Are There Any Limitations To DSL Service?

While we offer 100 Mbps to customers with fiber to the home, our current limit on DSL is 20Mbps. Customers often ask why can’t we push out 100 Mb to their home over copper lines, like we can provide over our fiber optic lines.  We are also sometimes asked by DSL customers why they may not always be seeing the full 20Mb they are allocated on our servers. This article is an attempt to answer these questions, by explaining what some of the factors affecting DSL service are.

Many of the limitations associated with regular DSL service lie simply in the physics or nature of metals.

Copper is of course a metal, and although the data being sent over the line is a digital signal, it still travels electronically as a wave over the metal line. However, a real wire is always a more superior way to deliver data than wireless, for obvious reasons. Any kid who has picked up a tin can with a string attached to it knows that.

Distance

Signals degrade over long distances. That is just a law of nature. Copper is a good conductor, but it’s not a perfect conductor. Inside any metal line, there is resistance as the electronic waves travel through the metal. Because of this fact, there is a limit to how far DSL can travel from the main telephone switch. Usually it can only go 2 or 3 miles at the most before you need to build another office to repeat that signal. A regular analog telephone conversation can be pushed out much further, because signal degradation is not as critical, but to deliver internet data , with the digital packets being sent in very precise, technical ways, any kind of interference, loss of signal or degradation is going to cause problems.

The wonderful thing about  fiber optic cable is that it overcomes many of the limitations of metal. Fiber carries an all-digital signal, so is better suited to today’s digital communication devices. Also, there is no interference from electric lines or magnetic fields like you experience with copper, so the signal is clearer, which will result in a better transfer over great distances. There is no resistance in the fiber optic cable like metal lines have, so the signal can travel infinitely, because it’s light, not an electron flow, so we can now serve customers who live far away from the central phone office with products like broadband, which is vital in the rural areas. Fiber optics will open up whole new markets of people who previously were too far to pick up a DSL signal over copper.

Anyway, with that said, it is possible that in an all copper network, homes closer to the main office would probably get better DSL signal than homes very far away from the office. In Eagle Mountain, this is not usually a problem—we have fiber to all of the neighborhood nodes or DSLAMs (digital subscriber line access multiplexer, pronounced dee-slam). About half of the homes in Eagle Mountain now have fiber to the home, but even where the final loop from the DSLAM to the home is still copper, that is just a very short little section of copper, so distance doesn’t often come into play. But, in our more rural exchange areas in Idaho, where a farm might be 15 or 20 miles from our central office, without fiber opics, that home could not get DSL. Homes at the edge of our range of 2 or 3 miles from the DSLAM are not going to be able to get our full 12Mb or 20Mb that we offer on DSL, but they might get a portion of that.

 Signal Frequency

Did you know that DSL (which stands for Digital Subscriber Line) was originally developed to deliver video over a telephone line? Back in the 1980’s, the telephone companies were looking for ways to use the extra bandwidth that was unused in their copper lines. A typical copper telephone line has about 1100KHz of bandwidth frequency available. The plain old telephone service was only using a fraction of that frequency—a maximum of 3.5KHz. We already had this fantastic network laid to each home, and so thought we could use all the extra space in the line to deliver television digitally to the customer. (Telephone companies are still looking for cost-effective to do this in 2012.) Anyway, luckily for telephone companies, a fantastic thing came along in the mid 90’s called the Internet. Suddenly, a real customer need developed for DSL—we could use that extra frequency to deliver data to connect people to other computers all over the world. DSL as we know it exploded into various different specs to deliver data more effectively. So, the DSL signals travels on the same line as the telephone signal, but at higher frequencies, and it takes up a lot more of the bandwidth in the line. (This is why we still hand out those DSL filters, so you won’t  hear the high-frequency noise of the DSL waves on your telephone.) However, there is still a technical bandwidth limit on just how much you can fit through the line at once, due to the nature of waves.

