Expanded Testing of Video Conferencing Bandwidth Usage Over 50/5 Mbps Broadband Service
As working from home and remote schooling remain the norm for most of us, we wanted to build on and extend our prior investigation of the bandwidth usage of popular video conferencing applications. In this post, we examine the use of video conferencing applications over a broadband service of 50 Mbps downstream and 5 Mbps upstream (“50/5 broadband service”). The goal remains the same, looking at how many simultaneous conferencing sessions can be supported on the access network using popular video conferencing applications. As before, we examined Google Meet, GoToMeeting, and Zoom, and this time we added Microsoft Teams and an examination of a mix of these applications. To avoid any appearance of endorsement of a particular conferencing application, we haven’t labeled the figures below with the specific apps under test.
We used the same network equipment from November. This includes the same cable equipment as the previous blog -- the same DOCSIS 3.0 Technicolor TC8305c gateway, supporting 8 downstream channels and 4 upstream channels, and the same CommScope E6000 cable modem termination system (CMTS).
The same laptops were also used, though this time we increased it to 10 laptops. Various laptops were used, running Windows, MacOS and Ubuntu – nothing special, just laptops that were around the lab and available for use. All used wired Ethernet connections through a switch to the modem to ensure no variables outside the control of the broadband provider would impact the speeds delivered (e.g., placement of the Wi-Fi access point, as noted below). Conference sessions were set up and parameters varied while traffic flow rates were collected over time. Throughout testing, we ensured there was active movement in view of each laptop’s camera to more fully simulate real-world use cases.
As in the previous blog, this research doesn’t take into account the potential external factors that can affect Internet performance in a real home -- from the use of Wi-Fi, to building materials, to Wi-Fi interference, to the age and condition of the user’s connected devices -- but it does provide a helpful illustration of the baseline capabilities of a 50/5 broadband service.
As before, the broadband speeds were over-provisioned. For this testing, the 50/5 broadband service was over provisioned by 25%, a typical configuration for this service tier.
First things first: We repeated the work from November using the 25/3 broadband service. And happily, those results were re-confirmed. We felt the baseline was important to verify the setup.
Next, we moved to the 50/5 broadband service and got to work. At a high level, we found that all four conferencing solutions could support at least 10 concurrent sessions on 10 separate laptops connected to the same cable modem with the aforementioned 50/5 broadband service and with all sessions in gallery view. The quality of all 10 sessions was good and consistent throughout, with no jitter, choppiness, artifacts or other defects noticed during the sessions. Not surprisingly, with the increase in the nominal upstream speed from 3 Mbps to 5 Mbps, we were able to increase the number of concurrent sessions from the 5 we listed in the November blog to 10 sessions with the 50/5 broadband service under test.
The data presented below represents samples that were collected every 200 milliseconds over a 5-minute interval (300 seconds) using tshark (the Wireshark network analyzer).
Conferencing Application: A
The chart below (Figure 1) shows total access network usage for the 10 concurrent sessions over 300 seconds (5 minutes) while using one of the above conferencing applications. The blue line is the total downstream usage, and the orange line is total upstream usage. Note that the total upstream usage stays around 2.5 Mbps which may be a result of running 10 concurrent sessions. Also, the downstream usage stays, on average, around 15 mbps, which leaves roughly 35 Mbps of downstream headroom for other services such as streaming video that can also use the broadband connection at the same time.
Figure 2 shows the upstream bandwidth usage of the 10 concurrent sessions and it appears that these individual sessions are competing amongst themselves for upstream bandwidth. However, all upstream sessions typically stay well below 0.5 Mbps -- these streams are all independent, with the amount of upstream bandwidth usage fluctuating over time.
Figure 3 shows the downstream bandwidth usage for the 10 individual conference sessions. Each conference session typically uses between 1 to 2 Mbps. As previously observed with this application, there are short periods of time when some of the sessions use more downstream bandwidth than the typical 1 to 2 Mbps.
Conferencing Application: B
Figure 4 shows access network usage for 10 concurrent sessions over 300 seconds (5 minutes) for the second conferencing application tested. The blue line is the total downstream usage, and the orange line is total upstream usage. Note that the total upstream usage hovers around 3.5 Mbps. The total downstream usage is very tight, right above 10 Mbps.
Figure 5 shows the upstream bandwidth usage of the 10 individual conference sessions where all but one session is well below 1 Mbps and that one session is right at 2 Mbps. We don’t have an explanation for why that blue session is so much higher than the others, but it falls well within the available upstream bandwidth.
