Tag Archives: DOCSIS 4.0

Upgrades to DOCSIS 4.0

Cable companies often make it sound like DOCSIS 4.0 is right around the corner. This is the technology upgrade that will increase overall speeds to multiple gigabits while also providing the option for symmetrical speeds.

ATX Networks, a leading manufacturer of electronics for cable companies published the results of a survey in May of cable company executives that shows almost half of cable companies intend to implement DOCSIS 4.0 by the end of 2025. That includes 10% of cable companies that say they have already started the upgrade in 2023.

The upgrade to DOCSIS 4.0 is interesting because vendors are not yet offering gear with a full DOCSIS 4.0 solution. Cable companies seem happy to make a partial upgrade now to get somewhat faster speeds and will likely layer on the rest of the upgrade later.

This says a lot about the mindset of cable companies today. They are being besieged from all directions. The public clearly has formed an opinion that fiber is a superior technology to cable technology. The shift to DOCSIS 4.0 will allow cable companies to claim the same speed capabilities as their fiber competitors. If a cable company can upgrade and serve a small portion of customers with a 2-gigabit broadband subscription, they hope they will have evened the playing field in the marketing battle with fiber providers.

Cable companies are also losing customers at the bottom end of the market to FWA cellular wireless as people settle for slower speeds to get significant price savings. A few cable companies, like Charter, face another big customer loss due to the end of the ACP program.

The survey showed that cable companies are taking different approaches on how to upgrade to DOCSIS 4.0. About one-third of the respondents to the survey said they would be happy to get symmetrical speeds using a network with the overall capacity of 1.2 GHz. This is being referred to as a full duplex (FDX) upgrade) since it will provide symmetrical broadband speeds over an existing 1.2 GHz network. The FDX upgrade will get as much extra speed out of a current cable company network as possible, but it saves cable companies from having to go through the expensive process of updating the outside network and amplifiers.

Other cable companies intend to also upgrade the overall bandwidth capability of the network to 1.8 GHz. This is being referred to as an Extended Spectrum (ESD) upgrade. For those wondering why this is expressed in gigahertz, cable networks operate by using a radio network that is captive within the coaxial cable. The DOCSIS technology assigns different portions of this spectrum to different functions, like delivering broadband or cable TV channels. Cable companies upgrading the overall capacity of the network have significantly increased the overall bandwidth available for broadband.

This is the third annual survey from ATX Networks, and the survey shows that more cable companies are now favoring the FDX upgrade, which will be less costly.

Finally, the survey showed that 15% of the cable companies don’t have plans to upgrade to DOCSIS 4.0. There are some interesting alternate upgrades that can milk faster speeds out of an existing DOCSIS 3.1 network. One intriguing patch is to use a DOCSIS 3.1 headend and connect to DOCSIS 4.0 modems for only the customers who want speeds faster than 1 gigabit. This is being labeled as DOCSIS 3.1 Extended and only involves upgrading modems for customers who are willing to buy the fastest speeds.

There are still cable companies that believe the best option is to convert directly to fiber. For example, Cox is upgrading to fiber in some of its largest markets. But that is by far the most expensive option.

The bottom line is that it’s going to be hard in the future to understand the capability of a local cable market. Cable companies are likely to label all their upgrades as having DOCSIS 4.0, even though the different upgrade paths will create networks with widely different capabilities.

The Future of the Last Mile

The last two blogs in this series looked at the broadband demand for speed and usage. The first blog predicted that demand in 25 years for broadband speeds could be as much as 100 times more than today’s definition of broadband of 100 Mbps download. The second blog predicted that demand for broadband usage in 25-years could conservatively be 12 to 15 times more than today, and could be a lot more.

Today’s blog looks at what that kind of future demand means for last mile technologies. The fastest broadband technology today is fiber, and the most common fiber technology is passive optical network (PON). This technology brings broadband to local clusters of customers. The original PON technology deployed in the early 2000s was BPON, which had the capability to deliver 622 megabits of speed to share in a cluster of 32 homes.

