Definitions of Voice and Data Network Services Acronyms and Common Terms
The following are brief definitions of acronyms and terms found on the PINS website and in voice and data telecommunication services in general. More detailed explanations of these terms can be found on Wikipedia, Dictionary.com, and similar sites.
The bandwidth or speed used to deliver voice, Internet and data services can vary dramatically. Typically quoted in units of kilobits per second (K, KB or KBS) or megabits per second (M, MB or MBS), the larger the number, the faster the response time and the more phones and computers the connection can handle, as well as the larger the cost. The list below includes the most common methods of delivering "high speed" services, also sometimes referred to as "Metronet" services. Each method typically requires different hardware and software protocols to send and receive data packets.
- DSL (Digital Subscriber Line) - This is the slowest of the so-called "high speed" services. It runs over the same twisted copper pairs that deliver POTS lines and is most often provided to the enduser in the asymmetric mode (ADSL), where data can be downloaded from the Internet faster than it can be uploaded. Bandwidth is usually quoted using two numbers, e.g., 3MB x 768KB, where the larger number is the maximum speed at which data can be downloaded. The maximum ADSL is currently 10x1 MB. A less common symmetric mode is also available (SDSL/SHDSL).
- T1 - This is a symmetric line which also uses twisted copper pairs, but with a maximum bandwidth of 1.544 MB in both directions. T1 lines can also be bonded to provide greater bandwidth (2xT1, or twinned for twice the bandwidth, 3xT1, or tripled for 3x, and so on). Still greater combinations of T1 lines and bandwidth are available. For example, DS3 is the equivalent of 84 T1 lines.
- EoC (Ethernet over Copper) - This symmetric service also uses twisted copper pairs, delivering bandwidths of from 3 to 20 MB.
- Fiber-Optic (TLS) - This symmetric service uses infra-red radiation within glass fibers to carry data at a maximum rate of 100 MB. In addition to having the greatest bandwidth, fiberoptic service has the fasted response time from the Tier 1 providers in case of faiure, and it is also the most secure since information does not leak out of the fiber unless it is physically cut into.
[Note: Not all services are available at all locations.]
CLEC (Competitive Local Exchange Carrier)
Prior to the break-up of the Bell system telecommunication monopoly in 1984, only the regional Bell companies could deliver phone and Internet service. After the break-up, new companies were allowed to “compete” to deliver these services, although different regulatory rules apply to the descendents of the original Bell companies such as Verizon, which is referred to as a “LEC” (or “ILEC”) and the newer telecommunication companies, such as PINS, which is referred to as a CLEC.
In many client situations, the most cost-effective approach is to use the same T1 (or faster) trunk line to deliver both voice and data services. Typically, the number of phone lines being used at any given time and the Internet traffic is constantly changing as people pick up or hang up their phone, or upload and download large files over the Internet. It used to be the case that in order to prevent loss of voice quality as Internet usage increased at a site, clients had to dedicate a portion of the T1 bandwidth to be sure that their voice quality remained high, reducing their available Internet/data bandwidth all the time. However, new technology allows PINS to dynamically allocate bandwidth between voice and data, by programming the PINS router to "steal" bandwidth from voice channels which are not in use, giving your network the flexibility to maximize your Internet bandwith on the fly, without degrading voice quality as the balance between voice and Internet usage changes.
ILEC (Incumbent Local Exchange Carrier) - See CLEC
The INTERNET refers to the interconnected global set of cables and equipment used to transmit data from point-to-point via specific protocols agreed to by the regulatory agencies in each country. The Internet can be used to transfer data (text and graphics), e-mail and phone information, as well as display information via hypertext (world wide web, i.e., “www”).
ISP (Internet Service Provider)
Any telecommunication company that provides access to the global Internet, typically supporting data transfer and e-mail services.
The term local area network (LAN) is typically used to describe the network used to connect the computers at a single site of an organization.
LEC (Local Exchange Carrier) - See CLEC
NOC (Network Operations Center)
The facility containing the equipment needed by a telecommunications company to connect its clients to the worldwide phone (PSTN) and data (INTERNET) networks.