Figure 6 shows the downstream bandwidth usage for the 10 individual conference sessions clusters consistently around 1 Mbps.
Conferencing Application: C
Figure 7 shows access network usage for the 10 concurrent sessions over 300 seconds (5 minutes) for the third application tested. The blue line is the total downstream usage, and the orange line is total upstream usage. Note that the total upstream usage hovers right at 3 Mbps over the 5 minutes.
Figure 8 shows the upstream bandwidth usage of the 10 individual conference sessions where all stay well below 1 Mbps.
Figure 9 shows the downstream bandwidth usage for the 10 individual conference sessions. These sessions appear to track each other very closely around 2 Mbps, which matches Figure 7 showing aggregate downstream usage around 20 Mbps.
Conference Application: D
Figure 10 shows access network usage for the 10 concurrent sessions over 300 seconds (5 minutes) for the fourth application tested. The blue line is the total downstream usage, and the orange line is total upstream usage. Note that the total upstream usage hovers right at 5 Mbps over the 5 minutes, and there is no visible degradation to the conferencing sessions was observed.
Figure 11 shows the upstream bandwidth usage of the 10 individual conference sessions, where there is some variability in bandwidth consumed per session. One session (red) consistently uses more upstream bandwidth than the other sessions but remained well below the available upstream bandwidth.
Figure 12 shows the downstream bandwidth usage for the 10 individual conference sessions. These sessions show two groups, with one group using less than 1 Mbps of bandwidth and the second group using consistently between 2 Mbps and 4 Mbps of bandwidth.
Running All Four Conference Applications Simultaneously
In this section, we examine the bandwidth usage of all four conferencing applications running simultaneously. The test consists of three concurrent sessions from two of the applications and two concurrent sessions from the other two applications (once again a total of 10 conference sessions running simultaneously). The goal is to observe how the applications may interact in the scenario where members of the same household are using different conference applications at the same time.
Figure 13 shows access network usage for these 10 concurrent sessions over 300 seconds (5 minutes). The blue line is the total downstream usage, and the orange line is total upstream usage. Note that the total upstream usage once again hovers around 5 Mbps without any visible degradation to the conferencing sessions, and the downstream usage is pretty tight right above 10 Mbps.
Figure 14 shows the upstream bandwidth usage of the 10 individual conference sessions where several distinct groupings of sessions are visible. There were 4 different apps running concurrently. One session (red) consumes the most upstream bandwidth at averaging around 2 Mbps, whereas the other sessions use less, and some much less.
Figure 15 shows the downstream bandwidth usage for the 10 individual conference sessions across the four apps and, again, there are different clusters of sessions. Each of the four apps are following their own algorithms.
In summary, with a 50/5 broadband service, each of the video-conferencing applications supported at least 10 concurrent sessions, both when using a single conferencing application and when using a mix of these four applications. In all cases, the quality of the 10 concurrent sessions was good and consistent throughout. The 5 Mbps of nominal upstream bandwidth was sufficient to support the conferencing sessions without visible degradation, and there was more than sufficient available downstream bandwidth to run other common applications, such as video streaming and web browsing, concurrently with the 10 conferencing sessions.
DAA 101: A Flexible Approach to Better, Faster Cable Networks
This month, we’d like to share information about Distributed Access Architecture (DAA) and how cable operators are using it to build the 10G networks of the future. In our previous posts about DOCSIS® and Coherent Optics technologies, we touched on some of the components of the cable hybrid fiber-coax (HFC) network, such as the headend and fiber nodes, but of course, there’s much more to it. Today, we’ll take a closer look at the functionality of the cable access network and how it can be distributed between various components to optimize network performance.
What Is Distributed Access Architecture?
DAA isn’t a single technology but rather an umbrella term that describes the network architecture cable operators use to future-proof their access networks. This network evolution involves moving various key network functions that are traditionally located at the cable operator’s hub site (or headend) closer to customers’ homes—while also leveraging signal-quality improvements inherent with digital optics and the ubiquity of Ethernet. In addition, closer is better because it reduces the amount of hardware at the headend and creates efficiencies in network speed, reliability, latency and security.
In a nutshell, CableLabs’ DAA technology solutions give cable operators the ability to cost-efficiently redesign their access networks in stages, when and how they see fit. Because all providers’ business objectives are different, CableLabs has designed several DAA approaches they can leverage. Ultimately, it’s all about building a robust 10G network that not only supports the needs of today’s gig consumers but also anticipates tomorrow’s high-rate applications such as holodecks, artificial intelligence (AI), virtual reality (VR) and more.