The next PON technology, introduced widely around 2010, was GPON. This technology uses faster lasers that deliver 2.4 gigabits of speed to share in a cluster of 32 homes. The industry has pivoted in the last few years to XGS-PON, which can deliver 10 gigabits of bandwidth to a neighborhood cluster of homes. Vendors are already working on a PON technology that will deliver 40 gigabytes to a cluster of homes. Cable Labs is working on a PON technology they have labeled as CPON that will deliver 100 gigabits of speed to a cluster of homes.

Consider the following table that shows the increase in last-mile fiber bandwidth that comes with PON technologies:

 

 

 

XGS-PON is a great upgrade, but has only 4 times the capacity of GPON. XGS-PON is not going to satisfy broadband needs in 25 years when demand is at least 12 to 15 times greater than today. By then, fiber ISPs will likely have upgraded to 40G PON, which has over 16 times the capacity of GPON. There will be a lot of talk in 25 years of upgrading to something like CPON, with a capacity of over 40 times that of GPON.

Something that cable executives all know but don’t want to say out loud is that cable networks will not be able to keep up with expected future demand over 25 years. The planned upgrade to DOCSIS 4.0 brings cable company technology close to the capability of XGS-PON. DOCSIS 4.0 will allow for multi-gigabit speeds over coax, but there is no planned or likely upgrade for coax to match the capabilities of 40G PON.

Any discussions about boosting the future capacity of cable networks is moot anyway. Most coaxial networks were built between the 1970s and 1990s, and in 25 years the copper will be between 60 and 80 years old. There is no question that the coaxial copper will be past its useful life by then.

A few cable companies have already acknowledged this reality. Altice announced a transition to fiber years ago but doesn’t seem to have the financial strength to complete the upgrades. Cox has quietly started to upgrade its largest markets to fiber. All big cable companies are using fiber for expansion. By 25 years from now, all cable companies will have made the transition to fiber. Executives at the other big cable companies all know this, but in a world that concentrates on quarterly earnings, they are in no rush to tell their shareholders about the eventual costly need for an expensive infrastructure upgrade.

There is no possibility for wireless technology to keep up with the increased demand that will be expected in 25 years. The only way to increase wireless speeds and capacity would be to greatly increase the size of wireless channels – which the FCC is unlikely to do – or use much higher frequencies. We’ve already learned that millimeter-wave and higher frequencies can deliver much faster speed, but don’t play well in an outdoor environment in an end-to-end wireless network. This doesn’t mean that wireless ISPs won’t be delivering broadband for decades to come – but over time, wireless last-mile technologies will fall behind fiber in the same way that DSL slowly fell behind cable modems.

Unless satellite technology finds a way to get a lot faster, it won’t be a technology of choice except for folks in remote areas.

Mobile data is always going to be vital, but there will be major pressure on wireless companies to finally deliver on the promises of 5G to keep up with future demand for speed and bandwidth.

DOCSIS 4.0 vs. Fiber

Comcast and Charter previously announced that they intend to upgrade cable networks to DOCSIS 4.0 to be able to better compete against fiber networks. The goal is to be able to offer faster download speeds and drastically improve upload speeds to level the playing field with fiber in terms of advertised speeds. It’s anybody’s guess if these upgrades will make cable broadband equivalent to fiber in consumers’ eyes.

From a marketing perspective, there are plenty of people who see no difference between symmetrical gigabit broadband offered by a cable company or a fiber overbuilder. However, a lot of the public has already become convinced that fiber is superior. AT&T and a few other big telcos say they quickly get a 30% market share when they bring fiber to a neighborhood, and telcos claim aspirations of reaching a 50% market share within 3-4 years.

At least a few big cable companies believe fiber is better. Cox is in the process of overbuilding fiber in some of its largest markets. Altice has built fiber in about a third of its markets. What’s not talked about much is that cable companies have the same ability to overlash fiber on existing coaxial cables in the same way that telcos can overlash onto copper cables. It costs Cox a lot less to bring fiber to a neighborhood than a fiber overbuilder that can’t overlash onto existing wires.

From a technical perspective, engineers and broadband purists will tell you that fiber delivers a better broadband signal. A few years back, I witnessed a side-by-side comparison of fiber and coaxial broadband delivered by ISPs. Although the subscribed download speeds being delivered were the same, the fiber connection felt cleaner and faster to the eye. There are several technical reasons for the difference.

