of what creates a low latency transport.
So, just how well does LLX work? We have recently teamed up with Shaw, one of our Canadian members, as well as our technology development partners Cisco and Sercomm to perform a series of lab trials. The detail of the trials will be published in the upcoming SCTE Cable-Tec Expo in October. But as a preview, we demonstrated that even when the DOCSIS network is heavily loaded, LLX consistently reduced the DOCSIS upstream latency down to 1 to 2 milliseconds, all without adversely affecting other traffic.
Deploying LLX Technology
The LLX specification was published a few months ago, the result of collaborative efforts from key cable and mobile equipment vendors in the CableLabs-led LLX working group.
LLX technology is designed to work for a variety of deployment models, including backhaul and fronthaul, over DOCSIS as well as over PON networks. To this end, we have taken the technology to mobile industry standardization organizations such as the O-RAN Alliance whose current focus is fronthaul.
LLX works in the DOCSIS 3.0 and later networks as a software upgrade to the CMTS. It has been implemented on commercial DOCSIS and mobile equipment. More information on LLX is available here.
For those attending the SCTE Cable-Tec Expo in New Orleans, we will be discussing the innovation on the Innovation Stage at 12:45pm local time with my industry partners from Shaw, Cisco, and Sercomm. I will also dive deep into the technology and the Shaw trial results in my SCTE panel “Mobile X-haul and DOCSIS”, Wednesday October 2nd at 9am local time. Hope to see you there.
CableLabs Low Latency DOCSIS® Technology Launches 10G Broadband into a New Era of Rapid Communication
Remember the last time you waited (and waited) for a page to load? Or when you “died” on a virtual battlefield because your connection couldn’t catch up with your heroic ambitions? Many internet users chalk those moments up to insufficient bandwidth, not realizing that latency is to blame. Bandwidth and latency are two very different things and adding more bandwidth won’t fix the internet lag problem for latency-sensitive applications. Let’s take a closer look at the difference:
- Bandwidth (sometimes referred to as throughput or speed) is the amount of data that can be delivered across a network over a period of time (Mbps or Gbps). It is very important, particularly when your application is trying to send or receive a lot of data. For example, when you’re streaming a video, downloading music, syncing shared files, uploading videos or downloading system updates, your applications are using a lot of bandwidth.
- Latency is the time that it takes for a “packet” of data to be sent from the sender to the receiver and for a response to come back to the sender. For example, when you are playing an online game, your device sends packets to the game server to update the global game state based on your actions, and it receives update packets from the game server that reflect the current state of all the other players. The round-trip time (measured in milliseconds) between your device and the server is sometimes referred to as “ping time.” The faster it is, the lower the latency, and the better the experience.
Interactive applications, where real-time responsiveness is required, can be more sensitive to latency than bandwidth. These applications really stand to benefit from technology that can deliver consistent low latency.
As we’ve alluded, one good example is online gaming. In a recent survey we conducted with power users within the gaming community, network latency continually came up as one of the top issues. That’s because coordinating the actions of players in different network locations is very difficult if you have “laggy” connections. The emergence of Cloud gaming makes this even more important because even the responsiveness of local game controller actions depends on a full round-trip across the network.
Queue Building or Not?
When multiple applications share the broadband connection of one household (e.g. several users performing different activities at the same time), each of those applications can have an impact on the performance of the others. They all share the total bandwidth of the connection, and they can all inflate the latency of the connection.
It turns out that applications that want to send a lot of data all at once do a reasonably good job of sharing the bandwidth in a fair manner, but they actually cause latency in the network when they do it, because they send data too quickly and expect the network to queue it up. We call these “queue-building” applications. Examples are video streaming and large downloads, and they are designed to work this way. There are also plenty of other applications that aren’t trying to send a lot of data all at once, and so don’t cause latency. We call these “non-queue-building” applications. Interactive applications like online gaming and voice connections work this way.
The queue-building applications, like video streaming or downloading apps, get best performance when the broadband connection allows them to send their data in big bursts, storing that data in a buffer as it is being delivered. These applications benefit from the substantial upgrades the cable industry has made to its networks already, which are now gigabit-ready. These applications are also latency-tolerant – user experiences are generally not impacted by latency.
Non-queue-building applications like online gaming, on the other hand, get the best performance when their packets don’t have to sit and wait in a big buffer along with the queue-building applications. That’s where Low Latency DOCSIS comes in.
