Switching Network In Telecommunications Essays - Alcatel-Lucent

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