The city’s current venture into high-speed internet transmitted by buried cables looks dated in a world with wireless, but a basic understanding of what the information delivery system is, how it works and the benefits generated by a 100 percent fiber network versus alternative methods may give insight as to why it’s a priority.
Although universal wireless internet and information sent by lasers over thin air may sound appealing, experts say a fiber infrastructure is the immediate future of fast internet.
“You can send more information over a strand of fiber than you can an equivalent strand of copper or than you can send through the air — and it’s a lot more information,” said Steven Wallace, enterprise network architect for Indiana University.
“It’s hard to conceptualize how much more information. It’s not infinite, but it is darn close.”
The speed of light
So how does it work?It’s a mistake to equate the fiber used in an internet infrastructure with the fiber optics used in novelty lamps, even though both strands use a similar phenomenon called total internal reflection to transmit light.
Wallace said fiber was introduced as a material for mainstream communication in the 1970s. Several components are within each fiber-optic cable.
At the center lies a filament of glass one-tenth the width of a human hair that directs the actual transmission of information. That glass core is contained within a slightly larger tube made of a different glass material. That different glass — and the nearly nonexistent space between those glass strands — helps light travel through the core.
“Because the center piece is so small, the light doesn’t really bounce around, it just follows it smoothly,” Wallace said.
“It acts like a wave guide. You have very little light loss per unit of distance, and the signal integrity over that distance is much greater than over copper or the type of stuff you see in those lamps at the novelty store.”
All of that is contained within several layers designed to protect the fiber cable. A cable may contain several of these strands of fiber, allowing for a greater use of the space within an underground pipeline, known as a conduit.
The bursts of light that travel through the fiber strands are encoded with the information someone wants to pull up on their device. It could be anything from a Netflix original series to a patient’s medical history to an order for a large pepperoni pizza. First, the light makes its way from the servers that hold a website’s information through that fiber core. On its way to a user’s device, that light passes through a carrier hotel, which is a physical building that allows internet service providers to locate and power their transmission equipment. Carrier hotels also allow for tenants, service providers, to cross-connect their networks.
If the distance between the carrier hotel and the user’s device is too great, the signal may weaken and die. To regenerate that signal, providers locate devices — called nodes, cabinets or repeaters — throughout neighborhoods, and fiber requires fewer of these than copper systems do.
In a fiber-to-the-home model, that reinvigorated signal follows a single strand of fiber into the user’s house and is translated by a customer’s hardware into the information that’s on your desktop or beamed to your phone over a wireless router.
Both the upload and download information travels over that same hairline strand. By altering the light’s wavelength, fiber developers can turn those individual strands into a two-way road. Essentially, light containing upload information is sent using a different color wavelength than light carrying download information.
That’s different from the fiber systems used by larger consumers, such as Indiana University and major technology businesses. Wallace said when university users connect to the fiber system, there are two strands of fiber — one for uploading and one for downloading.
Even with the differences between commercial and residential fiber internet, both systems are noticeably different from copper systems. IU Associate Vice President for Networking Dave Jent listed some of fiber’s benefits compared with other systems, such as copper: increased speed and bandwidth, the ability to travel greater distances without costly signal regeneration, a natural resistance to outside interference and more manageable maintenance.
“Despite what people say, it is as reliable as copper, if not more so. ... There’s a Kevlar coating around it; there’s usually a metal barrier inside. It’s more delicate than this honking thing,” Jent said as he dropped a copper cable several times larger and heavier than a fiber-optic cable to illustrate his point. “If you cut this, it will take a bit of time to repair.”
Existing infrastructure
Fiber, as a transmission system, provides larger amounts of information at faster speeds, but that’s not to say the copper system that already exists beneath Bloomington should be discounted.Comcast recently unveiled its plan for gigabit-speed service in Bloomington, which runs off an existing hybrid infrastructure. Comcast’s system is partly fiber and partly copper coaxial cable. The system starts with lines made of fiber-optic cable close to the provider, but once the transmitted light hits a certain point closer to the consumer (not quite to their door), the information is instead transmitted by the sort of copper cable that telephone lines use.
To most efficiently use the existing system, Comcast compresses the information running through the lines so that it can move an equivalent amount of information over copper at the same speeds as fiber. A signal run through copper lines has to be amplified more often than a signal run across fiber, Wallace said.
“That copper cable can only be so long before you have to regenerate the signal, and the higher the data rate you were using on the signal, the more frequently you had to regenerate the signal. If you had a few megabits per second over copper, maybe every couple of miles you would have to have electronics boost the signal. Fiber, you can have tremendously greater capacity. Terabits of information. And those terabits of information can go for 100 miles before anything has to boost the signal.”
Although one benefit of using the old system is avoiding installation and construction costs, Comcast will use fiber in its new infrastructure installations.
“If you look at the apples-to-apples comparison, there is nothing in the traditional copper — or even the wireless world — that’s as effective,” Jent said. “I don’t think there’s anything to compare to fiber.”
“The fiber itself is going to be reused by more and more sophisticated electronics,” Wallace said. “You’re going to use the same fiber for decades. In fact, they don’t know how long because we haven’t seen fiber degrade substantially.”
Wallace said fiber likely won’t become obsolete or outdated. Instead, fiber is so future-proof that it will outlast the electronics that currently use the system as internet speeds increase. Consumers will have to upgrade their electronics long before upgrading the fiber itself, according to Wallace.
“Another way to look at it is you’ve got a road to your house, and today you’ve got a gas car,” he said. “Tomorrow you might be driving a hybrid, and then after that you’ll be buying electric. It’s the same road. And with fiber, you’re building a data highway. Over time, you’re going to upgrade what vehicles you run on that data highway, but you’re not going to update the fiber.”
©2017 the Herald-Times (Bloomington, Ind.) Distributed by Tribune Content Agency, LLC.
