DOCSIS 3.1 Makes Cable Act Like Fiber

By: John Shepler

Cable broadband, once thought to be a low-end networking option, has been quietly getting a major technological overhaul that makes it competitive with fiber optic bandwidth for many business applications. Companies that once wouldn’t consider cable for more than a backup connection now find the combination of high performance and low cost too compelling to ignore. Let’s take a look at what’s happened behind the scenes and what options cable offers now and in the near future.



Magic #1: The HFC Cable Plant
When cable started out as cable television, it was little more than a set of really tall antennas feeding tuners and distribution amps at the “head end” to create an equivalent to what you would get off the air…if you could get such good reception. The all-analog collection of signals got boosted and distributed all over town, but what came out the connector on your TV was very much a more potent version of OTA (Over The Air) Television.

Time passes and the handful of OTA channels were augmented by dozens and dozens of non-broadcast channels delivered via satellite to that same head end. These “cable channels” quickly ate up all the capacity of the big coaxial cables that fed the little coax cables that fed the TVs. Cable companies launched rebuilding programs to increase capacity… but not by doing more of the same. Instead, they strung new fiber optic bundles and then connected their existing delivery cables to the new fiber optic trunk lines. This combination is called HFC or Hybrid Fiber-Coax.

The HFC system, combined with all-digital transmission creates a huge increase in capacity to accommodate a hundred or more TV channels with extras that can be used to deliver Internet broadband over the same cable. Note that the cable that connects to your TV or modem looks the same as the old analog cable. It is. But, it only needs to run a short distance before it hooks up with the enormous capacity fiber optic network. You get the best of both worlds… high capacity fiber to the curb plus inexpensive passive coaxial cable for termination of the service in the home or business.

Magic #2: DOCSIS Broadband
DOCSIS is a cable broadband standard that stands for Data Over Cable Service Interface Specification. It was created specifically for cable companies to be able to also deliver Internet. To do that, DOCSIS signals fit into low frequency spectrum not used for TV signals and spare standard television channels on the cable.

The first version, DOCSIS 1.0 was released about the same time as the Internet was taking off, 1997, followed by version 1.1 in 1999. A faster version 2.0 came out in 2001. That’s the one most of us cut our broadband teeth on, after finally running out of patience with dial-up telephone Internet. A few years ago you probably upgraded to a DOCSIS 3.0 modem, which brings the system up to today’s standards.

DOCSIS 3.0 makes cable a serious contender for business broadband service. It supports the latest Internet Protocol version 6 (IPV6) and has a downstream (download) capacity of 1 Gbps with an upstream (upload) capacity of 100 Mbps. In practice, may users run something like 25 to 75 Mbps down and 5 to 7 Mbps up.

Magic #3 DOCSIS 3.1 Thinks It’s Fiber
The newest technical upgrade to HFC systems is called DOCSIS 3.1. It sounds like an incremental change, but the performance jump is enormous. DOCSIS 3.1 offers downstream speeds of 10 Gbps max with upstream of 1 to 2 Gbps max. Cable bandwidth is called asymmetrical because the download speeds are typically 10x the upload speeds. A further enhancement, not yet deployed, is Full Duplex DOCSIS 3.1 that will offer 10 Gbps upload and 10 Gbps download. That’s pretty much the high end of what you’ll get with fiber or by leasing a fiber optic wavelength… at a fraction of the cost.

The Appeal of High Speed Cable Broadband
Cable broadband is the most compelling Internet access for any business that can get it. You do need to be in a location with cable already running down the street, but you stand a much better chance of having cable available than fiber. It’s mostly out in rural areas that neither fiber or cable are available and high speed satellite becomes the service of choice.

The big appeal of cable is how much bandwidth you get for the money. You’ll easily pay 5x to 10x as much for SONET or Ethernet fiber optic services. In some cases, that extra expense is worth it. Cable bandwidth is shared among the pool of users, while higher priced telecom services have dedicated bandwidth for your use only. SONET and Ethernet over Fiber services are symmetrical and come with service level agreements that guarantee a certain level of performance and availability at all times.

If your business is running a server farm in-house or distributing large software packages or video streams, you’ll need a high speed dedicated service. But, if your business uses cloud services, collocated hosting, or has simple needs for web browsing and email, cable broadband may have all the capacity you can use and at bargain rates. You should at least give it consideration before you sign an expensive lease. Our expert consultants can help you make the best decision based on the particular needs of your business. Compare DOCSIS cable with other copper, fiber and satellite bandwidth options available for your business location.

