Road Map to VoIP Transports and Services

Let’s face it — telecommunications can be daunting to those who have not given much thought as to how their  voice gets from their  phone’s handset to their  Aunt Matilda  in Dubuque. Be that  as it may, the technology between you and Aunt Matilda  is simply amazing.

This chapter introduces you to the  wonderful world of networks, transports, and transport services. Here you discover what a CSI is (besides a great family of television shows) and  why you should even care. Before you are finished with this  chapter, you’ll have  a good  grasp of things you didn’t  even  know you needed to grasp. (Spooky,  huh?)

This chapter lays the  groundwork for Chapters 5 through 8. Here you find the  conceptual framework that lets  you make sense of different ways of transmit- ting data, such as broadband, dedicated lines,  and  cable. You also  discover why packet-switched communications methods are much better than tradi-  tional circuit-switched methods.

If you don’t  want  to take  a peek  behind the  curtain of telecommunications, you don’t  really need to read this  chapter — and  you don’t  even  need to feel guilty about it! That’s  not  an effort to discount the  information provided here,  but  a recognition that the  information may not  interest everyone. You can safely skip this  chapter and  come back  to it later when you finally develop a healthy curiosity as to why things work the  way they  do in the telecom world.


CSI: Telephony

All types of networks operate within a much larger  structure known  in the telecommunications industry as a carrier services infrastructure (CSI). The carrier services infrastructure is an abstract concept for most people. As you begin  to discover the  various VoIP network types (such as DSL or a T1 line), it’s essential to know about each network type’s  underlying CSI. Whatever network type  you may choose to use for your  VoIP, it is always a subnetwork of a larger  CSI. We get into the  details of each CSI later.  For now, just  focus  on the  fact that there are five CSIs through which all public and  pri- vate  communications travel.

The different CSIs are theoretically owned by the  carrier companies that lease the  various network transports and  services. But in reality you can’t own something that exists largely  in abstract terms. A good  analogy is the  National Football League.  Is it owned by the  NFL? We could say that it is. But to be more  correct, we might  say that it’s owned by all the teams that make up the  NFL. And an individual NFL team exists by virtue of the  NFL granting (selling and  approving) a team franchise.

Truth be told,  the  NFL doesn’t own much of anything in the  physical sense
of the  word.  Football fields are owned by their respective teams. NFL players are said  to be owned or at least under contract by their specific team.

At the  same time,  the  NFL is not  totally out  of the  picture. We hear lots about the  NFL regarding regulatory measures and  enforcement actions they  may take against teams and players in the NFL. The NFL sets the rules for all teams to operate collectively. All the  football stadiums together, with the  players and  the  games they  play, form the  NFL.
Like the  NFL, CSIs are not  owned by any specific carrier company. Each car- rier  has  a certain amount of physical network transports (lines) within one or more  of the  CSIs. Today,  more  than a thousand different carriers operate in the  domestic United  States. Many are local and regional. Others are national and even international. Like the various NFL teams, the carriers compete with other carrier companies for business from the  corporate marketplace as well as the  consumer marketplace. They  do this  by leasing transports and  net- work services from a given CSI to their customers. Everyone needs carrier services and most  companies have a diverse set of telecommunications needs.

All five of the  CSIs relate to the  telecommunications industry, but  each CSI contains different types of network lines  and  services. In the  case of the wire- less  CSI, which ultimately uses lines  at its core,  there are no lines  for the  cus- tomer in the  physical sense of the  word.  But there is a frequency spectrum and  frequency channels, just  like the  various station channels that operate
on radio.

It pays  for you to know your  VoIP network options across all five CSIs, but don’t  expect your  carrier to keep  you up-to-date. If you’re  near your contract renewal anniversary, you most likely will hear from several carriers about the  latest and  greatest services now available. If you’re currently using  a nonVoIP carrier company, your  carrier won’t have  much of an incentive to talk to you about VoIP because it significantly reduces your  dependence on conventional telephony networks.