Let’s take a look at one particular embodiment of DAA, known as Distributed CCAP Architecture (DCA).
How Does Distributed CCAP Architecture Work?
In a traditional HFC network architecture, the operator’s hub—or headend—is connected via fiber to the fiber node in your geographical region. In the fiber node, the optical signal is converted to a radio frequency (RF) signal that travels via a coaxial cable to the cable modem in your home. The key functions responsible for the transmission of data and device access are placed at either end of the operator’s access network—the hub and the modem—like bookends.
In 2015, CableLabs figured out how to split the key DOCSIS network functions into two components: a Media Access Control (MAC) layer that’s responsible for how devices in a network gain access to the network, and a Physical (PHY) layer, a physical component that’s responsible for the transmission and reception of data. Decoupled, these components can now be partially or fully moved from the headend into a fiber node closer to subscribers’ homes, resulting in increased network capacity, greater speeds, lower latency and so on. That’s the basis for DCA.
How Can Distributed CCAP Architecture Help Build Better Networks?
Distributing key DOCSIS network functions out of the headend and closer to subscribers’ homes comes with many benefits. Primarily, it allows operators to:
- Maximize Their Network’s Potential
DCA allows cable operators to take full advantage of the gigabit capabilities of Coherent Optics and DOCSIS 3.1 technology, including Full Duplex DOCSIS and Low Latency DOCSIS. This means their networks will have more than enough bandwidth to support the latest-generation products for years to come.
- Achieve a Better-Quality RF Signal
With distributed architecture, the RF signal that usually originates in the regional hub can now originate in the optical node, closer to the subscriber’s home, thus reducing distortion and creating a more seamless user experience.
- Increase Network Reliability
Because the main functions of the network no longer need to be housed at the headend, the access network can be redesigned so that fewer homes are connected to any single optical node (where the fiber and coax portions of the network meet). This means that if there’s an outage, it will affect fewer customers, ultimately increasing the reliability of the overall network.
- Expand RF Spectrum in the Future
Because DCA solutions are easily customizable and budget-friendly, they provide new opportunities for cable operators to expand their RF spectrum (basically maximizing the capacity of the coax portion of the HFC network) to support future services.
How Does This Technology Affect Me and My Future?
Widespread adoption of DCA, and importantly the superset of capabilities provided by DAA, is essential to creating the 10G future that we’re all looking forward to. And although it might seem that DAA only provides cost-effective solutions for cable companies, ultimately the real beneficiary is you, the customer. By reimagining and reinventing cable access infrastructure, we’re finding greater efficiencies that translate into more powerful networks. These networks will enable a wave of new, innovative services that will transform the way we live, learn, work and play.
Just like DOCSIS technology, Coherent Optics and other technologies that we’ll be covering in our 101 series, DAA is another piece of the puzzle responsible for propelling cable’s HFC networks into the new decade and beyond. Stay tuned for another installment—coming soon!
CableLabs’ Latest Advancements on the Path to 10G
At CableLabs, staying at home during the COVID-19 pandemic has resulted in new ways of collaborating that have helped us continue to build technologies that will deliver internet speeds 10 times faster than today’s networks. The trek to 10G started in 2019, as we began working with our members to create the technologies that build the 10G network.
This week, we announced significant advancements made in 2020 toward the realization of 10G. A sampling of our technical achievements over this past year includes DOCSIS® 4.0 technology, Intelligent Wireless Network Steering (IWiNS), Flexible MAC Architecture specifications, our leadership in the development of the IEEE 802.3ca standard and increased Wi-Fi reliability and performance. Plus, some of our members have started testing and delivering 1.25 Gbps service.
Our digital future will stall without a platform that can meet our needs. Although we don’t know what the next trend will be, we do know that the Internet will be central to its development. By advancing device and network performance to stay ahead of consumer demand, 10G will provide myriad new immersive digital experiences and other emerging technologies that will revolutionize our lives.
It’s a new year, and we’re hyper-motivated to continue working on advancements in network reliability, security, speed and latency. Check out this chart to see how the latest 10G achievements map to these four areas.
IWiNS—An Informed Approach to Mobile Traffic Steering
It’s 3p.m. and you’re rushing, in between meetings, to pick up your kids from school. You start to pull out of your garage when your boss texts you to hop on a quick video call. But something doesn’t work. Your app seems stuck, showing a spinning wheel—and you really need to get going. You’re starting to get nervous. You shake your fist at the sky and shout, “The Wi-Fi!”