  • The fiber signal has far less latency. Latency is a delay in getting bits delivered on a broadband signal. Higher latency means that a smaller percentage of bits get delivered on the first attempt. The impact of latency is most noticeable when viewing live sporting events where the signal is sent to be viewed without having received all of the transmitted bits – and this is seen to the eye as pixelation or less clarity of picture.
  • Fiber also has much less jitter. This is the variability of the signal from second to second. A fiber system generally delivers broadband signals on time, while the nuances of a copper network cause minor delay and glitches. As one example, a coaxial copper network acts like a giant radio antenna and as such, picks up stray signals that enter the network and can disrupt the broadband signal. Disruptions inside a fiber network are comparatively minor and usually come from small flaws in the fiber caused during installation or later damage.

The real question that will have to be answered in the marketplace is if cable companies can reverse years of public perception that fiber is better. They have their work cut out for them. Fiber overbuilders today tell me that they rarely lose a customer who returns to the cable company competitor. Even if the cable networks get much better, people are going to remember when they used to struggle on cable holding a zoom call.

Before the cable companies can make the upgrade to DOCSIS 4.0, which is still a few years away, the big cable companies are planning to upgrade upload speeds in some markets using a technology referred to as a mid-split. This will allocate more broadband to the upload path. It will be interesting to see if that is enough of an upgrade to stop people from leaving for fiber. I think cable companies are scared of seeing a mass migration to fiber in some neighborhoods because they understand how hard it will be to win people back. Faster upload speeds may fix the primary issue that people don’t like about cable broadband, but will it be enough to compete with fiber? It’s going to be an interesting marketing battle.

Getting DOCSIS 4.0 to Market

If you read the press releases or listen in on investor calls for the big cable companies over the last year, you might think that the latest cable network technology, DOCSIS 4.0, is right around the corner and will be installed soon. Cable companies have been leaving this impression to fend off competition with fiber. There are millions of new fiber passings being constructed this year where cable companies serve today, and most of the companies building fiber say that they reach at least a 30% market penetration rate within the first year after fiber reaches a neighborhood.

The reality is that it will still be a while until DOCSIS 4.0 networks make it out into neighborhoods. A recent blog from CableLabs spells this out well. This month (July 2023), CableLabs is holding the first big interoperability testing event where different manufacturers will test if their DOCSIS 4.0 equipment is interoperable with other vendors. This kind of interoperability testing is a standard step in the process of moving toward gear that is approved for manufacturing.

Per the CableLabs blog, this testing is a pre-cursor for CableLabs to be able to certify specific brands of modems. The blog describes this as the first interoperability testing event that will look to see if a cable modem can be operational when working with the latest version of DOCSIS 4.0 core equipment. This test also will check if new modems are backward compatible with earlier existing versions of DOCSIS. This is only the first of multiple interoperability tests, and later tests will go deeper into more specific functions such as interfacing with the overall network, backoffice functions, etc.

It’s normal during this kind of testing that bugs are found in the software and hardware, and it’s likely that there will still be tweaks in many of the components of the DOCSIS 4.0 network.

Only after all of the testing is done and CableLabs is happy that all components of the system are operating correctly and will work together properly can the process of certifying equipment from each vendor begin. That involves sending devices to CableLabs for extensive testing and final approval by the CableLabs Certification Board. Only then will any manufacturer put a device into mass production. Any device that doesn’t pass certification will have to be reworked, and the process started again.

It’s hard to think that it won’t be at least another year until devices start to get certified. After that will be the time needed to mass produce, distribute, and install devices. That could easily mean two years before we might see the first DOCSIS 4.0 network being installed.

With that said, this entire process has been exceedingly fast by industry standards. The DOCSIS standards was completed in early 2020. This process is far ahead of where most new technologies would be only three years after standards are completed.

The cable companies are in a huge hurry to be able to declare superfast symmetrical speeds to compete against fiber. I’m sure there has been tremendous pressure on CableLabs to speed up each step of the process. This likely meant faster than normal efforts to create breadboard chips and the components needed for equipment. For example, the normal timeline for getting a new chip designed and built can easily take 18 months. DOCSIS 4.0 chips are likely on an accelerated timeline.

