Summer Training Report

on

“Broadband and Switching”

Undertaken at

Mahanagar Telephone Nigam Limited

Rajouri Garden,New Delhi

Submitted by :

Divya Bhatia

Mehak Gupta

About the Mahanagar Telephone Nigam Limited

MTNL was setup on 1st April 1986 by the government of India to upgrade the quality of telecom services, expand the telecom network, and introduce new services and to raise revenue for telecom development needs for India’s leading and one of Asia’s largest telecom operating companies. Beside having a strong financial base, MTNL has achieved the market share of approx. 13% of the Indian telecommunication networking with a costumer base of over 4.74 million lines.The government of India currently holds 56.25% stake is the company.

Scope of Training

Training is one of the essential parts of engineering studies as it provides us confidence and exposure to the real world problem.In my training I used my learned skills and saw how things work in real world. Now we are quite confident about our fundamentals as we have tested them during our project and have gained experience of working with discipline. Practical training provides us a view of professional and prepares us to face the upcomingchallenges.

After achieving the proper goal of the engineer has to enter in professional life.According to this life one has to serve an industry, may be public or privateor self own. for the efficient work in the field he must be well aware ofpractical knowledge as well as theoretical knowledge. Since we belong to theelectronic field it is really helpful to take training at a place that clears adoubt and inquisitively regarding.

TABLE OF CONTENTS

1. Broadband2. Various Technology of Broadband3. Features of Broadband4. Dial-UP Internet5. Switch Room6. Types Of Switch7. Router8. Internet Service Provider(ISP)9. Local Area Network (LAN)10. Internet

Broadband:-Overview

“An ‘always-on' data connection that is able to support interactive services including Internet access and has the capability of the minimum download speed of 256 kilo bits per second (kbps) to an individual subscriber from the Point Of Presence (POP) of the service provider intending to provide Broadband service where multiple such individual Broadband connections are aggregated and the subscriber is able to access these interactive services including the Internet through this POP. The interactive services will exclude any services for which a separate licence is specifically required, for example, real-time voice transmission, except to the extent that it is presently permitted under ISP licence with Internet Telephony.”MTNL has launch broadband services under Brand name Tri Band. The services shall be provided on the existing copper infrastructure, initially Broadband Internet Service, other services such as VPN, multicasting, video conferencing, video-on-demand and broadcast application shall also be added in future.

In data communicationsBroadband in data can refer to broadband network or broadband internet and may have the same meaning as above, so that data transmission over a fibre cable. cable would be referred to as broadband as compared to a telephone modem operating at 56,000 bits per seconds. However, a worldwide standard for what level of bandwidth and network speeds actuallyconstitute Broadband has not been determined..

In DSLThe various forms of digital subscriber line (DSL) services are broadband in the sense that digital information is sent over a high-bandwidth channel (located above the baseband voice channel on a single pair of wires).

In EthernetA baseband transmission sends one type of signal using a medium's full bandwidth, as in 100-BASE-T Ethernet. Ethernet, however, is the common interface to broadband modems such as DSL data links, and has a high data rate itself, so is sometimes referred to as broadband. Ethernet provided over cable is a common alternative to DSL.

In power-line communicationPower line have also been used for various types of data communication. Although some systems for remote control are based on narrowband signalling, modern high-speed systems use broadband signalling to achieve very high data rates

In videoBroadband in analog video distribution is traditionally used to refer to systems such as cable television, where the individual channels are modulated carriers at fixed frequencies. In this context, baseband is the term's anteyom , referring to a single channel of analog video, typically in composite form with an audio sub carrier. The act of demodulating convertsbroadband video to baseband video.Demand for Broadband is primarily conditioned and driven by Internet and PC penetration. It is recognized that the current level of Internet and Broadband access in the country is low as compared to many Asian countries. Penetration of Broadband, Internet and Personal Computer (PC) in the country was 0.02%, 0.4% and 0.8% respectively at the end of December,2003. Currently, high speed Internet access is available at various speeds

from 64 kilobits per second (kbps) onwards and presently an always-on high speed Internet access at 128 kbps is considered as ‘Broadband'. There are no uniform standards for Broadband connectivity and various countries follow various standardsThe estimated growth for Broadband and Internet subscribers in the countryenvisaged through various technologies is as follows:

Year Ending Internet Subscribers Broadband Subscribers

2005 6 million 3 million

2007 18 million 9 million

2010 40 million 20 million

Technology Options for Broadband Services

The Broadband Policy Framework visualises creation of infrastructure through various access technologies which can contribute to growth and can mutually coexist. Spread of infrastructure is a must for healthy competition and therefore it would be the endeavour of the Government that the telecommunication infrastructure growth in the country is notcompromised in any manner.