What is Low Latency DOCSIS 3.1 and how does it work?
The latest generation of DOCSIS that has been deployed in the field—DOCSIS 3.1—experiences typical latency performance of around 10 milliseconds on the access network link. However, under heavy load, the link can experience delay spikes of 100 milliseconds or more.
Low Latency DOCSIS (LLD) technology is a set of new features, developed by CableLabs, for DOCSIS 3.1 (and future) equipment. LLD can provide consistent low latency (as low as 1 millisecond) on the access network for the applications that need it. The user experience will be more consistent with much smaller delay variation.
In LLD, the non-queue-building applications (the ones that aren’t causing latency) can take a different path through the DOCSIS network and not get hung up behind the queue-building applications. This mechanism doesn’t interfere with the way that applications go about sharing the total bandwidth of the connection. Nor does this reduce one application's latency at the expense of others. It is not a zero-sum game; rather, it is just a way of making the internet experience better for all applications.
So, LLD gives both types of applications what they want and optimizes the performance of both. Any application that wants to be able to send big bursts of data can use the default “classic” service, and any application that can ensure that it isn’t causing queue build-up and latency can identify its packets so they use the “low latency” service. Both then share the bandwidth of the broadband connection without one getting preference over the other.
Incorporating LLD Technology
Deploying Low Latency DOCSIS in a cable operator’s network can be accomplished by field-upgrading existing DOCSIS 3.1 CMs and CMTSs with new software. Some of the low latency features are even available to customers with older (pre-DOCSIS 3.1) CMs.
The technology includes tools that enable automatic provisioning of these new services, and it also introduces new tools to report statistics of latency performance to the operator.
DOCSIS equipment manufacturers are beginning to develop and integrate LLD features into software updates for CMTSs and CMs, and CableLabs is hosting Interoperability Events this year and next year to bring manufacturers together to help iron out the technology kinks.
We expect these features to become available to cable operators in the next year as they prepare their network to support low latency services.
LLD provides a cost-effective means of leveraging the existing hybrid fiber-coaxial (HFC) network to provide a high-performance network for latency-sensitive services. These services will help address customers’ requirements for many years into the future, maximizing the investments that cable operators have made in their networks. The cable industry is provisioning the network with substantial bandwidth and low latency to take another leap forward with its 10G networks.
For those attending the SCTE Cable-Tec Expo in New Orleans, Greg will be presenting the details of this technology on a SCTE panel “Low Latency DOCSIS: Current State and Future Vision”
The 10g platform is going to provide reliable service. As the cable industry embarks on the development of 10G services, there is a lot of work ahead, but we already have a strong foundation of experience and technology to build upon.
The 10 Gbps goal is about performance. But it must come with low cost, high quality, and sufficient reliability. 10G services have to be easy to install reliably, remain stable and robust against cable plant variations and conditions, and provide a wealth of service flexibility so that services remain reliable under a broad set of use cases.
The Road to 10G…
At CableLabs, we’ve taken big leaps toward 10G with DOCSIS® 4.0, including Full Duplex DOCSIS, and with cable modems (CMs) which will be capable of 5 Gbps symmetrical service in the near future. To fully arrive at 10G, we need to enable 10 Gbps downstream speeds. To accomplish that, we’ll need to expand our use of available spectrum, and we’ll likely need to use that spectrum in a highly efficient manner. Pushing higher bandwidth solutions deeper into the network and closer to the edge customers will be required, too. We have a lot of innovation ahead of us to get to the 10G future.
…Is Paved with Innovation
Invention often begins with an initial solution that is later repeated for verification, then validated further. That initial solution then needs to be scaled; in other words, it needs to be made repeatable, at a low cost, and with sufficient reliability.
Fortunately, DOCSIS networking is a technology with many reliability traits integrated. Data are delivered reliably due to Forward Error Correction. Profile management can control the data rate to allow the best performance possible, but not push performance to low reliability. Adjustments to the connection between the cable modem termination system (CMTS) and CM assure reliable transmission continues under constant environmental and network changes. And Proactive Network Maintenance (PNM) assures that plant conditions are discoverable, and that they can be translated into maintenance activities that can further assure services stay reliable at low cost. The cable industry is starting on a solid foundation.