Who can say how long it will take cable companies to upgrade networks to DOCSIS 4.0? They will certainly start in the markets where they think the technology makes the most market sense. It could easily take several years to make this upgrade nationwide, assuming that manufacturers will be able to keep up with the demand.

Fearing the Competition

Over the last six months, practically every big carrier in the industry has made a formal announcement that they are not worried about specific competitors. The latest one I read was in LightReading where Nick Jeffery of Frontier said he’s not worried about competition from the cable companies upgrading to DOCSIS 4.0 or from cellular carriers offering FWA home broadband. Frontier is building a lot of fiber, and Jeffery was commenting that he thinks fiber is a superior technology compared to the alternatives. To be honest, this might be the only claim I read where the ISP was being truthful. Frontier has been at the bottom of the heap in the industry for many years and led in the percentage lost broadband and cable TV customers quarter after quarter. It’s got to be refreshing for the company to be deploying a technology that gives it a fighting chance to succeed.

I’m not citing all of the other CEOs that said the same thing – but these announcements were pretty much across the board – basically, no carrier is afraid of other competitors.

I’ve seen all of the big cable companies quoted as saying they aren’t afraid of FWA cellular broadband. And yet, in the second quarter of this year, T-Mobile and Verizon added over 800,000 new customers, while the large cable companies collectively lost 150,000 customers during the quarter. The cable companies rightfully say they have superior technology when competing against 100 Mbps download speeds, but the FWA cellular carriers have much lower rates and are attracting customers who think that cable broadband costs too much.

The big telcos that are building fiber have all made the same claim about not fearing FWA wireless. The big telcos collectively lost less than 100,000 customers in the second quarter of this year, the best they’ve done in ages. The small loss disguises the fact that the telcos continue to lose DSL customers but are largely replacing them with fiber customers – except Lumen, which had a net customer loss for the quarter of 93,000.

I’ve seen most of the big fiber overbuilders scorning cable company broadband and saying they aren’t worried about DOCSIS 4.0 – like Frontier said. That’s a fairly easy thing not to fear for now since we’re a number of years away from any conversions to DOCSIS 4.0. But Comcast and others are talking about soon introducing some of the higher split technologies on DOCSIS 3.1 to boost upload speeds sooner. Will fiber overbuilders fear the cable companies more after some upgrades?

The WISPs that will be installing new versions of fixed wireless, including some technologies that claim to be able to deliver speeds up to a gigabit, say they are not afraid of competing against rural fiber networks built with grant funding. That’s an interesting claim since the general public seems to have grasped that fiber is better. It will be interesting to see what happens in places where rural fiber competes against fast rural broadband.

The big three cellular carriers all claim they are not afraid of Dish Network becoming the fourth major cellular carrier. It’s an odd claim to make since Dish says the only way for it to gain market share is to be extremely aggressive with prices. The cellular industry is already highly competitive, and it can’t be good for any of the bigger carriers to have to lower rates.

I get a chuckle every time I read one of these statements because when a carrier goes out of its way to mention a competitor, it is worried. The reality is that every carrier in a competitive situation has to be concerned about competitors. In the end, this is a battle that is going to be fought at the local level, market by market. I can picture that the various technologies will get a different reception depending on local factors. But for now, apparently, nobody fears the competition.

Faster Speeds for Comcast

Comcast held a press release on September 8 that announced the introduction of a 2-gigabit download broadband product. The product is already available in Colorado Springs, CO, Augusta, GA, Panama City Beach, FL, and in the Comcast headquarters market of Philadelphia. I can’t find any mention yet of the price.

Along with the announcement of faster download speeds, the company is claiming new upload speeds of as much as 200 Mbps – at least for the 2 Gbps plan. The press release made it sound like all upload speeds would be increased by five to ten times the existing speeds, and today’s blog looks at what it would take for a cable company to increase upload speeds across the board.

Interestingly, the same press announcement said that Comcast would be introducing DOCSIS 4.0 in 2023, at least for some business customers. That’s an announcement that has me scratching my head. Comcast just announced a successful test for DOCSIS 4.0 in January of this year. To be able to go from a lab prototype to production units in less than two years would be extraordinary. The normal time to market for a major new technology is five or six years. I’m skeptical about the announcement and wonder if this is aimed at Wall Street more than any actual technology plan. The company has been asked non-stop about DOCSIS 4.0 for several years, and maybe this announcement is taking advantage of that hype. Comcast could hold a field trial of the new technology next year and still meet this promise.