Upgrading to Fiber FAQ

By: John Shepler

The bandwidth solution you’ve had for years is running out of capacity. It’s worked well for you, but now you have no real choice but to upgrade to something faster, more reliable, lower latency, more consistent or all of the above. How about fiber? You’ve always had twisted pair copper or cable. Does fiber make more sense for the future and… can you afford it? Let’s look at some key questions and answers for making this decision.

What Can Fiber Do That Copper Can’t?
The real beauty of fiber isn’t necessarily what it will do for you today. It’s the virtually unlimited upgradability down the road that is unique to fiber. Every copper technology runs out of capacity at some level. Technology advancements have expanded copper’s capability and extended its life. However, technology advancements have also expanded fiber capacity beyond what most of us can fathom needing.

I Have a T1 Line Now and Love It. Can’t I just Add Another T1?
You bet you can. The process is called bonding. It makes 2 T1 lines act like a single line with twice the bandwidth. You can bond T1 lines up to 10 or 12 Mbps, which is about the entry level for fiber. One limitation is that you have to get all your lines from the same provider to bond them. A more serious limitation is cost. You may find that 10 Mbps fiber is a lot less expensive than 10 Mbps bonded T1.

What About Ethernet over Copper?
EoC is a competing technology to T1 and uses the same twisted pair copper. You can get higher bandwidths at lower cost than T1, but the technology is distance sensitivity. For 10 to 50 Mbps, you need to be geographically close to the office supplying your service. For higher bandwidths, say 100 Mbps and up, it’s rare to find EoC available. At 1Gbps, it’s pretty much fiber all the way.

Don’t Cable Companies Offer Fiber Bandwidth over Cable?
Yes and no. Yes, you can get hundreds of Mbps, perhaps even Gbps, bandwidth over the same coaxial cable that brings in hundreds of TV channels. This is relatively inexpensive service, but it is a “shared” bandwidth that varies with the number of users online. It’s strictly Internet access, not private line, and has no performance guarantees. For demanding business operations, the Cable companies offer competitive fiber optic service using their core transmission networks. This grade of service is similar to what you get from telecom companies.

OK, But Isn’t Fiber Hard to Get?
Not any more. The first fiber technology, called SONET, is a telephone company product and has been both expensive and limited in availability. A newer technology called Ethernet over Fiber is offered by a wide array of competitive carriers, including many traditional suppliers. Nobody is building out copper plant anymore. It’s yesterday’s news. All of the new network construction is fiber and there is a race among carriers to capture the business market

Where is Fiber Available?
Ethernet over Fiber and SONET are both readily available in major metropolitan areas. Fiber is also often available in suburban areas and smaller cities. There is a big push right now to replace T1 lines with fiber to increase the bandwidth of cell towers from 3G to 4G and, eventually, 5G. That is extending metro fiber networks out into the countryside where they haven’t been before. Eventually, fiber will be everywhere.

What About Now? Where Can I Get Fiber?
Your best bet is to be located in an already “lit” building. That means the building has fiber optic service installed and operating. Once the terminal equipment is in place, adding another customer in the same location is trivially easy for the carriers. If you can’t be in a lit building, you’ll need to be near enough that construction costs are minimal. It’s those long distance runs that need new fiber installed that get expensive.

Note: A popular option for companies that find fiber construction costs too much to consider is to locate their high bandwidth equipment, such as servers, in a colocation data center where multiple fiber options are readily available.

So, Where Are These Lit Buildings?
Lit buildings and nearby fiber optic services can be easily located using the Telarus GeoQuote search engine. This is a tool specifically developed to quickly locate existing fiber services. You can find out in seconds what’s available in your area with no commitment.

Great, I’ve Found Fiber Service. Will It Cost a Fortune?
You may be shocked to find how affordable fiber optic service is today. This isn’t consumer grade FTTH (Fiber to the Home). It’s a business grade service that is installed at commercial locations. Bandwidth generally starts at 10 Mbps, which is the same speed as traditional Ethernet. If you’ve had your T1 line for many years and haven’t negotiated a lower priced contract, you may find that you can get 10 Mbps fiber for about the same price. Yes, you’ll pay more for Ethernet over Fiber than today’s T1 lines or low cost business cable broadband, but you can also expect higher performance.

