LAN, MAN and WAN speeds continue to rise as content demands more and more bandwidth. This is increasing pressure on both copper and fiber based telecommunication networks for more frequent speed upgrades. Let’s take a look at what the options are for both traditional TDM (Time division Multiplexing) and IP (Internet Protocol) networks.
The Legacy of Copper Telecom LinesCopper has been the mainstay of electronic communications, starting with the telegraph and then the telephone networks. The telegraph, of course, is long gone. The telephone is undergoing a technology shift where voice is becoming a converged network service. With the implementation of 4G LTE wireless, even cellular phone will soon move away from voice only channels to integration with data.
Clearly, analog POTS (Plain Old Telephone Service) is in its twilight years. What will remain for decades to come is its installed base of twisted pair copper lines that connect to nearly every building, commercial and residential. That copper still has value because it can transport digital signals as well as analog.
Digital T1 Lines
The oldest digital protocol for data transmission on twisted pair copper (not including telegraph) is still going strong. It’s the T1 line used for telephone trunking, point to point data, and dedicated Internet connections. T1’s history is that it was developed to transport multiple phone conversations digitally using existing telephone cabling. T1 can transport service over wide areas using signal regenerators to clean up the signal every 6,000 ft. You can get T1 nearly anywhere you can get landline phone service. The one limitation is its 1.5 Mbps bandwidth.
While 1.5 Mbps used to be considered broadband, it’s no longer adequate except for PBX telephony, casual Web access, email and point of sale credit card verification. This bandwidth is similar to 3G wireless. Wireless is rapidly moving to 4G wireless, with speeds an order of magnitude higher. Wired services are also moving to 10 or 15 Mbps as a minimal requirement.
Bonding T1 Lines & Ethernet over Copper
T1 is enjoying continued usefulness by bonding the bandwidth of multiple T1 lines to make one larger service level. This is practical up to 10 or 12 Mbps, but gets too expensive and hard to find available bundles of unused copper pair above that. What’s needed is a different technology that gets more bandwidth out of the same copper.
That technology is now available and called Ethernet over Copper or EoC. Ethernet is a departure from T1 in the way the bits are organized on the line, but serves the same purpose. It uses exactly the same copper pair cabling with multiple pairs bonded to increase bandwidth. The differences are that EoC is available in increments from about 3 to 45 Mbps and it is distance limited. Near the central offices, high speeds are available. A few miles away there may be no EoC service at all. In between, there are different service levels possible.
There have been some major advances in transmission of data over copper pair wiring, with some installations supporting bandwidths as high as 100 or 200 Mbps. These are uncommon. Another copper technology, Cable broadband using coaxial copper cables and a modulation scheme called DOCSIS 3, can reliably deliver 100 Mbps or more bandwidth. Even 1 Gbps is not unheard of, although not that widely available. Another service called DS3 or T3 offers 45 Mbps over a pair of coaxial lines where available.
Fiber Optic Services for Unlimited Bandwidth
What really gets the job done at higher bandwidths is fiber optic cabling. Fiber bandwidth is nearly unlimited, especially when wavelengths are bonded to create very large services. Like, copper, fiber also has a legacy history and a newer technical approach.
Traditional fiber optic service is based on a telephony standard called SONET (Synchronous Optical NETwork). Familiar service levels are OC-3 at 155 Mbps, OC-12 at 622 Mbps and OC-48 at 2.4 Gbps. Higher levels include 10 Gbps and 40 Gbps.
Ethernet over Fiber (EoF) is a Carrier Ethernet service like EoC, but using fiber rather than copper transmission. Fiber Ethernet is highly cost competitive and readily available from 10 Mbps on up to 10 Gbps. Today’s most popular service levels are 100 Mbps Fast Ethernet and 1,000 Mbps Gigabit Ethernet (GigE). In some areas, 100 Gbps service is available to businesses.
Wavelengths Options
Fiber enjoys another advantage over copper in that it supports multiple 10 Gbps wavelengths through a process called WDM or Wavelength Division Multiplexing. This means you can run different protocols on completely separate wavelengths within the same fiber strand. This provides a high degree of flexibility for financial institutions and others with demanding applications.
As you can see, there are a wide variety of options on both copper and fiber transmissionall currently available. What works best for your organization is a function of application requirements, scale and budget. You’ll likely have multiple technologies and multiple vendors to choose from.
