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Switching Network in Telecommunications

The direction of this paper is to describe a telecommunications switch and show its purpose and multitasking abilities.  This paper will use the AT&T 5ESS Switch to give a real world example of a top rated telecommunications switch.  The end result will be an understanding of how a switch works and what it can do.  Also, it will show why the AT&T 5ESS Switch is #1 in today’s telecommunication world.
In today’s world a person should be able to pick up his phone and dial to almost anywhere in the world.  Without knowing anything about switching, one would think that there phone would have to have a separate line to everyone other phone in the world.  This would be quite a lot of lines into just one phone and know that this is an impossible scenario.  This is why the switched network was developed.  A switched network brings each subscriber line into a centralized switching system, where connections are made for each call.

The earliest telephone switches were hand-operated – that is, they required a human operator to make connections by plugging circuits into a switchboard.  When the customer “rang” the central office, the operator scanned the switchboard and connected the caller by plugging into the requested line.
The invention of the mechanical switch came about in the late 1880.  Now, the mechanical switch replaced the human operator, who handled the physical connections.  These early switching systems were based on the analog technology that was state-of-the-art electronics at the time.  By the mid 1970’s digital technologies were being introduced into the core of the public switched network.  Digital switches fully capitalized on the strength of the computer revolution by routing both voice and data through the switch in the form of 0/1 binary coded information, which can be moved through the switch in a very short period of time.   A single digital switch typically serves anywhere from under 1000 to over 100,000 subscribers.
The typical digital switch has four components: the central processor, the switch matrix, a range of peripherals, and input/output controllers.

Central Processor – The central processor controls call processing activities.  Examples of some activities are assigning time slots and administering special calling features such as call forwarding.  The central processor is also responsible for directing system-control functions, system maintenance, and the loading and downloading of software.  The central processor is usually duplicated within a  switch to ensure reliability.  If the “hot” processor should develop a problem while a call is being processed, the system automatically shifts to the standby processor – without the caller noticing any interruption of service
Switch Matrix – This is also referred to as the network.  It handles the actual connection of calls to their destinations.
Peripherals – These convert incoming voice and data signals into the digital format used by the switch and perform some low-level call processing tasks.  There are usually a range of peripheral modules to interface the range of lines and trunks coming in from the network.
Input/Output Controller – This system provides access to the switch for billing, maintenance, loading of software, and routine operations and administration.
The primary function of a switch is    Picture – lucent.com/netsys/5ESS/family
the transmission of voice or data.
When a local call is placed, a digital
switch performs multiple call processing
Call Detection – Detection that the telephone receiver is off the     hook.
Dial Tone Provided – Provides dial tone to the caller.
Digit Collection – Collects the dialed digits.
Digit Translation – Translates dialed digits into a call number.
Call Routing – Routes the call to its destination.
Call Connection – Connects parties.
Audible Ringing/Ringback – Signaling the called party by audible ringing, and the calling party by ringback.
Call Termination – Disconnecting and terminating the call when a party hangs up.
How does a switch accomplish all these functions?

The answer is Software.  The switch is a large scale, real time software based system.  The switch itself, works through commands located in the software applications used.  Software is the guiding command that makes the switch execute its processes.
Now that the function and purpose of the telecommunications switch has been established, lets look in detail at the AT&T 5ESS digital switch.   This switch is the leader in the market of Service Providing switches.  It handles all forms of media transmission and is setup to be expanded very easily.  With its flexible architecture it is easy to see why the AT&T 5ESS Switch serves over 70 million subscribers in more than 40 countries.
Picture of 5ESS – http://www.lucent.com/netsys/5ESS/family
The first 5ESS Switch was installed in Sugar Grove, Illinois in March, 1982.  It is a digital switch that provides local service, ISDN, Operator and International Gateway services, and a host of custom business and residential service offerings.   The new digital switches replaced earlier electromechanical or analog switching systems.