Various access technologies, inter-alia, are:

(a) Optical Fibre Technologies

The fibre optics technology can provide nearly unlimited bandwidth potential and is steadily replacing copper network specially in intra-city backbone networks. This is being deployed in commercial buildings and complexes and some metros or big cities having high-density potential broadband subscribers. Hybrid Fibre Coaxial (HFC), Fibre to the Curb(FTTC) and Fibre to the Home (FTTH) networks make use of fibre cabling into the last mile. The fibre based models are future proof as they are able to provide huge amounts of bandwidth in the last mile as well as provide a true IP and converged network that can deliver high quality voice, data and video.There are more than 4.5 lakh route kms. of optical fibre laid by BSNL /MTNL and more than 1 lakh route kms laid by private operators. Thespread of the networks of private service providers have to play animportant role in bringing the fibre to homes as well as the rural areas and they are expected to focus on it.

(b) Digital Subscriber Lines(DSL) on copper loop :

DSL has proved to be an important technology for provisioning of Broadband services through the copper loop. The owners of copper loophave to be given a high priority because their role is critical as keydrivers in the Broadband service market using DSL.There are more than 40 million copper loops in the country available with BSNL and MTNL out of which 14 million loops are in rural areas.Coppercable network of these operators is a combination of old and new cableand this makes provisioning of Broadband on all the available copperloop technically unfit . Therefore, around 25-30% of the remaining 26million loops, i.e. approximately 7 million loops can be leveraged for broadband service by BSNL and MTNL taking into account the condition life of copper cable and demand potential.

(c) Cable TV NetworkIt is noted that cable TV connection as last mile infrastructure reaches more people than even the telephone copper infrastructure and can be leveraged in providing cable operators a new business model while giving a stimulus to Broadband penetration.

(d) Satellite MediaVery Small Aperture Terminals (VSAT) and Direct-to-Home(DTH) services would be encouraged for penetration of Broadband and Internet services with the added advantage to serve remote and inaccessible areas.

(e) Terrestrial Wireless

Recognising that terrestrial wireless is another upcoming technology platform for Broadband, it has been decided in principle to de-licence 2.40-2.48 GHz band for low-power outdoor use on non-protection, non-interference and non-exclusive basis. Necessary notification shall beissued. Further, notification regarding deli censing 2.40-2.4835 MHz band for low power indoor permitting use of all technologies, which inter-alia include those based on IEEE 802.11b and 802.11g standards, has been issued.

(f) Future TechnologiesIn the changing technology scenario, there is a possibility of new options being used for provisioning of Broadband services. These technologies can also be utilised for provisioning of such services within the licensing framework of the service provider and the spectrum management policy of DoT.

Main Features of the Broadband Service

High speed data download for Broadband Internet data speed starts from 256 kbps to 2 Mbps

Simultaneous availability of Phone and Internet on the existing Telephone line ”Always on Internet”.

No call charges for Internet access.

High on Value Low on Cost’ Service.

24 Hours Help line and Technical support on phone.

Easy registration on phone and web. Telephone will continue to work even in case of power failure at subscribers end.

‘Use now and pay later’ in telephone bill. It provides a means to bill based on Volume of data downloaded It will provide Multicast Video Services, Video-on-demand etc in future Can share Broadband connection to create own LAN network i.e. more than one PC can be connected.

Broadband Communications:-A class of communication channel capable of supporting a wide range of frequencies, typically from audio up to video frequencies. A broadband channel can carry multiple signals by dividing the total capacity into multiple, independent bandwidth channels, where each channel operates only on a specific range of frequencies. The term has come to be used forany kind of internet connection with download speed of more than 56 kbps, usually some kind of DSL, e.g. ADSL. A broadband connection is typically always connected, in contrast to a dial-up connection, and a fixed monthly rate is charged, often with a cap on the total amount of data that can be transferred. Domestic broadband connections typically share a telephone line with normal voice calls and the two uses can occur simultaneouslywithout interference.

Communications Satellites The satellites use microwave radio as their telecommunications medium which are not deflected by the Earth's atmosphere. The satellites are stationed in space, typically 22,000 miles above the equator. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals.

Cellular and PCS Systems Use several radio communications technologies. The systems are divided to different geographic area. Each area has low-power transmitter or radio relay antenna device to relay calls from one area to the next area.

