A layered network model the osi reference model is composed of seven layers, each specifying particular network functions. This post present, data communication and networking notes on osi model in details. Pdf the internet protocols have become the worldwide standard for network and. Osi model data communication and networking notes in pdf. The main aim of this layer is to deliver packets from source to destination across multiple links networks.
Ethernet ethernet is a widely deployed lan technology. Ip addresses are 32 bit long, hierarchical addressing scheme. Sep 07, 2011 the network layer is considered the backbone of the osi model. A datalink protocol specifies the structure of the frame, as well as a channel access protocol that specifies the rules by which a frame is transmitted onto the link. The most significant protocol at layer 3 also called the network layer is the internet protocol, or ip. Introduction a computer network is the infrastructure that allows two or more computers called hosts to communicate with each other. Notice that the bottom layer is identified as the first layer. Network layer and ip protocol cse 32, winter 2010 instructor.
If two systems are attached to different networks with devices like routers, then nw layer is used. It selects and manages the best logical path for data transfer between nodes. Download network layer in osi model in pdf click here. The network layer is concerned with knowing the address of the neighboring nodes in the network, selecting routes and quality of service, and recognizing and forwarding to the transport layer incoming messages. Layer 3 network layer overview next we move on to the network layer, layer 3 of the osi model which controls broadcast domains. An ip address is 32 bits in length, divided into either two or three parts. Network locator topological point of attachment for routing purposes. Network layer it is responsible for the source to destination delivery of a packet across multiple networks. Networking mcq computer questions answers pdf download. Network layer manages options pertaining to host and network addressing, managing subnetworks, and internetworking. While the data link layer functions mostly inside wide area network wan and local area network lan, network layer handles the responsibility of the transmission of data in different networks. Each device attached to the network has a corresponding stack of these layers, where each layer conceptually talks to the corresponding layer on the other computer. This layer contains hardware devices such as routers, bridges, firewalls and switches, but it actually creates a logical image of the most efficient communication route and implements it with a physical medium.
Module 4 discuss how broadcast are performed, the devices that work at the network layer, then we explain in details what happens to the data that facilitates its transmission over the network. The application layer acts as interface between the applications and the underlying network. Tech 3rd year study material, lecture notes, books. The optical layer provides reconfigurable lightpaths that serve as. Each layer provides a service to the layer above it in the protocol specification. Data communication and computer network 8 let us go through various lan technologies in brief. It is an encapsulating protocol similar to the way ethernet is an encapsulating protocol. Osi model layers in computer networks pdf by ramandeep singh page 2 1. Ip is the standard for routing packets across interconnected networkshence, the name internet. If we view the original check as a unit of data needed to be sent, we now have two envelopes required. Ip is a standard that defines the manner in which the network layers of two hosts interact. Multiple choice questions of computer networking 11 computer network is a. Network layer takes the responsibility for routing packets from source to destination within or outside a subnet. A local area network data link layer and physical layer specifications.
Tanenbaum takes a structured approach to explaining how networks work from the inside out. The transport layer should be shielded from the number, type and topology of the subnets present. Computer networks pdf notes free download cn notes. Presentation application session transport network data link physical layer 7 layer 6 layer 5 layer 4 layer 3 layer 2 layer. Network layer 416 application transport network data link physical application transport network data link physical 1. Thus dll overseas the delivery of the packet between. Two different subnet may have different addressing schemes or non. Hope this will help you to understand the concept in a well manner. Professional ethics and human values pdf notes download b.
Prepare the physical devices enabling devices for transmission of data and data is received. Database management system pdf free download ebook b. The network addresses available to the transport layer should use a uniform numbering plan even across lans and wans. This is the seven layer or level in a complete communication system. The ethernet a local area network, data link layer and. It routes the signal through different channels to the other end and acts as a. Osi model 7 layers explained pdf layers functionsthe open systems interconnection model osi model is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology its goal is the interoperability of diverse communication systems with standard protocols.
