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HFC Network

Testing Bandwidth Usage of Popular Video Conferencing Applications

Jay Zhu
Senior Engineer

Nov 5, 2020

This year we have seen a shift toward working and learning from home and relying more on our broadband connection. Specifically, most of us use video conferencing for work, school and everyday communications. With that in mind, we looked at how much video conferencing a broadband connection can support.

In the U.S., the Federal Communications Commission (FCC) defines broadband to be a minimum of 25 Mbps downstream and 3 Mbps upstream. So, we started there. The investigation looked at how many simultaneous conferencing sessions can be supported on the access network using popular software including Google Meet, GoToMeeting, and Zoom. The data gathering used typical settings and looked at both upstream and downstream bandwidth usage from and to laptops connected by ethernet cable to a modem connected to a wired broadband connection. To avoid any appearance of endorsement of a particular conferencing application, we have not labeled the figures below with the specific apps under test.

Since this is CableLabs, we used DOCSIS® cable broadband technology. A Technicolor TC8305c gateway was used, which is a DOCSIS 3.0 modem supporting 8 downstream channels and 4 upstream channels. Note that this modem is several years old and not the current DOCSIS 3.1 technology. The modem was connected through the cable access network to a CommScope E6000 cable modem termination system (CMTS).

Laptops used ethernet wired connections to the modem to ensure no variables outside the control of the service provider would impact the speeds delivered, and conferences were set up and parameters varied while traffic flow rates were collected over time. Various laptops were used, running Windows, MacOS and Ubuntu – nothing special, just laptops that were around the lab and available for use.

Most broadband providers over-provision the broadband speeds delivered to customers’ homes – this is for assorted reasons including considering protocol overhead and ensuring headroom in the system to handle unexpected loads. For this testing, the 25/3 service was over-provisioned by 25%, a typical configuration for this service tier.

At a high level, we found that all three conferencing solutions could support at least five concurrent sessions on five separate laptops connected to the same cable modem with the above 25/3 broadband service and with all sessions in gallery view. The quality of all five sessions was good and consistent throughout, with no jitter, choppiness, artifacts, or other defects noticed during the sessions.

This research doesn’t take into account the potential external factors that can affect Internet performance in the home, from the placement of Wi-Fi routers, 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 25/3 broadband.

The data is presented below where samples were collected every 200 milliseconds using tshark (the Wireshark network analyzer).

Conferencing Application: A

The chart below (Figure 1) shows access network usage for the five concurrent sessions over 300 seconds (five minutes) for 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 upstream usage stays below 2 Mbps over the five minutes.

Figure 2 shows the upstream bandwidth usage of the five individual conference sessions where each is below 0.5 Mbps.

Figure 3 shows the downstream bandwidth usage for the five individual conference sessions.

Conferencing Application: B

Figure 4 shows access network usage for five concurrent sessions over 300 seconds (five minutes) for the next conferencing application tested. The blue line is the total downstream usage, and the orange line is total upstream usage. Note that the upstream usage hovers around 3 Mbps as each conference session attempts to use as much upstream bandwidth as possible.

Figure 5 shows the upstream bandwidth usage of the five individual conference sessions where each is below 1 Mbps, though the individual sessions sawtooth up and down as the individual conference sessions compete for more bandwidth. This is normal behavior for applications of this type, and did not have a negative impact on stream quality.

Figure 6 shows the downstream bandwidth usage for the five individual conference sessions.

Conferencing Application: C

Figure 7 shows access network usage for the five concurrent sessions over 300 seconds (five minutes) for the third of the applications 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 Mbps over the five minutes.

Figure 8 shows the upstream bandwidth usage of the five individual conference sessions where each is below 1 Mbps, though the individual sessions sawtooth up and down as the individual conference sessions compete for more bandwidth. This is normal behavior for applications of this type, and did not have a negative impact on stream quality.

Figure 9 shows the downstream bandwidth usage for the five individual conference sessions. Note the scale of this diagram is different because of higher downstream bandwidth usage.

In summary, each of the video conferencing applications supported at least five concurrent sessions over the 25/3 broadband connection. The focus of this analysis is upstream bandwidth usage, and all three video conferencing technologies manage the upstream usage to fit within the provisioned 3 Mbps broadband speed. For at least two of the conferencing applications, there was also sufficient available downstream speed to run other common applications, such as video streaming and web browsing, concurrently with the five conferencing sessions.

Areas of Future Study

Conferencing services have enhanced modes that allow for higher definition video but that also uses more bandwidth. These modes place additional load on the broadband connection and may reduce the number of simultaneous conferences.

