01-12-2012, 12:45 PM
PROJECT REPORT ON NETWORKING AND TELEPHONY
NETWORKING AND TELEPHONY.docx (Size: 888.3 KB / Downloads: 34)
ABSTRACT
The basis of this project was to learn NETWORKING & TELEPHONY SYSTEM, to understand “what is VOIP(voice over IP) and its working”. In this project we covered all the basics of networking , internet, networking model and all its protocols.
The main idea was to build an understanding about VOIP and its application, advantages and limitations.The tools used to understand and implement our theoretical knowledge practically was “BOSON NETSIM”.We also worked on live servers incorporated with VOS, monitored the calls, their routing over networks, protocols
Voice over Internet Protocol, a category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls by sending voice data in packets using IP rather than by traditional circuit transmissions of the PSTN. One advantage of VoIP is that the telephone calls over the Internet do not incur a surcharge beyond what the user is paying for Internet access, much in the same way that the user doesn't pay for sending individual e-mails over the Internet.
There are many Internet telephony applications available. Some, like CoolTalk and NetMeeting, come bundled with popular Web browsers. Others are stand-alone products. VoIP also is referred to as Internet telephony, IP telephony, or Voice over the Internet (VOI)
OM TELENTIA
OM Telentia is a pioneer and leader in providing end-to-end solutions and telecom services to Call Centers and BPO’s. They provide feature-rich, affordable communication solutions that offer flexibility, portability and ease-of-use. They provide integrated data and telecom solutions for the Business Process industry with a full range of products and services delivered over Private Leased Circuits or the Internet.
OM Telentia strengths lie in enabling new technologies for delivering high quality and cost effective long distance telecommunications for the industry. Efficient data and voice telecom services are mission critical for the Business Process and Call Centre industry and they are the pioneers. Their VoIP packages enable anyone to make and receive long-distance calls almost anywhere at the most competitive rates available.
NETWORKING
LAN(Local Area Network)
A local area network (LAN) is a group of computers and associated devices that share a common communications line or wireless link. Typically, connected devices share the resources of a single processor or server within a small geographic area (for example, within an office building). Usually, the server has applications and data storage that are shared in common by multiple computer users. A local area network may serve as few as two or three users (for example, in a home network) or as many as thousands of users (for example, in an FDDI network). Ethernet is by far the most commonly used LAN technology. A number of corporations use the Token Ring technology. FDDI is sometimes used as a backbone LAN interconnecting Ethernet or Token Ring LANs. Another LAN technology, ARCNET, once the most commonly installed LAN technology, is still used in the industrial automation industry.Typically, a suite of application programs can be kept on the LAN server. Users who need an application frequently can download it once and then run it from their local hard disk. Users can order printing and other services as needed through applications run on the LAN server. A user can share files with others at the LAN server; read and write access is maintained by a LAN administrator. A LAN server may also be used as a Web server if safeguards are taken to secure internal applications and data from outside access.In some situations, a wireless LAN may be preferable to a wired LAN because it is cheaper to install and maintain.
MAN(Metropolitan Area Network)
A metropolitan area network (MAN) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN). The term is applied to the interconnection of networks in a city into a single larger network (which may then also offer efficient connection to a wide area network). It is also used to mean the interconnection of several local area networks by bridging them with backbone lines. The latter usage is also sometimes referred to as a campus network.Examples of metropolitan area networks of various sizes can be found in the metropolitan areas of London, England; Lodz, Poland; and Geneva, Switzerland. Large universities also sometimes use the term to describe their networks. A recent trend is the installation of wireless MANs.
WAN(Wide Area Network)
A wide area network (WAN) is a geographically dispersed telecommunications network. The term distinguishes a broader telecommunication structure from a local area network (LAN). A wide area network may be privately owned or rented, but the term usually connotes the inclusion of public (shared user) networks. An intermediate form of network in terms of geography is a metropolitan area network (MAN).