Almost all linklayer protocols encapsulate each networklayer datagram within a networklayer datagram is inserted, and a number of header fields. The network layer is considered the backbone of the osi model. Data link layer it is responsible for nodetonode delivery of data. For example, assume that a network has been assigned a class b address, and all the nodes on the network currently conform to a class b address format. Layer 3 refers to the network layer of the commonlyreferenced multilayered communication model, open systems interconnection osi. The third layer of the open systems interconnection osi is called the network layer. Osi model layers in computer networks pdf by ramandeep singh page 1 osi osi stands for open system interconnection modelosi model. Layer 3 the network layer layer 3, the network layer of the osi model, provides an endtoend logical addressing system so that a packet of data can be routed across several layer 2 networks ethernet,token ring, frame relay, etc. Guide to ip layer network administration with linux version 0. Exam paper of computer networks i may 20 exam paper of dec 2011 and its solution exam paper of april 2012 and its solution exam october 2015, questions and answers computer networks 1 introduction computer networks i application layer lecture notes.
The services provided by the network layer should be independent of the subnet topology. Typically, the network layer adds its own header e. The network achieves this by providing a set of rules for communication, called protocols, which should be observed by all participating hosts. Chapter 1 introduction to networking and the osi model. After reading the summary below, use the download form above to get the pdf of chapter 1.
Describe the functionality of lan, man, and wan networks. As with all network layer protocols, the addressing scheme is integral to the process of routing ip datagrams through an internetwork. Host identifier unique for a host and tcpip stack 5. Internet router architecture 8 router 3 layer physical, datalink, network device, with 3 key functions. Osi model 7 layers explained pdf layers functionsthe open systems interconnection model osi model is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. If two computers system are connected on the same link, then there is no need for a network layer. A network is a set of devices often referred to as nodes connected by communication links. Tech 3rd year lecture notes, study materials, books.
Note that network layer addresses can also be referred to as logical addresses. Computer network layers cis748 class notes alex s 1 the layers normally, the task of communication from computer to computer is broken up into layers. Pdf resource management and network layer researchgate. Defines the methods and provides addressing information for communication between network devices. The network layer controls the operation of the subnet. Type of connection a network is two or more devices connected through links. This address is technically called the media access control address mac because it is found on the mac sub layer of the data link layer. Guide to ip layer network administration with linux. Internet router architecture 8 router 3layer physical, datalink, network device, with 3 key functions. He starts with an explanation of the physical layer of networking, computer hardware and transmission systems. This will provide you with an overview of the network process, which can then act as a framework for understanding the details of computer networking. The network interface card address, called the hardware address, is protocolindependent and is usually assigned at the factory.
It use to transfer data over a network which moves through different layer. Physical layer 47 data link layer 48 network layer 49 transport layer 51 session layer 53 presentation layer 54 application layer 55 summary of layer functions 56 3. Igmp used by host and routers to achieve efficient network layer. The ethernet specification is the result of an extensive collaborative effort of the three corporations, and several years of work at xerox on an earlier prototype ethernet.
Application layer protocols help exchange data between programs running on the source and destination hosts. Almost all link layer protocols encapsulate each network layer datagram within a network layer datagram is inserted, and a number of header fields. Layer valley from simi valley to silicon valley how to 7 layer dip physical layer smear layer boundary layer absite layer layer application speed eos 290 mobile network layer network layer security tranport layer chapter boundary layer theory service bus abstraction layer automation pyramid and identify layer schlichting, h. All of the above 12 what is a firewall in computer.
Core network bts bsc gprs access bts bsc gsm network 2g ggsn sgsn cn internet ip mobility and cellular networks mail. It is responsible for establish and termination of connection between two nodes over a network. This technology was invented by bob metcalfe and d. Network applications enable users to send and receive data with ease. Network layer responsibility direct communication model. A network can be defined as a group of computers and other devices.
A network must provide connectivity among a set of computers. Internet protocol from book the data communications and networking 4th edition by behrouz a. All of the above 12 what is a firewall in computer network. The process of breaking up the functions or tasks of networking into layers reduces complexity. Osi model 7 layers explained pdf layers functions the open systems interconnection model osi model is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology its goal is the interoperability of diverse communication systems with standard protocols. Network security issues include protecting data from unauthorized access, protecting data from damage and development, and implementing policies and procedures for recovery from breaches and data losses. The first part designates the network address, the second part if present designates the subnet. Network which uses shared media has high probability of. Receive data forwarding table destination address range link interface 1100 00010111 0000 00000000 through 0 1100 00010111 00010111 11111111 4 billion. A node can be a computer, printer, or any other device capable of sending andor receiving data generated by other nodes on the network. This document contains the specification of the ethernet, a local area network developed jointly by digital equipment corporation, intel corporation, and xerox corporation. Understand principles behind network layer services. The network layer takes the segment, and appends the source and destination ip. Guide to ip layer network administration with linux vii 3.