Wireless LANs Wireless local area network use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area. Example of open-standardwireless radio-wave protocol is IEEE 802.11b (wi-fi).

Dial-up Internet access

Dial-up Internet access is a form of Internet access that uses telephone lines The user'scomputer or router uses an attached modem connected to a telephone line to dial into anInternet service provider's (ISP) node to establish a modem-to-modem link, which is then used to route Internet Protocol packets between the user's equipment and hosts.The term was coined during the early days of computer telecommunications when modems were needed to connect dumb terminals or computers running terminal emulator software tomainframes, minicomputers, online services and bulletin board systems via a telephone line.Dial-up connections to the Internet require no infrastructure other than the telephone network.As telephone access is widely available, dial-up remains useful to travellers. Dial-up is usually the only choice available for rural or remote areas where broadband installations are not prevalent due to low population and demand. Dial-up access may also be an alternative for users on limited budgets as it is offered for free by some ISPs, though broadband is increasingly available at lower prices in many countries due to market competition.Dial-up requires time to establish a usable telephone connection and perform handshaking forprotocol synchronization before data transfers can take place. In locales with telephoneconnection charges, each connection incurs an incremental cost. If calls are time-metered, the

duration of the connection incurs costs. Dial-up access is a transient connection, because either the user or the ISP terminates the connection. Internet service providers will often set a limit on connection durations to prevent hogging of access, and will disconnect the user — requiring reconnection and the costs and delays associated with it. Technically-inclined users often find a way to disable the auto-disconnect program such that they can remain connected for days. This is particularly useful for downloading large files such as videos.Dial-up Internet access is offered through a number of Internet service providers (ISPs). MostISPs lease a set of telephone numbers, sometimes local, sometimes national, that dial intonetwork pipelines that feed into the Internet. Subscribers to the ISP normally pay a monthly or yearly fee. For this fee, the subscriber can access the Internet any time of the day or night to cruise the World Wide Web, send and receive email, participate in IRC chat rooms and USENET newsgroups.Before a person can subscribe to a dial-up service, he or she must have a computer and dial-up modem. A modem is an inexpensive component that fits into a free slot inside the computer.There are also external modems that sit alongside the computer, connected to the computer by a serial or alternate type cable. A telephone line feeds into the modem.The modem is controlled by software in the computer; for example, the Network Connectionsutility that comes with Microsoft Windows operating systems. Here you can setup a profile for the ISP, which will tell the modem what phone number to call and how to communicate with the dial-up service. The ISP itself provides this information.Upon joining a dial-up service, the subscriber chooses a username and password. Once themodem calls the phone number and makes a connection, a "handshake" takes place in whichinformation is exchanged between the computer modem and the remote server. The usernameand password is supplied by the modem. This grants the user access through the dial-up gateway to the Internet.Dial-up service is the least expensive but also the slowest type of Internet access.

SWITCH ROOM

A network switch is a device that forwards and filters OSI Layer 2 datagram (chunk of data communication) between ports (connected cables) based on the MAC addresses in the packets. This is distinct from a hub in that it only forwards the frames to the ports involvedin the communication rather than all ports connected. A switch breaks the collision domain but represents itself a broadcast domain. Switches make forwarding decisions of frames on the basis of MAC addresses. A switch normally has numerous ports, facilitating a star topology for devices, and cascading additional switches. Some switches are capable of routing based on Layer 3 addressing or additional logical levels; these are called multilayerswitches. The term switch is used loosely in marketing to encompass devices including routers and bridges, as well as devices that may distribute traffic on load or by application content (e.g., a Web URL identifier). Electronic SwitchesThe first Electronics Switching System were not entirely digital. The Western Electric 1ESS Switch had reed relay metallic paths which were stored program- controlled. Equipment testing, changes to phone numbers, circuit lockouts and similar tasks were accomplished by typing on a terminal. Northern Telecom SP1, Ericsson AKE, Philips PRX/A, ITT Metaconta, British Telecom TXE series and several other designs were similar. These systems could use the old electromechanical signalling methods inherited from crossbar and step-by-step switches. They also introduced a new form of data communications: two 1ESS exchanges could communicate with one another using a data link called Common channel interoffice signalling . This data link was based on CCITT 6, a predecessor to SS7.