An interesting finding is that upstream bandwidth usage out of a home can depend on how other conference participants choose to view the video. Gallery mode uses lower bit rate thumbnail pictures of participants and is the most efficient for a conference. “Pinning” a speaker’s video can cause higher bandwidth out of a home. In addition, users that purchase add-on cameras that provide higher definition video than the camera included with their laptop may see higher upstream usage.

Learn More About Broadband Network Performance

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Wireless

  Inform[ED]™ Wireless Tackles Spectrum Policy with FCC Commissioners

Rob Alderfer
VP, Technology Policy

Jun 1, 2016

Last month in New York, CableLabs hosted its inaugural Inform[ED] Wireless conference, where we gathered leaders and luminaries to chart the evolution of wireless networks. Consumers’ appetite for wireless continues to grow, and fixed networks - like cable and its Wi-Fi assets - become ever more important to satisfying their needs.

The program was holistic, touching on business strategy, technology, and of course policy, which is fundamental to the future of wireless. Spectrum is the key enabler of our wireless future, and we were fortunate to hear what the FCC has in store from Commissioners Jessica Rosenworcel and Michael O’Reilly, in a conversation facilitated by NCTA Executive Vice President James Assey.

Unlicensed Spectrum, Past and Future

Commissioner Rosenworcel began by grounding the group in some history, noting that Wi-Fi as we know and love it today is, essentially, a happy policy accident. In liberalizing the 2.4 GHz frequency band for wider unlicensed uses in the 1980s, the FCC could not imagine the industry-driven innovation that would take place in what were then considered ‘junk bands’.

Now that Wi-Fi has become consumers’ on-ramp to digital opportunity, the FCC is much more intentionally building on that success. Commissioner O’Reilly noted the substantial opportunity to usher in next-generation gigabit Wi-Fi by opening new bandwidth in the critical 5 GHz frequency band. A portion of 5 GHz is used by Wi-Fi today; by expanding the spectrum available there, consumers would win big through improved broadband speed and capacity.

To make that happen, the FCC is considering how Wi-Fi should share spectrum with another service, known as Dedicated Short Range Communications (DSRC). DSRC received a 5 GHz spectrum allocation in 1999, and is envisioned by the auto industry to provide vehicle-to-vehicle communications. Since it has not yet been deployed, it is the perfect time to determine spectrum sharing regime.

CableLabs has written on this topic, providing the technical foundation for the progress that is possible here, just as we have driven forward Wi-Fi spectrum opportunities previously. Working together, with outspoken leaders like the Commissioners Rosenworcel and O’Reilly, we should be able to turn that possibility of progress on 5 GHz into reality.

Growing the Pie Through Sharing

There are no easy wins in spectrum policy. As demand for wireless grows across sectors and services, sharing the spectrum more efficiently becomes increasingly important. By enabling more dynamic use of the spectrum – particularly in frequencies used by the Federal government, according to Commissioner O’Reilly – we can grow the pie for new uses, instead of trying to carve up smaller, unsatisfying slices.

Commissioner Rosenworcel noted that the FCC is moving forward with an approach that would do just that. In the 3.5 GHz frequency band, new commercial uses will be enabled later this year, which will share the spectrum with U.S. Naval radar systems through a database-driven access architecture. When the Navy isn’t sailing nearby, consumers will be able use the spectrum.

CableLabs is doing research in this area under an experimental license from the FCC. We are also helping to build the all-important access database architecture through the industry body that is leading the effort, known as the WinnForum.

To the Next Frontier

There is much buzz in the industry about ‘5G’ – the next generation of mobile technology – which is likely to use spectrum in higher frequencies than have been typical to date. These are the ‘spectrum frontiers’, where no mobile system has yet ventured, but will be integral to network densification and capacity augmentation, and will drive fixed/mobile convergence.

Commissioners O’Reilly and Rosenworcel both expressed a desire for the US to take a leadership role in 5G development, which the FCC will assist by making new ‘spectrum frontiers’ available – including the 28 GHz, 37 GHz, 39 GHz, and 60 GHz bands – as early as this summer.

Research in this area is progressing apace, and 3GPP, the mobile standards body in which CableLabs participates, is beginning to specify the details of what 5G will look like. But ultimately, progress toward 5G will depend on spectrum availability, in the US and abroad. The International Telecommunications Union is gearing up to address this in 2019. By the sound of it, the FCC will be well down the path toward these new frontiers by then.