That’s right: You’re far enough away from your home Wi-Fi access point that you have very little connectivity available, but you’re still close enough that your phone won’t let go of that connection. It happens all the time—like the last time you were in that coffee shop, browsing the web just fine, but then you suddenly had issues joining a video call. Or when you were walking your dog around the neighborhood while playing your favorite game, and the session kept freezing and crashing.
So, what do you do when you’re paused in your driveway, eager to get on the road? You rush through your phone settings, turn off Wi-Fi, your cellular connection kicks in and now you can finally start the video call with your boss. Your intuition saved the day—this time!
The good news is that there’s likely nothing wrong with your home Wi-Fi or your phone and that you aren’t alone in this experience. In fact, CableLabs’ primary research shows that whenever mobile customers perceive a poor quality of experience, 64 percent of them feel the need to manually troubleshoot their network connectivity—and they believe the quickest and most effective solution is to turn off Wi-Fi and rely solely on the cellular network. Unfortunately, this behavior causes operators direct and indirect losses, and it prevents users from leveraging operator Wi-Fi networks that could serve them better and potentially give them a better mobile user experience.
We live in a constantly connected world in which users often have overlapping Wi-Fi, LTE and Citizens Broadband Radio Service (CBRS) coverage. Manually troubleshooting network connectivity frustrates users who don’t want to be concerned about where their data is coming from. How can operators improve the customer experience while maintaining control over how network resources are utilized?
A 2018 PWC Consumer Intelligence Series 5G Survey shows that “roughly one-third [of broadband customers surveyed] said that reliability was a ‘must-have’ for internet access” and that “performance drops were a stronger concern than any other factor, though security, speed and cost efficiency each came up as important.”
As part of our commitment to 10G, CableLabs has been working tirelessly to develop new technologies that help improve latency, security, speed and reliability for broadband customers around the globe. With the importance of reliability to the end-consumer in mind, improvements to connection reliability both in the home and in the mobile space have become one of the top objectives of the 10G platform.
In 2018, CableLabs started researching technologies to improve reliability within the mobile user experience. We analyzed several standard and proprietary solutions, and we identified gaps representing great innovation opportunities. That was the inception of the Intelligent Wireless Network Steering (IWiNS ) project, a mobile traffic steering technology created by CableLabs. IWiNS enhances the mobile user experience by adding network and application awareness to traditional mobile traffic steering without requiring any changes to the mobile device or the network infrastructure.
Previous and current mobile steering solutions are divided into two main categories: network-centric and user-centric solutions:
- Network-centric solutions such as LTE-WLAN aggregation (LWA), LTE-WLAN Radio Level Integration with IPsec Tunnel (LWIP), 5G Access Traffic Steering Switching and Splitting (ATSSS) are generally standardized by 3GPP and are centered around the cellular ecosystem. They treat a secondary external network asset (e.g., a Wi-Fi access point) as subordinated upon a cellular base station and core network. These solutions require support inside the mobile device and modifications to Wi-Fi access points.
- User-centric solutions are based on downloadable over-the-top apps that aggregate throughput across all the wireless networks that a device can connect with. Although these solutions don’t require specific support from the device operating system (or modifications to the network infrastructure), they provide little or no control for the operator to manage the configuration of the traffic steering rules.
IWiNS fills the gaps for both types of solutions by building a technology that takes advantage of an over-the-top approach and gives full control of the traffic steering configuration to operators. Operators can now optimize single-user connectivity and take advantage of a crowd-sourced approach, resulting in a more reliable, efficient and adaptive traffic steering solution. It’s like evolving from paper maps (static and unilateral information) to the wonders of online navigation, where the power of crowd-sourced information is available.
With IWiNS, operators can generate per-application policies that are optimized using real-time network performance indicators derived from all users connected to the network. Users’ experience is enhanced by freeing them from manually troubleshooting network-connectivity issues, allowing operators to take advantage of a flexible toolset to dynamically manage network resources. Mobile virtual network operators (MVNOs) can cut costs by increasing Wi-Fi offload. Mobile network operators (MNOs) can reduce the capital cost of serving dense demand areas, leveraging cheaper network infrastructure assets and turning multiple networks into one.
IWiNS is deployed by using a client-server architecture in which the client is installed on the mobile device as an over-the-top mobile app and the server is hosted anywhere that’s convenient for the operator (e.g., public cloud, on-premises cloud, private data center). IWiNS doesn’t require any modification to the mobile device operating system or to the network infrastructure. The IWiNS client can also be embedded inside the operator’s customer care app, making its deployment simpler for the operators. The server is composed of containers that handle policy management, network metrics collection and performance estimation functions—all orchestrated to ensure the scalability, efficiency and security of the deployment.