But cable companies have another option to get faster upload speeds. A cable network is essentially a captive radio network inside of the coaxial cable. Cable networks don’t all have the same total bandwidth, and most of the big cable company networks have total bandwidth of either 1 GHz or 1.2 GHz. The total bandwidth has to be shared between video channels and broadband.

Most existing cable companies have allocated bandwidth between download and upload using something called the sub-split. This assigns a relatively small amount of frequency between 5 MHz and 42 MHz for upload. On top of being a small swath of throughput, this is also the part of the spectrum that suffers from external interference. This combination results in both relatively slow upload speeds and also variable speeds due to interference – something most cable customers are aware of.

There are two additional configurations for allocating upload speeds. A mid-split configuration uses the spectrum between 5 MHz to 85 MHz for upstream. In a high-split, the upload is enhanced by using the spectrum up to 204 MHz. DOCSIS 4.0 will provides multiple options for upload bandwidth with possible spits at 300 MHz, 396 MHz, 492 MHz, and 684 MHz.

If Comcast is going to improve bandwidth in the near future, it will have to implement one of the larger DOCSIS 3.1 splits. There is a cost for moving to a different split. There must first be enough room available for video channels and download bandwidth. It can be expensive if the entire bandwidth of the network must be increased. That can mean replacing amplifiers and other outside electronics, and even some coax. In most cases, the existing customer modems would need to be replaced unless already configured to accept the different split.

At the recent SCTE Cable-Tec Expo, CommScope, Vecima, and CableLabs said there are plans for a different upgrade path for the DOCSIS 3.1 higher splits. They are claiming new ‘turbocharged’ modems that will add more effective upload bandwidth capability. I’ve not heard of any field trials of the new modems, and perhaps this is what Comcast has in mind by the end of 2023.

Cable companies are sensitive about the marketing advantage that faster upload speeds give to fiber and even to slower technologies like FWA cellular wireless. It’s hard to know if the Comcast announcement foreshadows big improvements next year or was just a way to signal to Wall Street that cable companies are working towards improved bandwidth. It’s inevitable that faster upload bandwidth is coming – the big questions are when and how much faster.

Update on DOCSIS 4.0

LightReading recently reported on a showcase at CableLabs where Charter and Comcast demonstrated the companies’ progress in testing the concepts behind DOCSIS 4.0. This is the big cable upgrade that will allow the cable companies to deploy fast upload speeds – the one area where they have a major disadvantage compared to fiber.

Both companies demonstrated hardware and software that could deliver a lot of speed. But the demos also showed that the cable industry is probably still four to five years away from having a commercially viable product that cable companies can use to upgrade networks. That’s a long time to wait to get better upload speeds.

Charter’s demonstration was able to use frequencies within the coaxial cables up to 1.8 GHz. That’s a big leap up from today’s maximum frequency utilization of 1.2 GHz. As a reminder, a cable network operates as a giant radio system that is captive inside of the coaxial copper wires. Increasing the range of spectrums used means opening up a big range of additional bandwidth capacity inside of the transmission. These new breakthroughs are akin to the creation of G.Fast which harnesses higher frequencies inside the telephone copper wires. While engineers can theoretically guess how the higher frequencies will behave, the reason for these early tests is to find all of the unexpected quirks of how the various frequencies interact inside of the coaxial network in real-life conditions. A coaxial cable is not a sealed environment and allows interference from the outside world that can interfere unexpectedly with parts of the transmission path.

Charter used equipment supplied by Vicma for the node, Teleste for amplifiers, and ATX Networks for taps. The node is the electronics that sit in a neighborhood and converts the signal from fiber onto the coaxial network. Amplifiers are needed because the signals in a coaxial system don’t travel very far without having to be amplified and refreshed. Taps are the devices that peel signals from the coaxial distribution network to feed into homes. A cable company will have to replace all of these components, plus install new modems, to upgrade to a higher frequency network – which means the DOCSIS 4.0 upgrade will be expensive.

