Can you explain the last mile for communications technologies? What last-mile communications media can enterprises choose from?
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The last mile refers to the final leg of a service, loop or telephone line from the local central office (CO) serving that customer's address. Often T1s and Primary Rate Interfaces (PRI) reside over a carrier network to the local exchange point or the local CO serving that customer address. So in reality, there are two providers or two segments of the circuit -- but only when addressing copper. Carriers offering fiber may bypass the local carrier or telephone company (TELCO) completely.
Then there's cellular. Banks use remote ATMs connected to a router with a cellular card, because the ATM is located too far from a CO and extending service is too costly. Satellite is still used by many organizations. For companies using private wireless point-to-point (unlicensed), they may be bypassing the local CO in one location but not all locations, unless they have fiber serving their main location that branches out using satellite or private radio.
In short, media enterprises have a variety of options when it comes to choosing a means by which to cover last-mile communications. The address of the company still determines which type of service will be used. This goes back to the old wire centers that use vertical and horizontal (V&H) coordinates, and these coordinates dictate what services are available to an enterprise. That's something many don't understand until they start shopping around for services. AT&T and Verizon are offering wireless plain old telephone service (POTS) to rid themselves of last-mile copper they know is too costly to maintain. Unfortunately, most last-mile service originates from the local CO or telephone company. So if you're not feeling stuck, you should be.
For any business that is moving or building, I suggest finding out what services are available at the address (this is sometimes called qualifying the address). For all businesses, the question is to decide which service makes the most sense to adopt now. The last-mile communications media are: copper, Ethernet via copper or fiber, fiber, satellite, cellular, private radio spectrum (unlicensed) and, in some cases, licensed private radio spectrum. Copper wire-line is still in supply, but fiber reigns as the best choice. When you get into cellular and satellite, you really need to fight latency. When you deal with remote locations, you will likely be fighting cost and giving in to latency.
For more information:
- PSTN and the last mile: Have telecoms moved on?
This was first published in October 2013