IWiNS optimizes the mobile user experience in real time and also gives operators an effective tool to shape network utilization and control their costs. With IWiNS, a new way of experiencing mobile connectivity is right around the corner.
CableLabs has created and demonstrated the IWiNS 1.0 proof of concept. More information about the IWiNS project, including a white paper, demo and executive summary, is available below.
2021 Tech Innovation Predictions
Now that 2021 has arrived, it’s time to share my tech innovation predictions for the year. Watch the video below to find out what you can expect to see this year.
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Best of 2020: The Cable Industry’s Proudest Achievements with CableLabs
Unlike any year in recent memory, 2020 has scrambled our way of life, changing how we communicate, how we work and even where we go—on a global scale. At CableLabs, meetings were rescheduled, new rules were drawn up and enacted, and events were put on hold or went virtual. And still—despite the numerous logistical, psychological and practical challenges presented by the COVID-19 pandemic—the industry learned new ways to collaborate with everyone. We all continued to work toward a brighter future, even snagging a few industry awards along the way. In the spirit of the holidays, let’s end the year on a high note by remembering only the best of 2020. We’ve got quite a few proud moments to share!
An incredible achievement on our road to 10G, Mediacom’s 10G Smart Home is the first demonstration of 10G in action. It’s essentially a working technology laboratory disguised as an ordinary home—except this future home is anything but ordinary! It’s wired for ultra-fast speeds that allow us to test the latest “smart home” technologies, including Internet of Things (IoT) kitchen devices, telemedicine connections, home automation, immersive entertainment, VR/AR applications and much more—in a real-life environment. A true tech paradise of the future!
CableLabs published the DOCSIS 4.0 specification
In March 2020, we announced the release of the DOCSIS® 4.0 specification, which incorporates both full-duplex and extended-spectrum capabilities. It doubles downstream speeds to 10 Gbps and quadruples upstream speeds to 6 Gbps—another big milestone on the path to 10G.
CableLabs published the Flexible MAC Architecture (FMA) specification
This release is the culmination of thousands of hours of work across the cable industry. Part of the 10G toolset, FMA defines the standardization of the complete disaggregation of Converged Cable Access Platform (CCAP) management and the control and data planes to support cable operators’ next-generation data services. In non-technical terms, FMA brings us much closer to making 10G a reality in the near future.
At the beginning of December 2020, SCTE members voted to make the Society of Cable Telecommunications Engineers (SCTE) and its global arm, the International Society of Broadband Experts (ISBE), a subsidiary of CableLabs. The decision will become effective January 1, 2021. Working together to closely manage our innovation, specifications, standards and training and deployment efforts, these entities can drive faster and more cost-effective infrastructure upgrades in the industry.
CableLabs in the News
CableLabs won an Emmy award
Earlier this year, CableLabs won its second Technology and Engineering Emmy Award—this time for enabling the development and deployment of the hybrid fiber-coax (HFC) network architecture. HFC is a revolutionary suite of technologies responsible for the razor-sharp broadband video and high-speed Internet you enjoy today. It’s also the basis for the cable industry’s 10G platform, which will usher in a new era of super-high-speed, low-latency innovations.
Lori Lantz became a CableFax Most Powerful Women honoree
CableLabs’ SVP and Chief People Officer, Lori Lantz, has been instrumental to the company’s success. Over the past 12 months, she has championed numerous high-impact leadership development programs aimed at strengthening senior leadership abilities and strategic recruiting efforts. Lantz is always laser-focused on identifying areas of improvement that benefit individual team members as well as the company as a whole. The CableFax recognition is well deserved for her tireless efforts to shape our world-class organization.
Ike Elliott stepped into his new role as president and CEO of Kyrio
After a decade of leading the CableLabs Strategy Team, Ike Elliott has transitioned into his new role as president and CEO of Kyrio, a CableLabs subsidiary that provides broadband device testing, security analysis and software services for the connectivity industry. It’s an exciting move that will allow him to channel his vast CableLabs experience into expanding the impact of state-of-the-art broadband technologies at Kyrio. Congratulations, Ike!
Dr. Jennifer Andreoli-Fang named the 2020 WICT Walk of Fame Woman in Technology
In May 2020, our distinguished technologist, Dr. Jennifer Andreoli-Fang, received the prestigious Woman in Technology award for her contributions to the cable industry. A relentless innovator with more than 100 granted and filed patents, Andreoli-Fang has spent the past 13 years leading the development of game-changing technologies such as DOCSIS® 3.0 MAC, DOCSIS 3.1 MAC, Full Duplex DOCSIS MAC architecture, unlicensed LTE and NR, mobile xhaul and many more. We’re honored to have Andreoli-Fang as a member of the CableLabs family.