One of the impressive changes from the Charter demo was that the company said it could overlay the new DOCSIS system over top of an existing cable network without respacing. That’s a big deal because respacing would mean moving existing channels to make room for the new bandwidth allocation.

Charter was able to achieve a download speed of 8.9 Gbps download and 6.2 Gbps upload. They feel confident they will be able to get this over 10 Gbps. Comcast achieved speeds on its test of 8.2 Gbps download and 5.1 Gbps upload. In addition to researching DOCSIS 4.0, Comcast is also looking for ways to use the new technology to beef up existing DOCSIS 3.1 networks to provide faster upload speeds earlier.

Both companies face a market dilemma. They are both under pressure to provide faster upload speeds today. If they don’t find ways to do that soon, they will lose customers to fiber overbuilders and even the FWA wireless ISPs. It’s going to be devastating news for cable stock prices in the first quarter after Charter or Comcast loses broadband customers – but the current market trajectory shows that’s likely to happen.

Both companies are still working on lab demos and are using a breadboard chip designed specifically for this test. The normal lab development process means fiddling with the chip and trying new versions until the scientists are satisfied. That process always takes a lot longer than executives want but is necessary to roll out a product that works right. But I have to wonder if cable executives are in a big hurry to make an expensive upgrade to DOCSIS 4.0 so soon after upgrading to DOCSIS 3.1.

AT&T Feels Sorry for Cable Companies

In a recent interview given to Diana Goovaerts of FierceTelecom, Chris Sambar, the AT&T EVP of Technology Operations said that the company is not worried about competition from cable companies. He said that AT&T’s fiber technology, which is capable of symmetrical 10-gigabit speeds is far beyond the capability of the cable companies.

He rightfully identified that cable companies must spend a lot on DOCSIS 4.0 to come close to catching up with fiber. What he didn’t mention is that the new cable technology is probably five years away from being market-ready. His zinger in the interview was when he said, “I almost feel bad for them (the cable companies)”.

This is interesting because we haven’t seen any real trash-talking between telcos and cable companies in decades. There was a lot of noise when DSL and cable modems both had 1 Mbps download capabilities, and then again when Verizon first launched FiOS. This quote is going to be talked about in every cable company board room in the coming months because it encapsulates an industry of fiber providers that are not afraid of tackling the cable companies head-on.

The cable companies have had an unprecedented run of clobbering DSL in the market and becoming near-monopolies in most urban markets. My firm hasn’t done a survey in several years where the cable company hasn’t captured at least two-thirds of broadband customers in an urban market.

But as AT&T and other telcos undertake an aggressive fiber overbuilding program, the industry is about to change. AT&T alone plans to pass an additional 15 million homes and businesses by the end of 2025. We also see aggressive buildouts planned by Verizon, Frontier, Windstream, Consolidated, and many others.

AT&T’s CEO John Stankey was quoted last year saying that the company believes that it will gain at least a 50% market share within three years after building fiber in a neighborhood. Some of those customers will be AT&T DSL customers converted to fiber, but a lot of the customers are going to be coming from the cable companies.

If the broadband world only consisted of the cable companies and the big telcos, we could pass off this latest episode as posturing by two industries that intend to continue to share duopoly market power. Telcos will win back customers with fiber, but if the two big incumbents were the only competitors in markets, then after a few years, we’d see a new equilibrium with telcos bigger than today. That’s what we’ve seen in the Northeast in the years since Verizon built its FiOS fiber – Verizon and the cable companies reached an equilibrium where each enjoys high prices and where both are profitable.

But the world is changing around the two big sets of incumbents. There are other competitors edging into urban broadband markets. For example, in the fourth quarter of 2021, T-Mobile added 224,000 customers to its fixed cellular home broadband. While this is being offered in rural areas, T-Mobile says most of its gains are coming from suburban and urban markets where the product offering of decent 100 Mbps speeds and low prices is peeling customers from both the cable companies and the telcos. While 224,000 new customers may not sound like a lot, the whole rest of the broadband industry only added 632,000 net customers in the third quarter of last year. T-Mobile has quickly grown to 646,000 total home broadband customers and will soon break into the top ten list of ISPs.