Consider one possible direction we could take on the road to 10G. As we begin to expand the frequencies that DOCSIS uses, we may need improved error correction, better profile management, or better CMTS-to-CM coordination to assure reliable services continue at expected levels. However, pushing these limits might also mean new failure modes in the plant, or greater service sensitivity to existing failure modes, thus increasing the importance of PNM. Operators should up their PNM game now, understanding that it will be an even more important element to assure a reliable 10G future.
A Super Highway in Many Directions
Because of this strong reliability foundation in cable technologies, particularly DOCSIS, we can build our 10G future with reliability in mind. Rather than simply extending our boundaries and hoping that our existing methods to assure reliable services will be sufficient, we can define solutions that bring reliability with them. By focusing simultaneously on increased performance, lower operational costs, and reliable services, we can evolve into an effective, desirable 10G future for the world.
Also, by thoughtfully choosing the technologies to develop, we can create degrees of freedom and opportunities to enhance reliability while developing 10G. This is the right approach for the industry to take because reliability can only be built into a service, not added later. By choosing to develop solutions now that expand our options for reliable services, we can enable operators to have full control of their services. To make it work reliably, PNM will be there, and so will a few other advantages to come.
Now Announcing Wi-Fi CERTIFIED Data Elements™—Inventing the Standard in Wi-Fi PNM
Last year we announced that we’re working with the Wi-Fi Alliance to develop a standard for Key Performance Indicator (KPI) capture in a Wi-Fi network—now officially called Wi-Fi CERTIFIED Data Elements. Optimized and reliable residential Wi-Fi will be critical to deploying 10G and this standard addresses many of the major Wi-Fi PNM-related pain points identified by members of the cable community, such as the following:
- Lack of visibility into customers’ Wi-Fi networks: Often, MSOs must rely on their customers to report Wi-Fi problems after they've occurred, leading to customer dissatisfaction and retention issues.
- Exorbitant cost associated with Wi-Fi troubleshooting: The cable industry wastes more than over a billion dollars per year troubleshooting residential Wi-Fi and two thirds of customer complaints are related to Wi-Fi.
- Lack —or overabundance—of data: There’s currently no global standard for the collection of key actionable data on Wi-Fi network performance in residential, small and midsize businesses, and operator-managed enterprise systems. Data Elements offers a data model focused on what is important for troubleshooting.
- Lack of good options: Although proprietary Wi-Fi PNM solutions exist, they require deployment of costly proprietary technology on customers’ equipment and are too restrictive in terms of analytic capabilities.
The Ins and Outs of Wi-Fi CERTIFIED Data Elements™
Setting Up the Platform
Now that the Wi-Fi CERTIFIED Data Elements code has been released to the open source community, anyone can use it. There’s no proprietary equipment or other restrictions. Cable Internet providers can work with their vendors to get the code implemented on customers’ equipment (CPEs) and certified by the Wi-Fi Alliance. Once the equipment is in place and appropriate cloud servers have been set up, providers can begin to collect and analyze the incoming data.
Collecting the Data
Due to the dynamic nature of Wi-Fi, Wi-Fi CERTIFIED Data Elements focuses on a rapid collection of a few KPIs that are responsible for the majority of customers’ Wi-Fi issues. It supports scheduled and asynchronous data transmission that gives operators unprecedented visibility into customer Wi-Fi network performance without adversely affecting the quality of the connection.
Using the Data
In many cases, operators will be able detect and quickly fix Wi-Fi related issues remotely before customers even notice there’s a problem—saving both time and money that would otherwise be wasted on troubleshooting efforts later on. For example, if a Wi-Fi channel in an apartment building serviced by one MSO becomes too crowded, the system will have the data to automatically recommend a better channel distribution among all the apartments, proactively improving the experience for all the residents before they notice a “slowdown” in the connection. If a customer does report an issue, the support representative will be able to quickly pinpoint the source and offer actionable insights based on the data. For example, if the customer complains about “slow Internet,” the rep will be able to detect whether there’s a coverage problem in the home or whether the customer’s Wi-Fi device can actually support the Internet speed he or she is paying for.
Wi-Fi CERTIFIED Data Elements is a long-awaited solution to many Wi-Fi related issues. Not only will it significantly reduce the barrier to entry for any MSO looking to implement an effective Wi-Fi PNM system, it will also help cut troubleshooting costs and provide a better, more reliable Wi-Fi experience for residential and business customers. We are very excited about sharing this new technology with our members and vendors and are looking forward to its release later this year. Please stay tuned for updates!