Phil McKinney joined Multichannel News’ “The Watch List”
Our CEO and innovation guru, Phil McKinney, is included in Multichannel News’ “The Watch List”—a new feature that ranks the 25 most influential insiders who define and drive the strategies and successes of the TV industry. Not surprisingly, McKinney has made the top 10 list. You can check out his profile in all Multichannel News publications.
This is only a small sample of the industry’s and our team’s accomplishments this year. From technology to strategy, we overcame unforeseen challenges and continued to deliver results that we can all be proud of. We look forward to bringing renewed, positive energy into 2021 as we continue to innovate the future.
CableLabs would like to thank its industry colleagues for their hard and dedicated work. We wish everyone a very happy and healthy New Year!
10G: Enhancing the Power of Human Connection
If 2020 has taught us anything, it’s that connectivity is essential to our wellbeing and happiness. It fosters a sense of belonging—whether it’s to our family, our school, our company or just a random group of like-minded souls. And it’s not so much about the internet or the devices we use—it’s about experiences and staying connected to what matters most. That’s the ultimate goal of 10G.
In the last three decades, cable connection speeds increased from 9600 bps to 1 gig—now available to over 80% of U.S. homes! This has transformed our lives, giving us unparalleled access to the information we need, restructuring the way we conduct our businesses and communicate with others, anytime, anywhere around the world. And still, we’re nowhere near maximizing our networks’ potential. In the near future, 10G networks that are up to 100 times faster than what we have today will open doors to a whole new era of innovation, including autonomous vehicle fleets, holographic media, in-home telehealth solutions, immersive entertainment experiences and much more.
What will that mean for us? Will the seamless inner workings of our networks and smart devices help us lead healthier, happier and more fulfilling lives? Will this technology be able to take care of mundane and time-consuming tasks so we can focus on ourselves and our loved ones? We bet it will! We are now standing on the brink of an exciting new frontier, powered by super-fast, reliable and secure HFC networks.
To see more about what this means for changing people’s connected lives, check out this video:
A Warm Welcome to SCTE•ISBE—Now Joined With CableLabs!
Today, SCTE•ISBE members voted to make Society of Cable Telecommunications Engineers (SCTE) and its global arm, the International Society of Broadband Experts (ISBE), a subsidiary of CableLabs. The agreement is the result of a unanimous vote of the CableLabs and SCTE board of directors and a vote of overwhelming support for the proposal by SCTE members. This combination will increase the alignment of investment, resources and innovations between the two organizations. CableLabs members can expect expanded benefits as part of the transaction, which goes into effect January 1, 2021.
This strategic decision allows SCTE•ISBE and CableLabs to increase industry collaboration and accelerate our progress toward 10G by streamlining the cable technology innovation cycle—from the very early research and ideation stage all the way to mass market deployment.
SCTE•ISBE has served as a cable thought leader for over 50 years, bringing the industry together through various initiatives such as its incredibly successful annual SCTE•ISBE Cable-Tec Expo®, core learning and development programs for cable technologists and other membership activities. SCTE’s goals of facilitating productive industry partnerships, technological progress and innovation are already very closely aligned with ours. By formally combining our efforts and expertise, we aim to further accelerate our innovation and deployment efforts—a mutually-beneficial move for all our respective members and the global cable industry as a whole.
The decision to join forces is not only smart, it is also very timely. The current pace of innovation requires us to move quicker than ever before. After all, we are building the communication platform that will become a cornerstone of future technological progress. By syncing and closely managing our innovation, specifications, standards, training and deployment efforts between our two companies, the industry can drive faster and more cost-effective infrastructure upgrades. These efficiencies will allow for smoother workflows and more collaboration opportunities among our members and the cable community.
Together we can more efficiently test, build and deploy technologies that will meet and exceed the needs of cable broadband customers around the world, as well as allow our members and vendors to maximize their investments and resources. We are here to support our cable community on all fronts—from education and training to technical expertise and industry standardization efforts, plus, much more. This is why we are very much looking forward to welcoming SCTE•ISBE to our CableLabs family in 2021!
Latency 101: Getting From There to Here
Welcome back, once again, to the CableLabs 101 series! In our most recent post, we discussed the fiber portion of the hybrid fiber-coax (HFC) network, as well as the coherent optics technology that’s widely considered to be the hyper-capacity future of internet connectivity. Today, we’ll focus on a topic of growing importance for many of the new applications in development—a topic that significantly impacts the user experience even if it’s not well known. That topic is latency.