How Much Bandwidth Makes Sense?
Many smaller businesses can get by with 10 Mbps Ethernet over Fiber. High tech or medium size operations will want 100 Mbps Fast Ethernet. Nowadays, Gigabit Ethernet is well within reason for companies that need highly responsive cloud applications or make extensive use of video. Municipalities and school districts often find that Gigabit Ethernet or GigE is exactly what they need at a reasonable price point.

How Easy Are Upgrades
Legacy T-Carrier (T1, T3) and SONET (OCx) services can take a long time to provision because each bandwidth level has a unique interface. Ethernet over Fiber is designed to be easily scalable. You install a port with the maximum speed you expect to need (usually 100 Mbps or 1 Gbps). Then you pick the bandwidth you want to start out with. Often a quick call to your provider is all it takes to increase or decrease bandwidth within hours or days. Some services even let you make the changes yourself through a Web browser.

What’s the Maximum Bandwidth Available?
It’s not likely you’ll ever run out. Gigabit Ethernet service is common. So is 10 Gbps now. In some locations you can get 100 Gbps business bandwidth. That level will become more widely available in the future, as more bandwidth intensive requirements demand it. If you are a really high bandwidth user or have special protocol or security requirements, you might consider wavelength service. Each fiber can carry dozens of wavelengths. Each wavelength transports up to 10 Gbps.

Are you interested in finding out what fiber optic service options are available for your business location and how much they cost? Get fast quotes with no obligation and complementary expert consulting to help choose the best option for your needs.

DS3 and Fractional DS3 Broadband

In the quest to upgrade bandwidth, companies have generally turned to DS3 bandwidth service. Here is what DS3 is all about and the different technologies used to provide DS3 and similar mid-level bandwidth services.

DS3 stands for Digital Signal 3, a standardized switched circuit TDM telecom service. As a refresher, DS0 is the basic building block at 64 Kbps. That’s one channel of digitized telephone call. DS1 is a bundle of 24 DS0 channels at 1.5 Mbps. You are probably more familiar with its implementation as a line service called T1. DS3 is the next step up at 45 Mbps. It’s a bundle of 672 DS0 channels as a large telephone trunk or 28 T1 lines multiplexed together for transport. When you order a T3 line, you are getting the line service implementation of DS3.

Even though DS1 and DS3 were originally conceived as telephone company technologies, they are more often used to transport data packets today. That includes private point to point lines and dedicated Internet connections. In these applications, the entire payload is used to transport data packets.

A full DS3 circuit will give you 45 Mbps bandwidth in both the upload and download directions. This is the most common service ordered and is readily available nationwide. You’ll need an interface card for your router to connect to a DS3 termination. There are two interconnect cables, one for transmit (upload) and one for receive (download). They are 75 ohm coax, similar to what you’ll find for Cable TV connections, although the specified cable type is Bellcore 734 or 735 for this application. The connectors are type BNC. You’ll find these on the router interface card. There may be more than one pair if the router can handle multiple DS3 connections.

At this point, you might be imagining coaxial cables stretched from your building back to the telephone central office, like the twisted pairs used for T1 and multi-line telephone service. In practice, the coaxial connection is only used for short distances. The DS3 bandwidth itself is most often delivered over a SONET fiber optic cable, where it is demultiplexed and dropped off at your premises.

DS3 bandwidth may be higher than you require. There’s a big gap between T1 line bandwidth at 1.5 Mbps and DS3 at 45 Mbps. Companies often begin scaling up their bandwidth by bonding multiple T1 lines to double or triple the individual line bandwidth. This works up to about 10 or 12 Mbps in most cases. Let’s say you only need 20 or 30 Mbps right now. What do you do?

One option is to order fractional DS3 service. A full DS3 interface is installed, but the line bandwidth is limited to the fractional amount you order. That could be 15, 20 or 30 Mbps. You can possibly save money this way, but not necessarily. The reason is that full DS3 is more of a standard service that is readily available. The fractional services are a special order that may or may not be available in a particular location, depending on the service provider. In the end, it might make the most economic sense to get a full DS3 connection.

There are other technical options in this bandwidth range that compete with fractional and even full DS3. The most popular is Ethernet over Copper. This is a highly scalable service that competes with T1 at the 1.5, 2, and 3 Mbps levels. You can also get 10, 15, 20, 25, 30, 50, and sometimes even 100 Mbps Ethernet over Copper. This lets you match your budget more closely to the bandwidth you require. Ethernet over Copper (EoC) is often less expensive than either T1 or DS3 for similar bandwidths, although not as readily available as yet.