If T-Mobile was the only competitor, there still wouldn’t be much concern from the big companies. But both AT&T and Verizon are getting ready to unleash a nationwide rollout of a fixed wireless product similar to T-Mobile’s. We’re also seeing the rudimentary beginnings of other wireless providers like Starry, which said it plans to grow to 1.4 million customers by 2026. As mentioned earlier, there are millions of lines of fiber being built each year by Frontier, Windstream, Consolidated, TDS, and many other smaller players – all of these ISPs have the cable companies in their crosshairs.

AT&T has thrown down the gauntlet for the cable companies. The cable companies can watch customers erode while waiting for DOCSIS 4.0. Or the cable industry could follow the lead of smaller cable companies like Altice and start converting to fiber now. But unlike AT&T, which will get new revenues to help pay for fiber, the cable companies already have a large majority of customers in most markets. Building fiber will be harder to justify for the cable companies if they are losing customers.

Comcast and Charter still see the lion’s share of the growth of cable customers each quarter. We’ll really know the cable companies are in trouble when we see that metric slip. If everything AT&T says comes to pass, we ought to see cable companies losing customers a few years from now.

Network Function Virtualization

Comcast recently did a trial of DOCSIS 4.0 at a home in Jacksonville, Florida, and was able to combine various new techniques and technologies to achieve a symmetrical 1.25 Gbps connection. Comcast says this was achieved using DOCSIS 4.0 technology coupled with network function virtualization (NFV), and distributed access architecture (DAA). Today I’m going to talk about the NFV concept.

The simplest way to explain network function virtualization is that it brings the lessons learned in creating efficient data centers to the edge of the network. Consider a typical data center application that is to provide computing to a large business customer. Before the conversion to the cloud, the large business network likely contained a host of different devices such as firewalls, routers, load balancers, VPN servers, and WAN accelerators. In a fully realized cloud application, all of these devices would be replaced with software that would mimic the functions of each device, all operated remotely in a data center consisting of banks of super-fast computer chips.

There are big benefits from a conversion to the cloud. Each of the various devices used in the business IT environment  is expensive and proprietary. The host of expensive devices, likely from different vendors are replaced with lower-cost generic servers that run on fast chips. A host of expensive electronics sitting at each large business is replaced by much cheaper servers sitting in a data center in the cloud.

There is also a big efficiency gain from the conversion because inevitably the existing devices in the historic network operated with different software systems that were never 100% compatible. Everything was cobbled together and made to work, but the average IT department at a large corporation never fully understood everything going on inside the network. There were always unexplained glitches when software systems of different devices interacted in the work network.

In this trial, Comcast used this same concept in the cable TV broadband network. Network function virtualization was used to replace the various electronic devices in the Comcast traditional network including the CMTS (cable modem termination system), various network routers, transport electronics for sending a broadband signal to neighborhood nodes, and likely the whole way down to the settop box. All of these electronic components were virtualized and performed in the data center or nearer to the edge in devices using the same generic chips that are used in the data center.

There are some major repercussions for the industry if the future is network function virtualization. First, all of the historic telecom vendors in the industry disappear. Comcast would operate a big data center composed of generic servers, as is done today in other data centers all over the country. Gone would be different brands of servers, transport electronics, and CMTS servers – all replaced by sophisticated software that will mimic the performance of each function performed by the former network gear. The current electronics vendors are replaced by one software vendor and cheap generic servers that can be custom built by Comcast without the need for an external vendor.

This also means a drastically reduced need for electronics technicians at Comcast, replaced by a handful of folks operating the data center. We’ve seen this same transition roll through the IT world as IT staffs have been downsized due to the conversion to the cloud. There is no longer a need for technicians that understand proprietary hardware such as Cisco servers, because those devices no longer exist in the virtualized network.

NFV should mean that a cable company becomes more nimble in that it can introduce a new feature for a settop box or a new efficiency into data traffic routing instantly by upgrading the software system that now operates the cable network.

But there are also two downsides for a cable company. First, conversion to a cloud-based network means an expensive rip and replacement of every electronics component in the network. There is no slow migration into DOCSIS 4.0 if it means a drastic redo of the underlying way the network functions.