What Is Latency?
Simply put, latency means delay.
In our post about coherent optics technology, we pointed out how quickly light can travel through a piece of fiber-optic cable: an astonishing 128,000 miles per second. However, as incredibly fast as that is, it still takes time for light to carry information from one point to another.
Imagine for a moment that you’re reading this blog post on a computer in New York City. That would mean you’re about 1,600 miles away from the CableLabs offices here in Colorado. If we assume that the entire network between you and our offices is made of fiber (which is close enough to true for our purposes), it would take a minimum of 0.0125 seconds—or 12.5 milliseconds (12.5 ms)—for the text to travel from our server to your computer.
That’s not a lot of time, but distance is not the only source of delay—and those delays can add up.
For example, to read this post, you had to click a link to view it. When you clicked that link, your computer sent a request to our server asking for the article. That request had to travel all the way to Colorado, which also took the same minimum of 12.5 ms. If you put the two times together, you get a round-trip time (the time it takes to go somewhere and back), which in our case would be a minimum of 25 ms. That’s a longer amount of time, but it’s still pretty small.
Of course, the server can’t respond instantly to your request. It takes a moment for it to respond and provide the correct information. That adds delay as well.
In addition, these messages have to traverse the internet, which is made up of an immense number of network links. Those network links are connected by a router, which routes traffic between those links. Each message has to hop from router to router, using the Internet Protocol to find its way to the correct destination. Some of those network links will be very busy, and others won’t; some will be very fast, and some might be slower. But each hop adds a bit more delay, which can ultimately add up and become noticeable—something you might refer to as lag.
Let’s try a little experiment to illustrate what we’re talking about.
If you’re on a Windows computer, select Start, Programs, Accessories, Command Prompt. Doing so will open up a window in which you can type commands.
First, try typing the following: ping www.google.com
After you hit Enter, you should see some lines of text. At the end of each line will be a “time” in milliseconds (ms). That’s the amount of time it took for a ping request to get from your computer to Google’s server and for a response to come back, or the round-trip latency. Each value is likely different. That’s because each time a ping (or any message) is sent, it has to wait a small but variable amount of time in each router before it’s sent to the next router. This “queuing delay” accumulates hop-by-hop and is caused by your ping message waiting in line with messages from other users that are traversing that same part of the internet.
Next, try typing the following: tracert www.google.com
You should see more lines of text. The first column will show a hop number (the number of hops away that point is), the next three will show times in milliseconds (since it checks the latency three times) and the final column will show the name or the address of the router that’s sending you the message. That will show you the path your request took to get from you to the Google server. You’ll notice that even as close as it is (and as low as your latency might be), it had to hop across a number of routers to get to its destination. That’s how the internet works.
(Note that you might have some fields show up as an asterisk [*]. That’s not a problem. It simply means that the specific device is configured not to respond to those messages.)
If you’re on a Mac, you can do the same thing without needing a command prompt: Just search for an application on your computer called Network Utility. To send a ping in that app, click on the Ping tab, type in www.google.com and click the Ping button. Similarly, to check the route, click on the Traceroute tab, type in the same website name and click the Trace button.
What Is Low Latency?
A term you might have heard is low latency. This term has been getting more and more attention lately. In fact, the mobile industry is touting it as an essential aspect of 5G. But what exactly is low latency, and how does it relate to our definition of latency?
The reality is that there’s no formal definition of what qualifies as low latency. In essence, it simply means that latency is lower than it used to be, or that it’s low enough for a particular application. For example, if you’re watching a streaming video, low latency might mean having the video start in less than a second rather than multiple seconds.
However, if you’re playing an online game (or perhaps using a cloud gaming service), you need the latency to be low enough so that you don’t notice a delay between moving your controller and seeing the resulting movement on your screen. Experiments have shown that anything above about 40ms is easily noticeable, so low latency, in this case, might mean something even lower than that.
How Do We Achieve Low Latency?
Reducing latency requires us to look at the sources of latency and try to figure out ways to reduce it. This can include smarter ways to manage congestion (which can reduce the “queuing delay”) and even changing the way today’s network protocols work.
Reducing latency on cable networks is something CableLabs has been working on for many years—long before it became a talking point for 5G—and we’re always coming up with new innovations to reduce latency and improve network performance. The most recent of these efforts are Low Latency DOCSIS, which can reduce latency for real-time applications such as online gaming and video conferencing, and Low Latency Xhaul, which reduces latency when a DOCSIS network is used to carry mobile traffic.