IP Addresses
An IP address is an address used in order to uniquely identify a device on an IP network. The address is made up of 32 binary bits, which can be divisible into a network portion and host portion with the help of a subnet mask. The 32 binary bits are broken into four octets (1 octet = 8 bits). Each octet is converted to decimal and separated by a period (dot). For this reason, an IP address is said to be expressed in dotted decimal format (for example, 172.16.81.100). The value in each octet ranges from 0 to 255 decimal, or 00000000 - 11111111 binary.
CIDR
Classless Interdomain Routing (CIDR) was introduced to improve both address space utilization and routing scalability in the Internet. It was needed because of the rapid growth of the Internet and growth of the IP routing tables held in the Internet routers.
CIDR moves way from the traditional IP classes (Class A, Class B, Class C, and so on). In CIDR , an IP network is represented by a prefix, which is an IP address and some indication of the length of the mask. Length means the number of left-most contiguous mask bits that are set to one. So network 172.16.0.0 255.255.0.0 can be represented as 172.16.0.0/16. CIDR also depicts a more hierarchical Internet architecture, where each domain takes its IP addresses from a higher level. This allows for the summarization of the domains to be done at the higher level. For example, if an ISP owns network 172.16.0.0/16, then the ISP can offer 172.16.1.0/24, 172.16.2.0/24, and so on to customers. Yet, when advertising to other providers, the ISP only needs to advertise 172.16.0.0/16.
OSI MODEL
The Open Systems Interconnection (OSI) model is a reference tool for understanding data communications between any two networked systems. It divides the communications processes into seven layers. Each layer both performs specific functions to support the layers above it and offers services to the layers below it. The three lowest layers focus on passing traffic through the network to an end system. The top four layers come into play in the end system to complete the process.
The main benefits of the OSI model include the following:
• Helps users understand the big picture of networking
• Helps users understand how hardware and software elements function together
• Makes troubleshooting easier by separating networks into manageable pieces
• Defines terms that networking professionals can use to compare basic functional relationships on different networks
• Helps users understand new technologies as they are developed
• Aids in interpreting vendor explanations of product functionality
VoIP Architecture and Protocol Stack
Current implementation of VoIP has two types of architectures, which are based on H.323 and SIP frameworks, respectively. SIP, which is defined in RFC2543 of the MMUSIC working group of IETF, is an application-layer control signaling protocol for creating, modifying, and terminating sessions with one or more participants. the fundamental architectures of these two implementations are the same. They consist of three main logical components: terminal, signaling server and gateway. They di_er in specific definitions of voice coding, transport protocols, control signaling, gateway control, and call management. QoS requirements of VoIP include packet loss, delay, and delay jitter. The current H.323 and SIP frameworks support some kind of interfaces to QoS management (e.g., the one between H.323 and RSVP), they do not provide functional QoS management mechanisms. Consequently, products in the market now (e.g., Cisco s and Alcatel s VoIP systems) cannot provide QoS guarantees to VoIP applications. QoS management architecture of VoIP can be partitioned into two planes: data plane and control plane. Mechanisms in data plane include packet classification, shaping, policing, management, scheduling, loss recovery, and error concealment. They implement the actions the
network needs to take on user packets, in order to enforce class services. Mechanisms in control plane consist of resource provisioning, engineering, admission control, resource reservation and connection management etc.
Overview of Services Provided by SIP Servers
Multimedia conferencing on the Internet was well developed by the research and academic community by 1997. This has been reflected in the explosion of commercial ventures for Internet multimedia during the past decade. Work started at the same time to extend the Internet multimedia architecture for use in telephony. Because of the enormous complexity and richness of services on the PSTN, this work has taken much longer to develop, and only at the end of 2000 had it reached a critical mass where true reengineering of the telephone system for the Internet was well understood. In the history of science and technology, many new technologies have found applications that were not envisaged by their inventors. With this limitation in mind, the following sections will provide an overview of services that are supported by SIP servers, such as those used by public VoIP service providers and in enterprise PBX networks.
The prevalent business model of VoIP service providers in early 2006, however, is to not support any features that require going outside the walled garden. The assumption of practically all VoIP service providers is that all services are provided in-house. This may change, however, as Internet-wide VoIP will mature. Recent work has shown that all or most services performed by SIP proxy servers in the network can also be performed by server-less P2P SIP.