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Policy

Approaches to Increasing Wireless Spectrum

Rob Alderfer
VP, Technology Policy

May 13, 2014

At the 2014 Cable Show, one of the hottest topics was Wi-Fi. It doesn’t take long to realize how important access to this suddenly precious resource really is: Studies indicate that the number of wirelessly connected devices will triple by 2020, to a mind-blowing 30 billion devices.

[Related: Wireless Spectrum Infographic]

And with each new device that connects, less space is available in the wireless spectrum. The FCC recently voted to increase usable wireless spectrum in the 5GHz band, but this is a small fraction of what will be needed to support the growing wireless culture.

Spectrum 1

How do we get to a point where there is plenty of spectrum for everyone?  There are multiple approaches.

Reallocating Spectrum

Historically, the government has sought to meet new wireless needs by reallocating spectrum from one service to another. The idea has generally been that each service needs its own exclusive spectrum in order to avoid interference, and as technology changes the FCC needs to shuffle the spectrum portfolio.

For those that can remember all the way back to 2009, the digital television transition was an example of this – the FCC recaptured some spectrum used for TV broadcasts and repurposed it for wireless broadband.  Believe it or not, this process started about 15 years earlier – so reallocation takes time. Not exactly ideal in a world where technology seems to evolve daily.

The FCC already sees new opportunities for further reallocation of TV spectrum to broadband – but hopes to speed it up this time by creating a new two-sided market for spectrum. In essence, they will buy spectrum back from broadcasters in order to put it in the hands of our smartphones and tablets.

The FCC hopes a one-time-only auction will incentivize broadcasters to relinquish licensed spectrum in exchange for presumably very large sums. They get cash in their pocket for giving up space that was under-used, more wireless spectrum is available, and everybody’s happy – right?

Possibly. There are a lot of unknowns at this point. Some questions were answered at the May 15 meeting of the FCC, but not everyone can be happy all of the time. Hopefully things will move faster than the last 15-year process, even if keeping up with wireless growth is a near-impossible task.

Sharing Spectrum

Another approach to meeting wireless demand is to open up new spectrum by sharing it among many services, rather than shifting spectrum from one service to another. This is possible because wireless technology has come a long way. Wi-Fi is a great example – it is a fundamentally “polite” technology, since it listens to the airwaves before it transmits. It was built to share.

Without the need to shift services from one band of spectrum to another, spectrum sharing lends a greater ability to keep up with wireless growth. And since a lot of that growth is occurring over Wi-Fi, that’s a real opportunity. The FCC’s action in March to expand Wi-Fi access to part of the 5 gigahertz (GHz) band is a case in point. And there’s more that can be done in 5 GHz, and in other bands like 3.5 GHz.

But the value of spectrum sharing depends on the specifics. We still need to protect against interference, but we also need to be sure that we’re not overly protective and discourage productive use of the spectrum. We don’t want Wi-Fi jamming military naval radars, for example, but neither do we want Wi-Fi to be confined to Kansas. (No offense to Kansas.)

It’s a balance. And CableLabs is doing the R&D to ensure that the right balance is struck.

Increasing Wi-Fi Spectrum: A Roadmap

Ultimately, it will take a combination of approaches to achieve the national goal of wireless spectrum growth.

slides for James2

When CableLabs helped the FCC with research to increase the 5GHz band, there was a concerted effort around interference issues. This collaborative research will serve as the technology roadmap for interference issues surrounding both reallocation and sharing of Wi-Fi spectrum. It’s critical that spectrum policy moves forward quickly and effectively to benefit everyone who uses it – and that’s all of us.

Rob Alderfer is a Principal Strategic Analyst for CableLabs, where he guides technology policy and strategy across the industry.

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Policy

FCC Votes to Expand Wireless Spectrum: A Win for Wi-Fi

Rob Alderfer
VP, Technology Policy

Mar 31, 2014

Today is a big day for Wi-Fi and everyone that uses it – which is, of course, all of us. Our Wi-Fi is about to get twice as good. How? By doubling the size of the Wi-Fi pipe.

The FCC voted today to double the amount of wireless spectrum that Wi-Fi uses in the 5 gigahertz (GHz) band. That’s 100 megahertz (MHz) of newly useful Wi-Fi bandwidth.

You might have heard of 5 GHz – it's the globally harmonized home for the latest Wi-Fi technology: 802.11ac, also known as “gigabit Wi-Fi” for its incredibly fast broadband speed. 802.11ac is beginning to hit the market in force – the MotoX and latest Samsung Galaxy smartphones, among many other devices, have it already. Pretty soon, 802.11ac will be in just about everything.

The only problem with gigabit Wi-Fi is that regulations prevented it from reaching its full gigabit potential.

Until today.