Digital SwitchDigital switches work by connecting two or more digital circuits together ,according to a dialled Telephone Number. Calls are set up between switches using the Signalling System 7 protocol, or one of its variants. In U.S. and military telecommunication, a digital switch is a switch that performs time division switching of digitized signals. This was first done in a few small and little used systems. The first product using a digital switch system was made by Amtelco. Prominent examples include Nortel DMS-100, Lucent 5ESS Switch, Siemens EWSD and Ericsson AXE telephone exchange. With few exceptions, most switches built since the 1980s are digital, so for practical purposes this is a distinction without a difference. This article describes digital switches, including algorithms and equipment.

Switch designLong distance switches may use a slower, more efficient switch-allocation algorithm than local central office, because they have near 100% utilization of their input and output channels. Central offices have more than 90% of their channel capacity unused.

The structure of a switch is an odd number of layers of smaller, simpler sub switches. Each layer is interconnected by a web of wires that goes from each sub switch, to a set of the next layer of sub switches. In most designs, a physical (space) switching layer alternates with a time switching layer. The layers are symmetric, because in a telephone system callers can also be callees.

A time-division sub switch reads a complete cycle of time slots into a memory, and then writes it out in a different order, also under control of a cyclic computer memory. This causes some delay in the signal.

Packet switching in networksPacket switching is used to optimize the use of the channel capacity available in digital telecommunication networks such as computer networks, to minimize the transmission latency.

The most well-known use of packet switching is the Internet and local area network. The Internet uses the internet protocol suite over a variety of Link Layer protocols.

RoutersA router is a networking device that forwards packets between networks using information in protocol headers and forwarding tables to determine the best next router for each packet. Routers work at the network layer (layer 3) of the OSI layer model and the Internet layer of TCP/IP.

Port Switch

Internet service provider

An Internet service provider (ISP), also sometimes referred to as an Internet access provider (IAP), is a company that offers its customers access to the Internet. The ISP connects to its customers using a data transmission technology appropriate for delivering Internet Protocol datagram’s, such as dial-up, DSL, cable-modem, wireless or dedicated high speed interconnects.

ISPs may provide Internet e-mail accounts to users which allow them to communicate with one another by sending and receiving electronic messages through their ISP's servers. (As part of their e-mail service, ISPs usually offer the user an email clients software package, developed either internally or through an outside contract arrangement) ISPs may provideother services such as remotely storing data files on behalf of their customers, as well as other services unique to each particular ISP.

End-user-to-ISP connectionISPs employ a range of technologies to enable consumers to connect to their network.For users and small business, the most popular options include dial-up DSL , broadband wireless, cable modem, fibre to premises (FTTH), and integrated service digital network (ISDN).

When using a dial-up or ISDN connection method, the ISP cannot determine the caller's physical location to more detail than using the number transmitted using an appropriate form of Caller IDs; it is entirely possible to e.g. connect to an ISP located in Mexico from the USA. Other means of connection such as cable or DSL require a fixed registered connection node, usually associated at the ISP with a physical address ISP interconnection Just as their customers pay them for Internet access, ISPs themselves pay upstream ISPs for Internet access.

Peering

ISPs may engage in peering, where multiple ISPs interconnect at peering point or internet exchange point (IXs), allowing routing of data between each network, without charging one

another for the data transmitted data that would otherwise have passed through a third upstream ISP, incurring charges from the upstream ISP. ISPs requiring no upstream and having only customers (end customers and/or peer ISPs) are called Tier 1 ISPs.. Network hardware, software and specifications, as well as the expertise of network management personnel are important in ensuring that data follows the most efficient route, and upstream connections work reliably. A trade off between cost and efficiency is possible. A traditional fixed broadband network provides its services to a location/port. Multiple devices may connect to these services through the residential LAN and a common residential gateway. However, services are typically not individualized for these devices or the users using them. A mobile broadband network, on the other hand, typically deliver services to individual devices and users, providing them access to the subscribed services wherever they are. In a Full Service Broadband network, these two service paradigms are combined, providing users with services anywhere and from any device. Users can authenticate themselves and reach all their services from any device. A device can either connect through a mobile access or a fixed access, enabling a transparent experience, i.e. the same or very similar. Devices connected to the residential LAN are reachable also from devices on the move, enabling transparent access to e.g. stored media (figure below).

LAN

A local area network (LAN) is a Computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport. The defining characteristics of LANs, in contrast to wide area networks(WANs) include their usually higher data-transfer rates, smaller geographic area, and lack of a need for leased telecommunication lines. Current wired LANs are most likely to be based on Ethernettechnology, although new standards like ITU G also provide a way to create a wired LAN using existing home wires (coaxial cables, phone lines and power lines).

