The network layertransport layer interface frequently is the interface between the carrier and the customer, that is the boundary of the subnet. If two systems are attached to different networks with devices like routers, then nw layer is used. Network layer supervises hosttohost packet delivery hosts could be separated by several physical networks. Starting from the physical layer, progressing to the data link layer ethernet, and moving up through the network layer ip and routing on to the transport layer tcp and udp, there are a large number of terms to be understood. It is an encapsulating protocol similar to the way ethernet is an encapsulating protocol. The network layer is considered the backbone of the osi model.
Ospf, bgp, openflow, odl and onos controllers, icmp, snmp. Theyre in powerpoint form so you can add, modify, and delete slides including this one and slide content to suit your needs. The nic is effectively a method of connecting the internal data bus of a computer to the external media cables of the network. An ip address is layer 3 network layer logical address. Network layer computer networks questions and answers.
Routing algorithm network layer linkedin slideshare. Network layer and ip protocol cse 32, winter 2010 instructor. The network layer protocols determine which route is suitable from source to destination. Network layer protocol tutorial to learn network layer protocol in simple, easy and step by step way with syntax, examples and notes. Forwarding when a packet arrives at a routers input link, the router must move the packet to the appropriate output link. Internet protocol multiple choice questions and answers mcq pdf covers the below lists of topics. Routing the process of transferring packets received from the data link layer of the source network to the data link layer of the correct destination network is. This function of network layer is known as routing. It is important to remember the order of the layers in the osi model. Describe the function and operation of layer 2 switching.
In order to deliver the message from one process to another, an addressing scheme is required. 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. The network interface card address, called the hardware address, is protocolindependent and is usually assigned at the factory. Network layer internet protocol multiple choice questions. Several process may be running on a system at a time. This paper describes an architecture for adding an underlying wavelengthrouted optical layer to a standard atm network. The network layer translates the logical addresses into physical addresses. All of the above 12 what is a firewall in computer network. The network layer provides the means of transferring variablelength network packets from a source to a destination host via one or more networks. Ip is a standard that defines the manner in which the network layers of two hosts interact. Layer 3 refers to the network layer of the commonlyreferenced multilayered communication model, open systems interconnection osi. Were making these slides freely available to all faculty, students, readers. The network layer services have been designed with the following goals in mind.
In the sevenlayer osi model, the network layer is layer 3 which defines communication between the different networks and most commonly known as the layer where routing takes place. Network layer design issues storeandforward packet switching services provided to the transport layer implementation of connectionless service implementation of connectionoriented service comparison of virtualcircuit and datagram networks 4. Guide to ip layer network administration with linux vii 3. Guide to ip layer network administration with linux. Transport layer does not perform any function in the intermediate nodes. The transport layer should be shielded from the number, type, and topology of the routers present. Ip is the standard for routing packets across interconnected networkshence, the name internet. The network addresses made available to the transport layer should use a uniform numbering. This is the networking questions and answers section on network layer with explanation for various interview, competitive examination and entrance test. This address may change every time a computer restarts. Defines the methods and provides addressing information for communication between network devices. In order to identify each device on internetwork uniquely, network layer defines an addressing scheme. Network layer, or osi layer 3, provides services to exchange the individual pieces of data over the network between identified end devices. Physical media, layer 1 the physical network also called the physical layer begins at the network interface card nic.