It has taken a lot of work by many dedicated people to get to this moment. A little over a year ago, the FCC proposed a number of ways to increase Wi-Fi bandwidth. Additional spectrum is needed to support the continued growth of wireless broadband, which we have written about, and is a central feature of the Administration’s technology policy and the National Broadband Plan.

[Related: CableLabs' Work on Wireless Spectrum]

A strong desire to make progress in wireless policy is not enough, however. Success requires attention to detail. In the context of 5 GHz, that means understanding how Wi-Fi can share the airwaves with the other wireless services that use the same spectrum.

That’s where CableLabs comes in. In collaboration with colleagues at the University of Colorado, we developed a sophisticated simulation of potential interference between Wi-Fi and a satellite phone system that uses part of the 5 gigahertz band. This analysis served as the technology framework for today’s FCC action.

“The FCC vote to expand Wi-Fi access in the 5 GHz band is a great step forward for wireless broadband,” said Phil McKinney, president and chief executive officer of CableLabs. “This action substantially increases  Wi-Fi capacity, making gigabit Wi-Fi speeds possible. CableLabs’ insights on spectrum sharing, including sophisticated simulation of how Wi-Fi will interact with other services using the same spectrum, played a key role in helping the FCC move forward.”

Cable operators will put this new bandwidth to good use, along with the rest of the Wi-Fi community. But to be clear, today’s win for Wi-Fi is just the beginning. Regulators in other nations should take note and consider how to fully enable the global gigabit Wi-Fi standard. And the FCC has more work to do as well: Today’s newfound 100 MHz of Wi-Fi bandwidth, while significant, is only 20% of the national goal for new wireless broadband spectrum.

What’s next, then? A framework for spectrum sharing between Wi-Fi and nascent connected vehicle technology would be a good place to start.

To be continued …

Rob Alderfer is a Principal Strategic Analyst for CableLabs, the global research and development consortium of the cable industry, where he guides technology policy and strategy across the industry. He was the Chief Data Officer of the Wireless Telecommunications Bureau at the Federal Communications Commission from 2010 to 2012, leading data-driven wireless policy to encourage investment and innovation in wireless broadband. Previously, he was responsible for overseeing communications policy and programs on behalf of the Administration at the White House Office of Management and Budget.

 

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Security

A Cybersecurity Framework for the Nation’s Critical Infrastructure: How CableLabs is Helping

Mar 26, 2014

Over the past year there has been a significant increase in the number and frequency of cyber-attacks on major retailers, social media sites, and financial institutions.  From identity theft and credit card fraud to denial of service, these cyber criminals are starting to disrupt our lives in small but troubling ways.  What happens when those cyber-attacks move into areas of critical infrastructure like power, water, electricity, and communications?  Attacks on our nation’s critical infrastructure could affect millions of people in a catastrophic way.

To address these concerns, President Obama issued an Executive Order last year aimed at strengthening the cybersecurity of the nation’s critical infrastructure.  The EO tasked the National Institute of Standards and Technology (NIST) with developing a voluntary cybersecurity framework, the Department of Homeland Security (DHS) with helping to promote the adoption of the framework, and regulatory agencies with reviewing and commenting on regulations as they relate to the framework.  Critical infrastructure is owned and operated by both government and industry partners.  In order to address cybersecurity needs NIST, DHS, and the FCC need to partner and work hand-in-hand with industry to accomplish these tasks.

Over the 12 months following the EO, NIST conducted five workshops around the country and invited private industry, government, and academia to work together to develop a cybersecurity framework to help increase the strength and resiliency of the nation’s critical infrastructure.  The framework would be based on industry standards and best practices and addressed cybersecurity capabilities from the top level of an organization (c-suite) to the bottom.

CableLabs, along with several cable member companies, attended and participated in all of the NIST framework workshops.  The cable industry provided input and guidance on the processes and procedures that were included in the framework’s design.  They would meet regularly with the NIST team to discuss concerns as they applied to the cable industry and provide direction in addressing those concerns.  After each release of a framework draft, CableLabs and the member companies provided comments and suggested modifications.  The first version of the framework was released by NIST this past February and has received rave reviews from both industry and government as a great first step in raising the security posture of this country’s cybersecurity.

lock laptop

Once the framework was completed, DHS launched the Critical Infrastructure Cyber Community (C3) Voluntary Program.  The Voluntary Program consists of three major activities:  Supporting the use of the framework, outreach and communications to industry and stakeholders, and feedback into future versions of the framework.  DHS is willing to work with stakeholders in understanding the use of the framework and other risk management efforts, as well as help develop guidance for implementing the framework.  They will be providing tools to help organizations determine their current cybersecurity capability level and use the framework to fill in the gaps.  They will then take the lessons learned from their work with industry and feed it back into the framework to continually evolve it as industries and technologies move forward.