Downtown in major business districts you may also find fixed wireless bandwidth services. These often deliver DS3 bandwidths, but perhaps in an Ethernet protocol. Most of the time that’s what you want anyway, since you’ll be connecting to a LAN running Ethernet.

A final option isn’t DS3, but might give you a similar benefit for a lot less money. That’s business class Cable broadband. It is shared, not dedicated, and the bandwidth varies with the amount of user activity. Still, you can get up to 50 or 100 Mbps download with 5 or 10 Mbps upload service for about the price of a T1 line. You’ll need to have the cable passing by your business location for this service to be available. Otherwise the construction costs are prohibitive.

Are you in need of higher bandwidth to support your growing business, additional computerization or a move to cloud services? If so, get pricing and availability for DS3 and fractional DS3 services, plus related bandwidth services that may also meet your needs.

What Is a DS3 Circuit Or T3 Line?

Companies that have outgrown their T1 lines often upgrade to DS3 bandwidth. Let’s take a look at what DS3 has to offer, how it relates to T3 lines, and recent competition from Ethernet over Copper services.

DS3 stands for Digital Signal level 3. The specification for it is found in the T-carrier standards developed by Bell Labs for the telephone industry. The way it works is that DS0 is the smallest unit with a bandwidth of 64 Kbps. That’s just the right size to transport one digitized telephone call using PCM (Pulse Code Modulation), the original digital phone standard. You combine 24 DS0s to create a DS1 that runs on a T1 line. DS3 is the equivalent of 28 DS1s or 672 DS0s.

You’ll often hear DS3 referred to as T3, like DS1 is called T1. The fine line of difference between DS3 and T3 is that DS3 refers to the actual structure of the data stream and T3 refers to the physical transmission layer. Most of the time, they are treated as equivalent. The reason that the digital signal has its own definition is that you can multiplex DS3 as well as DS1 to make much larger bandwidth services. At the far end, you can then demultiplex the signals to recover the original DS3 or DS1.

Combine the 672 voice channels plus the bits needed for synchronization and line maintenance and you have a bandwidth of 44.736 Mbps. That’s commonly referred to as 45 Mbps. You can order DS3 as a telephone trunk line if you have a high capacity phone systems like a PBX serving a major corporation. You can also order DS3 as a data line with one big chunk of bandwidth, namely 45 Mbps.

If you order a T3 line or DS3 service, it will be delivered to you on a pair of 75 ohm coaxial cables using BNC connectors. Look at a DS3 router card and you’ll see the connectors, one for receive and one for transmit. Some cards support more than one DS3 connection so you’ll see multiple sets of connectors.

The coaxial cable used to connect your DS3 router can be no more than 450 feet in length (only 225 feet if using small diameter coax). That’s fine for connecting to the telco demarc in your building, but how does the DS3 get to the central office?

The actual provisioning of DS3 services can be via fixed wireless transmission or SONET fiber optic service. DS3 can be easily encapsulated into a SONET STS-1, as they are both telco standards designed to be compatible. An OC-3 service can carry 3 STS-1s for 3 DS3s.

What if you are not in range for fixed wireless and there’s no fiber in the area? Are you stuck with the 1.5 Mbps T1 bandwidth? No, not really. T1 lines can be bonded to create larger bandwidths. This works well up to 10 or 12 Mbps. Bridging the gap between bonded T1 and DS3 is Ethernet over Copper. This technology also uses multiple copper pair instead of fiber strands, but can deliver much higher bandwidth than T1 technology.

Ethernet over Copper (EoC) bandwidth starts at typically 2 Mbps and goes up to 200 Mbps in some areas. This not only gives you a way to grow your bandwidth incrementally beyond T1, but may delay fiber installation indefinitely. The one limitation of EoC is that it is distance limited. How far you are from the office where your copper bundle is terminated determines the bandwidth that is possible. That office also needs to have EoC equipment available.

Have you outgrown your T1 line service or have an immediate business need for bandwidth in the 45 Mbps range? If so get pricing and availability of DS3 bandwidth services, including Ethernet over Copper if available.



Photo of BNC connector courtesy of Wikimedia Commons.