Campus area network

A Campus area network (CAN) is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area. It can be considered one form of a metropolitan area network, specific to an academic setting. In the case of a university campus-based campus area network, the network is likely to link a variety of campus buildings including; academic departments, the university library and student residence halls. A campus area network is larger than a local area network but smaller than a wide areanetwork (WAN) (in some cases).

Metropolitan area network

A metropolitan area network (MAN) is a network that connects two or more local area networks or campus area networks together but does not extend beyond the boundaries of the immediate town/city. Routers, switches and hubs are connected to create a metropolitan area network.

Wide area network

A wide area network (WAN) is a computer network that covers a broad area (i.e. any network whose communications links cross metropolitan, regional, or national boundaries . Less formally, a WAN is a network that uses routers and public communications links. Contrast with personal area networks (PANs), local area networks (LANs), campus area networks (CANs), or metropolitan area networks (MANs), which are usually limited to a room,building, campus or specific metropolitan area (e.g., a city) respectively.

Global area network

A global area networks (GAN) specification is in development by several groups, and there is no common definition. In general, however, a GAN is a model for supporting mobile communications across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is "handing off" the user communications from one local coverage area to the next.

Virtual private network

A virtual private network (VPN) is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) instead of by physical wires. The data link layer protocols of the virtual network are

said to be tunnelled through the larger network when this is the case. One common application is secure communications through the public Internet, but a VPN need nothave explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.

Hubs

A network hub contains multiple ports. When a packet arrives at one port, it is copied unmodified to all ports of the hub for transmission. The destination address in the frame is not changed to a broadcast address.

Bridges

A Network bridge connects multiple network segments at the data link layer (layer 2) of the OSI model. Bridges do not promiscuously copy traffic to all ports, as hubs do, but learn which MAC address are reachable through specific ports. Once the bridge associates a port and an address, it will send traffic for that address only to that port. Bridges do send broadcasts to all ports except the one on which the broadcast was received.

Internet

The Internet is a global system of interconnected computer network that use the standard Internet protocol (TCP/IP) to serve billions of users worldwide. It is a network of networks that consists of millions of private and public, academic, business, and government networks of local to global scope that are linked by a broad array of electronic and optical networkingtechnologies. The Internet carries a vast array of information resources and services, most notably the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support electronic mail. Most traditional communications media, such as telephone and television services, are reshaped or redefined using the technologies of the Internet, giving rise to services such as Voice over Internet protocol (VoIP) and IPTV.Newspaper publishing has been reshaped into Web sites, blogging , and web feeds. The Internet has enabled or accelerated the creation of new forms of human interactions through instant messaging, Internet forum , and social networking sites.

Terminology

The terms Internet and World Wide Web are often used in everyday speech without much distinction. However, the Internet and the World Wide Web are not one and the same. The Internet is a global data communications system. It is a hardware and software infrastructure that provides connectivity between computers. In contrast, the Web is one of the servicescommunicated via the Internet. It is a collection of interconnected documents and other resources , linked by hyperlinks and URLs. The term the Internet, when referring to the Internet, has traditionally been treated as a proper noun and written with an initial capital letter. There is a trend to regard it as a generic term or common noun and thus write it as "theinternet", without the capital.

Communication

E-MAIL is an important communications service available on the Internet. The concept of sending electronic text messages between parties in a way analogous to mailing letters or memos predates the creation of the Internet.Today it is important to distinguish between internet and internal e-mail systems. Internet e-mail may travel and be stored unencrypted on many other networks and machines out of both the sender's and the recipient's control. During this time it is quite possible for the content to be read and even tampered with by third parties, if anyone considers it important enough. purely internal or intranet mail systems, where the information never leaves the corporate or organization's network, are much more secure, although in any organization there will be IT and other personnel whose job may involve monitoring, and occasionally accessing, the e-mail of other employees not addressed to them. Pictures, documents and other files can be sent as email attachments . E-mails can be cc-ed to multiple-mail address.

Social impact

The Internet has enabled entirely new forms of social interaction, activities, and organizing, thanks to its basic features such as widespread usability and access. Social networking websites such as Facebook and MySpace, Orkut have created a new form of socialization and interaction. Users of these sites are able to add a wide variety of information to their personal pages, to persue common interests, and to connect with others. It is also possible to find a large circle of existing acquaintances, especially if a site allows users to represent themselves by their given names, and to allow communication among existing groups of people. Sites like meet-up.com exist to allow wider announcement of groups which may exist mainly for face-to-face meetings, but which may have a variety of minor interactions over their group's site. In India, leased lines are available at speeds of 64k, 128k, 256k