CableLabs and other cable members are actively participating in the Voluntary Program, working with DHS to evolve the framework for the cable industry and provide lessons learned on use of the framework in the cable industry.

In support of the EO directive, the FCC has assigned Working Group 4 (WG4) to focus on using and adopting the framework into the communication sector under the Communication Security, Reliability, and Interoperability Council (CSRIC) IV.  The objective of WG4 is to review the best practices developed during CSRIC efforts and determine if there are any gaps or updates needed in support of the framework.  The group has been divided into four sub-groups to focus on interdependent initiatives.  Those subgroups are:  Segment common practice framework alignment, business security management, barriers to implementation, and shared ecosystem responsibilities.  Each subgroup will focus on their area but will collaborate with each other.

CSRIC IV’s official kickoff meeting for Working Group 4 was March 18.  CableLabs and several cable companies are involved in various working groups under the CSRIC IV.  CableLabs has been identified as a co-chair focusing on small to medium size businesses and impediments to using the framework.  We will be working across the subgroups to provide insight in each area from a small to mid-size company perspective.

CableLabs will be working with our member companies to help them understand and use the framework strategies to help protect their networks as well as their customer data.  We will continue to work with NIST, DHS, and the FCC to provide feedback on the integration efforts and to help drive the evolution of the framework.

With this type of teamwork, along with thoughtful leadership, the United States will be able to protect its critical infrastructure from the types of cyber-attacks that have been dominating recent headlines.

By Susan Joseph, Principal Security Architect, CableLabs –

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Policy

Clearing the Air: FCC Faces Wi-Fi Spectrum Challenges

Rob Alderfer
VP, Technology Policy

Dec 17, 2013

For most of us, Wi-Fi is the way we connect online. It’s the key to our broadband world, and Cable operators are rapidly rolling it out. But the growth of Wi-Fi means that we are using more of the resource, straining wireless capacity. Not only that, but next-gen Wi-Fi, known as 802.11ac or “gigabit Wi-Fi” (since it is designed for blazing fast speeds) is constrained by regulations that dictate how Wi-Fi uses the wireless spectrum.

That’s why all eyes are on Washington. As the FCC greets a new Chairman, it faces the challenge of clearing the air for Wi-Fi, to open up new wireless spectrum that will enable continued growth of the service we all depend on, and to ensure that we all get the benefits of new Wi-Fi technology.

Congress is paying attention, too. A recent hearing on Capitol Hill focused on how to make more spectrum available for Wi-Fi, particularly in the 5 gigahertz frequency band. Tom Nagel of Comcast testified at that hearing, and gave voice to all of us that care about Wi-Fi, emphasizing the importance of the issue and outlining how the FCC can make rapid progress.

What’s so compelling about the 5 gigahertz band, you may wonder? Well, it’s the global home for gigabit Wi-Fi technology being rolled out today, meaning that more 5 gigahertz spectrum for Wi-Fi will mean more speed and capacity for all of us, and quickly. That’s unique in the spectrum world – usually, when more spectrum is made available, it takes years to build the ecosystem so that consumers see the benefit.

To capitalize on this opportunity, the FCC will need to navigate its way through the questions and concerns of a variety of other wireless services that also use 5 gigahertz. Satellite phones, government radar systems, and connected vehicle concepts, to name a few. Luckily, Wi-Fi was designed to play nicely with others – it uses a “listen before talk” approach that makes it perhaps the most polite innovation in communications. That’s a pretty good starting point to build from.

You can help to clear the air for Wi-Fi. Tell us about your experiences. Have you ever experienced wireless congestion? How many connected devices are in your home? What would more and better Wi-Fi mean for you?

As we approach the new year, here’s hoping the FCC will provide a meaningful boost to Wi-Fi – and that the rest of the world isn’t far behind.

Rob Alderfer is a Principal Strategic Analyst for CableLabs, the cable industry research and development consortium, where he guides technology policy and strategy across the industry. He was the Chief Data Officer of the Wireless Telecommunications Bureau at the Federal Communications Commission from 2010 to 2012, leading data-driven wireless policy to encourage investment and innovation in wireless broadband. Previously, he was responsible for overseeing communications policy and programs on behalf of the Administration at the White House Office of Management and Budget. Rob holds a Master of Public Policy from Rutgers University and a Bachelor of Arts from Wilfrid Laurier University.

 

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