The 5ESS Switch is the most flexible digital exchange for use in the global switching network.  The 5ESS equipment switches ISDN voice and data, local voice calls, long distance calls, Internet access, wireless PCS, Advanced Intelligent Network (AIN) services, interactive video and multimedia services.moving any media on the public switched network.
The 5ESS Switch architecture is a modular, distributed architecture with an administrative module, a communications module, and a varying number of switching modules that provide the major processing power in the total communication system.
Picture – http://www.lucent.com/netsys/5ESS/5esswtch.html
A big advantage of the 5ESS Switch is its modular design.  This modularity allows for ease of implementing continuing enhancements and allows service providers the ability to change their communication network quickly.
Telephone administrations are often concerned with:
Increasing busy hour call completion capacity
Minimizing floor space requirements
Enabling growth in small increments
Integrating multiple applications in one exchange
Reducing power consumption and operational costs
The 5ESS Switch architecture and software addresses each of these concerns.  Advanced services from the 5ESS Switch can be provided to all customers wherever they are located.

Picture – http://www.lucent.com/netsys/5ESS/5esswth.html
The newest 5ESS Switch out on the market is the 5ESS-2000 Switch, which provides local and long distance, wireless and wireline, custom and national ISDN and multiple advanced services.
The 5ESS-2000 Switch continues to handle the changing and increasing needs of customers, providing a multi-services platform that gives service providers the ability to offer subscribers a wide range of services. These services include wireless services (both cellular and PCS), Internet and on-line services access, Advanced Intelligent Network (AIN) services, multimedia services, local and long distance services – all from a single switch.
The 5ESS-2000 Switch stands alone as the only platform in the industry capable of simultaneously supporting any combination of wireline, voice, data and video services off the same switch.  This unique concept – what we call the AnyMedia Network Solution – enables the 5ESS-2000 Switch to deliver the total strategic flexibility and cost-effectiveness that a business requires and that no other platform can match.

Picture (5) – http://www.lucent.com/netsys/5ESS/anymedia/index.html
Whether a service provider modernizes switches, flattens a network hierarchy through consolidation or builds an entirely new network, 5ESS-2000 Switch is an ideal choice.  As the most cost-effective, flexible switching platform on the market today – and the only switch to offer AnyMedia capability – it can meet short-term market needs while providing a solid foundation for long-term business growth.
With this unrivaled AnyMedia Platform flexibility and modular, distributed architecture, the 5ESS-2000 Switch is being used throughout the United States and internationally.  In fact, all major U.S. telephone companies and many emerging Service Providers have placed 5ESS-2000 Switch and its product family at the heart of their new flat, more flexible networks.
The AT&T 5ESS Switch can do multiple functions that offer a lot to subscribers, but what good is it if the system is not reliable.  Residential and business customers expect that their telephone services will be consistently up and running, under any conditions short of the occasional catastrophic natural disaster that destroys the actual facilities that deliver their service.  The phone is now perceived as more than a convenience.

Network reliability has become the industry watchword – and with good reason.  A series of lengthy and extensive outages in 1991 led the Federal Communications Commission (FCC) to scrutinize the reliability issue more closely.
AT&T 5ESS Switch system reliability is achieved by complete duplication of all critical system hardware and software elements.
The FCC quality monitoring process has shown the 5ESS Switch is highly reliable, in fact the 5ESS-2000 switch is four times more reliable than its nearest competitor.  Today the 5ESS switch is considered the workhorse of the public telecommunications network in the United States with its lower life cycle costs and its proven record of reliability.
Today’s digital switches have allowed telecommunications to meet the demands of both residential and business customers.  No longer is telecommunications a convenience.  It is a necessity.  Businesses need to be able to transmit and receive information in order to keep them competitive in today’s world.  People need access to 911 emergency services and hospitals and doctors need access to lifeline services for the care of patients.

As the world continues to change and advance technologically, the demands are going to continue on the telecommunications world.  With this in mind, a company would want to have a switch in place that can grow and change, both easily and inexpensively, with the demands of the market.  The AT&T 5ESS-2000 Switch is the right tool for this job.  A key strategic advantage of the 5ESS-2000 Switch is its modular design.  This design allows ongoing enhancements to be added easily and cost-effectively, but more importantly, it enables quick changes to communication networks to accommodate market, regulatory or technology changes.  I feel that the AT&T 5ESS-2000 Switch is the best switch on the market today.  It is set up to meet current and future needs of the subscribers it services.  It takes a lot to be considered the best, but the main reason noted should be that the AT&T 5ESS-2000 Switch serves over 70 million subscribers in more than 40 countries.  This accomplishment is what makes the 5ESS Switch #1.


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Switching Network in Telecommunications

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