A dedicated local telephone exchange for a single office or company. The PBX connects to a CLEC or ILEC allowing all the phones in the office emanating from the PBX access to the PSTN.
POTS (Plain Old Telephone Service)
POTS lines are the traditional copper phone lines used to deliver analog phone service. If POTS service is delivered directly from the local central office, the phones will continue to work in the event of a power outage in the building, making them good choices for faxes, phones used for emergency service or elevators. POTS lines delivered via VoIP will not be functional during a power failure unless provided with independent, on-site back up power via a UPS.
PSTN (Public Switched Telephone Network)
The PSTN is the interconnected global set of cables and equipment used to transmit telephone signals. Originally an analog system, but now almost entirely digital.
A router is a networking device, or specialized computer, which allows software control of the data flowing to and from the INTERNET. Voice and data information can be separated by the router and forwarded to the appropriate device, i.e., phone or computer.
A server is typically a multiprocessor computer which is tasked for a specific purpose using appropriate software, such as handling web traffic for an organization (i.e., a web server).
SIP (Session Initiation Protocol)
A variety of signaling protocols are used to allow phones to be connected over the Internet using VoIP, including SIP and H.323. These protocols are programs which open, manage and close a connection between two phones located anywhere in the PSTN, and which can be configured by the telecom service provider to allow the end user access to sophisticated telephone services, such as call waiting, messaging centers, caller ID, etc, over VoIP.
See http://en.wikipedia.org/wiki/Session_Initiation_Protocol for a detailed technical description.
TDM (Time-Division Multiplexing)
The traditional method of delivering voice service over twisted copper pair wiring directly connected to, and powered by the telephone central office in that city, in contrast to VoIP, where phone service is delivered over the Internet.
See http://en.wikipedia.org/wiki/Time-division_multiplexing for a detailed technical description.
Service providers are organized roughly into three "Tier Levels" based on size and function. Tier 1 refers to the largest voice and data providers, Tier 2 to intermediate size providers and Tier 3, to the smallest providers. As might be expected, not everyone agrees on which service providers fit into which category, but there are some broad distinctions that can be made.
Tier 1 providers typically operate in all states and install, maintain and own the cables which carry the voice (PTSN) and data (Internet) information packets across the country, as well as internationally. All Tier 1 providers are interconnected using the highest speed trunk cabling available, which allows customers of one provider to make calls to another, regardless of location. Tier 1 providers include, e.g., AT&T, Global Crossing, Qwest, Sprint and Verizon Business, but takeovers and mergers have resulted in name changes and elimination of such famous telecom names as Bell South (now part of AT&T) and MCI (now part of Verizon Business).
Tier 2 providers typically provide the same basic services as Tier 1 providers, but they usually operate in only one region of the country, serving as a CLEC for a single LATA, or perhaps two or three contiguous LATA's. PINS is a Tier 2 provider and serves as a CLEC for LATA 132, which includes New York City and surrounding areas.
Tier 3 providers typically do not originate any services themselves, but rather act as resellers for Tier 1 and Tier 2 service providers.
VoIP service delivered over a DSL line (see VoIP).
VoIP (Voice over Internet Protocol)
Traditional phone service was delivered by the former Bell system using analog technology (such as the rotary dial) over copper wire pairs. When digital technology became available, phone companies began to digitize phone information, and developed the multi-tone pulsed system we are familiar with today, but continued to deliver the signal over copper pairs (now usually referred to as TDM). With the advent of the Internet and the ability to transmit digitized data packets of information via the Internet, phone companies developed methodologies (protocols) that would allow them to send voice information packets over the Internet, i.e., VoIP (and VoDSL). Today, regardless of whether you use an analog or a digital phone, the signal from the phone company is almost always transmitted as digititized packets.
VPN is a computer network within a network which is encrypted to provide an additional layer of security. This can be used to permit users who are physically outside the boundaries of a particular organization, access to the computers and servers on the other side of the firewall which protects the integrity of the boundary.
A wide area network (WAN) is typically used to connect several, physically separated local area networks (LAN) of a single organization, providing access to computers located at different sites for all authorized users.
[Note: These definitions are provided for convenience only. PINS is not responsible for the accuracy of any of the statements included.]
