FREE ESSAY ON SWITCHING NETWORK IN TELECOMMUNICATIONS

SWITCHING NETWORK IN TELECOMMUNICATIONS

SWITCHING NETWORK IN TELECOMMUNICATIONS
(AT&T 5ESS SWITCH)
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. 
SWITCHING
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
to establish connections between 
telephones and data equipment for 
the transmission of voice or data. 
When a local call is placed, a digital 
switch performs multiple call processing 
functions. These functions are:
? 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.
AT&T 5ESS
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.
RELIABILITY
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. 
CONCLUSION
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.
Bibliography
ENDNOTES
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IBID
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Unknown. AnyMedia Platform. Accessed on April 17, 1998,
http://www.lucent.com/netsys/5ESS/anymedia/index.html.
Unknown. The Technology of Telephony. Telephony 101, accessed on March 23, 1998.
http://www.nortel.com/broadband/reference/telephony_101.html p.75.
Unknown. Switching & Transmission: How reliable is the public network? Electric Library,
accessed on April 17, 1998,
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