Wire Gauge

Very simply put: the larger the copper wire, the more physical space there is available to pump signal through. While gauge is rarely a problem with lines that we have installed ourselves, we have run into problems in houses or neighborhoods where a builder, developer or homeowner originally laid the line themselves. Let’s face it—developers and contractors like to cut costs wherever they can, and unfortunately some home builders didn’t always have the customers future bandwidth needs in mind when they laid the telephone line to the home. We do what we can once we take ownership of these lines to overcome these problems, but often they are hidden, since these lines have been buried for years, and there were no maps or records of what is in the ground in some older neighborhoods.

Splices

A splice happens when you join two lines. Splices are done by humans, and so aren’t always perfect. Thus, the more splices in a line, the less effectively it delivers data. In Eagle Mountain, there may still be some older homes with lines containing  splices made a long time ago by people who were not as well trained as our techs are today. We correct these when we find them, but if you are not getting your full bandwidth (say you are only getting 15 Mb when you signed up for 20Mb) a faulty splice somewhere near your home could be the problem.

Condition of the Loop

A loop refers to the last portion of the copper line between a neighborhood node and the homes. As already stated, some end loops are in better condition than others, depending on how they were constructed.

The Cloud/Internet

Many times, people will assume that their home broadband service is being slow, when in fact the bottleneck or slow speeds are somewhere else in the world. When you are sitting at your home computer, and you connect to a remote internet site, your connection to that computer, or server is taking various routes around the world, with a single request for a download being passed through ten, twenty, or more, different companies and ISPs. (Internet Service Provider.) There really is no way to know what routes your request has taken. The server hosting the website is usually in another state–maybe even in another country. The internet is simply millions of computers, servers and routers connecting, and who knows what condition their lines are in. The server you are reading from might only be connected to their local ISP with a 1.5Mb T1, or even worse. You, and us as your local broadband provider, have absolutely no control over what happens in the cloud. Even if you are on a 100Mb connection from your home to the telephone switch, if you are busy talking to a web server that is only connected to the internet by a 1.5Mb connection, the fastest speed you are going to transfer data from that website is 1.5Mb. All you can control is how much speed you subscribe to at home from your local ISP—give yourself the best chance to have a good experience online.

Bottlenecks

The limitations associated with delivering broadband is not only the physical line—the real limitation is the processing power of the routers, servers, or electronics at each end. When you connect to a remote server, the speed at which you can talk to that computer depends on how many conversations that server (or site) can handle at once. Even companies like Facebook, who invest millions of dollars on server farms to host their sites, have times when their service crashes, or slow days because the electronics on their end can’t handle the number of connection requests coming from people all over the world. There may be a bottleneck in the backbone somewhere along the line too—not enough fiber connections or processing power on some remote router on a particular line between Las Vegas and Seattle that some upper tier carrier has subscribed to.

Customer Internal/Home Network

Although customers hate it when their ISP claims the problem is inside their home, the reality is, for a majority of connection problems and trouble tickets, the problem is either user error, or faulty or incorrectly networked equipment inside the home. The usual suspects for slow speeds are modems and wireless routers. No matter what the manufactures claim, cheap consumer grade switches and routers, especially when they are broadcasting a wireless signal, do not always deliver the speeds they claim. To get the best out of your home router, wire each device to your router with a CAT5 ethernet cable. This will make a huge difference to your speeds. A more expensive router with more processing power will also make a difference, especially if you are connecting multiple devices simultaneously and each kid is trying to stream Netflix on a different device.

Despite any of these limitations, DSL is still a premium product, and after fiber, absolutely the best way to deliver consistent broadband data to any home. In Eagle Mountain we recently upgraded from ADSL2+ to VDSL so that we could crank up both the download and upload speeds to copper customers, and the technology to distribute DSL will keep improving, opening the way for more bandwidth. Potential customers often ask us when we are going to install fiber to their home, and they say they will switch to our service once fiber is there. The irony to this, however, is that often once the fiber is installed, they usually end up requesting either our 8Mb, 14Mb, or 20Mb service—all of which are currently available on regular DSL service. Only our 30Mb and 50Mb speeds are exclusive to fiber to the home customers.

About Brigham Griffin
Brigham Griffin, Marketing Director for Direct Communications, resides in rural Idaho, and has been with the company since 2005. Brigham has an MBA from the University of Utah, and a BA in Communications from Brigham Young University. He also serves as an adjunct professor of marketing at Idaho State University.

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