There is also the new danger that comes from reliance on one set of software to do everything in the network. Inevitably there are going to be software problems that arise – and a software glitch in an NFV network could mean a crash of the entire Comcast network everywhere. That may sound extreme, and companies operating in the cloud will work hard to minimize such risks – but we’ve already seen a foreshadowing of what this might look like in recent years. The big fiber providers have centralized network functions across their national fiber networks, and we’ve seen network outages in recent years that have knocked out broadband networks in half of the US. When a cloud-based network crashes, it’s likely to crash dramatically.

Will Cable Companies Ignore Pleas for Faster Uploads?

One of the biggest impacts of the pandemic on broadband networks has been that homes suddenly care about upload speeds. Homes that largely lived off of downloading video transitioned to having adults and students at home and simultaneously trying to connect to remote work and school servers. People who were happy with their broadband speeds pre-pandemic suddenly found their broadband connection to be inadequate. Industry statistics show that huge numbers of people have upgraded to faster broadband products hoping to improve the home broadband performance without realizing that their performance bottleneck is due to inadequate upload speeds.

The cable industry has largely ignored upload bandwidth in the past. DOCSIS technology that operates the cable broadband networks allows as much as one-eight of total bandwidth to be dedicated to uploading. However, many cable broadband connections are configured with something less than that, because very few homeowners, other than perhaps photographers or others professionals who routinely send big files have ever cared about upload speeds. To make matters worse, the cable industry generally has squeezed the upload data stream into the portion of a cable network spectrum that has the most noise and interference. That never mattered to most people when sending files, but it matters when trying to maintain a steady connection to a work or school WAN.

But suddenly upload speeds matter to a lot of households. Some of the current pressure on upload speeds will be mitigated as K12 students eventually return to the classroom, but there seems to be widespread consensus that we’re going to see more adults permanently working from home.

It’s going to be interesting to see how the big cable companies react to the upload crisis. I’ve not seen many of them talking about the issue publicly and I suspect they are hoping this will go away when the pandemic ends. The cable companies have to know that they will be competing against technologies that offer faster upload data speeds. AT&T built fiber in the last few years to pass over 12 million homes. Telcos like CenturyLink and Windstream are quietly building fiber in some communities. Verizon says it’s going to pass 30 million homes with its fiber-to-the-curb technology using millimeter wave spectrum. And private ISPs are edging fiber into cable markets all over the country.

The cable companies have possible solutions on the horizon. Cable Labs recently announced the release of the DOCSIS 4.0 standard that will allow cable companies to offer symmetrical bandwidth. The gear for this technology ought to hit the market starting next year, but industry tech writers who interview cable company management seem to agree that the big cable companies have no appetite for paying for a new round of upgrades.

The cable companies all upgraded to DOSCSIS 3.1 in the last few years that added the capability for a gigabit download product. The web is full of pronouncements from the CTOs of the big cable companies saying that they hope to get a decade out of this last upgrade. Are any of these companies going to be willing to make a major new investment in new technology so soon after the last upgrade? In many markets the cable companies have become de facto monopolies, and that inevitably leads to milking technology upgrades for as long as possible.

There are a few other technology upgrades on the horizon that could provide relief for upload speeds. There has been a move by several vendors to explore expanding the bandwidth used inside a coaxial cable. A coaxial cable network acts like a captive radio network that uses a big range of different frequencies. Cable systems historically used as much as 1 GHz of total spectrum. In recent years with the advent of DOCSIS 4.0 that’s been expanded to 1.2 GHz of total spectrum. The technology now exists to upgrade cable networks to 1.8 GHz. That would provide a huge additional pile of spectrum that could be dedicated to bandwidth. But such an upgrade would require changing out a lot of network components such as amplifiers, power taps, and modems. Such an upgrade might be nearly as expensive as a shift to DOCSIS 4.0.

The bottom line is that any significant changes to create more upload bandwidth inside cable networks will cost a lot of money. I bet that the big cable companies will stick with the current technology migration plan that would keep DOCSIS 3.1 for the rest of this decade. Likely the only thing that might prompt cable companies to upgrade sooner would be competitors mass deploying technologies that are marketed for having faster upload speeds. The most likely future is that the big cable companies will introduce DOCSIS 4.0 selectively in the few markets where they are feeling competitive pressure, but that most of households are not going to see the upload speeds that people now want.