How Does Low Latency Affect Me and My Future?
Achieving low latency opens the door to do things in near real-time: to talk to friends and family as if they were close by, to interact in online worlds without delays and to simply make online experiences quicker and better. In the long term, when combined with the higher-capacity networks currently in development, low latency opens the door to new technologies like immersive interactive VR experiences and other applications that have not been invented yet.
The future looks fast and fun.
Coherent Optics 101: Coming at You at 0.69c
Welcome back to the CableLabs 101 series! In our previous post, we discussed the basic components of a typical hybrid fiber-coax (HFC) cable network infrastructure and the role of DOCSIS® technology in data transmission over the coaxial portion of the network. Today, we’ll focus on the fiber portion of the HFC network, as well as the coherent optics technology that’s widely considered to be the hyper-capacity future of internet connectivity.
What Is Coherent Optics Technology?
Cable’s HFC networks are “fiber-rich,” which means they’re composed mostly of fiber—a bundle of very thin, hair-like strands of glass or plastic wire. Fiber is light, durable, and most importantly, capable of transmitting a lot of data over very long distances incredibly quickly. Light travels through a vacuum at 186,282 miles per second, a universal constant that scientists denote as “c.” Although light traveling through fiber optic cable moves a little slower than that (69 percent of the speed of light in a vacuum, or 0.69c), it’s still incredibly fast at over 128,000 miles per second. That’s fast enough for a single burst of light to circle the earth more than five times in a single second.
Until recently, signals in a typical HFC network were transmitted over fiber using analog technologies: an electrical radio frequency signal would be converted to an analog optical signal, transmitted over fiber optic cables, and then converted back to an electrical signal at the fiber node. With the advent of Distributed Access Architecture technologies, which will help cable operators cost-effectively add more capacity to their networks, that same fiber is being re-used to carry digital signals rather than analog ones.
The digital fiber technology being deployed today in access networks uses an “on-off keying” approach, in which a transmitter rapidly turns the laser on and off to send a signal; each pulse can signal a single bit of digital information (a 1 or a 0). Coherent optics adds further dimensions to the optical signal to carry more information simultaneously: rather than just pulsing the light on and off, it uses other properties of light (e.g., amplitude, phase and polarization) to carry multiple bits with each burst of information rather than just one bit. That can increase the data-carrying capacity of a single fiber by as much as 70 times, compared with non-coherent technology.
How Has This Technology Evolved?
Coherent optics technology is not new. It’s been used for over 10 years in long-haul fiber networks that span thousands of miles between cities and countries. More recently, as the cost of coherent optics technology has come down and speeds have gone up (from forty to now hundreds of gigabits per second) it has seen growing deployment in metropolitan or regional networks. The one remaining frontier has been the access network—such as in a cable HFC network, which has a large number of relatively short links, requiring a very low-cost solution.
It was for this reason that CableLabs embarked on an effort to define the use of coherent optics for cable access networks: to define requirements specific to access networks, thereby promoting interoperability, scale and competition. All this reduces the cost of this technology to the point at which it could be used widely to grow the capacity of cable operator fiber networks.
This vision was realized with the publication of our initial Point-to-Point (P2P) Coherent Optics specifications (released in June 2018), which defined how to send 100 Gigabits per second (Gbps) on a single wavelength, and how to send up to 48 wavelengths on a single fiber. That was followed by our version 2 specifications (released in March 2019), which defined interoperable operations at 200 Gbps per wavelength, doubling the capacity of the network. And both specifications included support for another key technology called Full Duplex Coherent Optics, which doubles the capacity of each fiber yet again while enabling the cost-effective use of a single fiber rather than the normal fiber pair.
How Does This Technology Affect Me and My Future?
When you think about current technology trends and predictions for the future, you’ll notice a common thread. Future innovations—like holograms, 360° virtual reality (VR), artificial intelligence and so on—will all require super high-capacity, low-latency networks that can transmit a ton of data very, very quickly. We’re not talking about just long-haul networks between cities and countries, but everywhere.
This is why cable companies started investing in the expansion of their fiber infrastructure and fiber optic technology decades ago. By focusing on “fiber deep” architectures—a fancy term for bringing fiber closer to subscribers’ homes—and using technologies such as coherent optics to mine even more bandwidth out of the fiber that we already have in the ground today, we can ensure that our cable networks continue meeting the requirements of current and future innovations. Thanks to those efforts, you’ll be able to one day enjoy your VR chats in “Paris,” work in a “holo-room” and much, much more.