It determines the route from the source to the destination and also manages the traffic. Presentation application session transport network data link physical layer 7 layer 6 layer 5 layer 4 layer 3 layer 2 layer. Network layer protocol an overview sciencedirect topics. Whether the network layer provides datagram service or virtual circuit service, the main job of the network layer is to provide the best route. It is responsible for message delivery from process running in source computer to the process running in the destination computer. The network addresses available to the transport layer should use a uniform numbering plan even across lans and wans. At the network layer, the data is in the form of packets or also called as datagram. Presentation application session transport network data link physical layer 7 layer 6 layer 5 layer 4 layer 3 layer 2 layer 1. The first step in discussing network technology is to ensure that you understand the terms and acronyms. If two computers system are connected on the same link, then there is no need for a network layer. In order to identify the correct process out of the various running processes, transport layer uses an addressing scheme called por number. Outline routing algorithm shortest path routing flow based routing flooding distance vector routing link state routing. Common network layer protocols internet protocol version 4 ipv4 internet protocol version 6 ipv6 legacy network layer protocols novell internetwork packet exchange ipx appletalk connectionless network service clnsdecnet 6. The services provided by the network layer should be independent of the subnet topology.
It is important to note that a single end system may have multiple network interfaces. The network layer is the third layer of the osi model. The network layer controls the operation of the subnet. Multiple choice questions of computer networking 11 computer network is a. It handles the service requests from the transport layer and further forwards the service request to the data link layer.
The main aim of this layer is to deliver packets from source to destination across multiple links networks. Network layer the network layer module accepts incoming packets from the transport layer and transit packets from the dlc layer it routes each packet to the proper outgoing dlc or at the destination to the transport layer typically, the network layer adds its own header to the packets received from the transport layer. The internet protocols primary function is logical network layer addressing of. The process of breaking up the functions or tasks of networking into layers reduces complexity. To accomplish this endtoend transport, layer 3 uses four basic processes. Sambhe assistant professor, department of computer technology, yeshwantrao chavan college of engineering, nagpur 1.
Chapter 1 introduction to networking and the osi model. Network layer protocol configuration phase after the link is established and lcp negotiates optional facilities as needed, ppp must send ncp packets to choose and configure one or more network layer protocols. The network layer is the third level of the open systems interconnection model osi model and the layer that provides data routing paths for network communication. Two types of packets are used at the network layer. Data packets data packets are used to transport the user data across the network. Covers topics like introduction to network layer, functions of network layer, ipv4, datagrams, fragmentation, maximum transfer unit, shortfalls of ipv4 etc. When source and destination are in different networks, the.
To do so, two important networklayer functions can be identified. Doing so creates a better understanding of the network data flow. A top down approach 6th edition if you use these slides e. Ip addresses are 32 bit long, hierarchical addressing scheme. Computer networks pdf notes free download cn notes. If we view the original check as a unit of data needed to be sent, we now have two envelopes. 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. Every computer in a network has an ip address by which it can be uniquely identified and addressed. The network layer must know the topology of the subnet and choose appropriate paths through it. A layered network model the osi reference model is composed of seven layers, each specifying particular network functions. Notice that the bottom layer is identified as the first layer. Internetwork layer application transport internetwork link physical 7 4 3 2 1 bridges multiple subnets to provide endtoend internet connectivity between nodes provides global addressing ip addresses only provides besteffort delivery of data i.
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. Sambhe assistant professor, department of computer technology, yeshwantrao chavan college of engineering, nagpur 1 2. Network layer it is responsible for the source to destination delivery of a packet across multiple networks. Data networks lecture 1 introduction mit opencourseware. Two different subnet may have different addressing schemes or non. Note that network layer addresses can also be referred to as logical addresses. The services should be independent of the router technology. Network layer introduction, functions and protocols. In network layer protocols, specifically in the ip, addresses identify network adapters. The routing protocol is a routing algorithm that provides the best path from the source to the destination. Dec 14, 2015 network layer is the lowest layer that deals with endtoend transmission.
Data link layer it is responsible for nodetonode delivery of data. The thirdlowest layer of the osi reference model is the network layer. Data is transferred in the form of packets via logical network paths in an ordered format controlled by the network layer. It routes the signal through different channels to the other end and acts as a. Note that net work layer addresses can also be referred to as logical addresses. Vc network provides network layer connection service analogous to the transport layer services, but. It selects and manages the best logical path for data transfer between nodes. This data communication and networking network layer. Network layer manages options pertaining to host and network addressing, managing subnetworks, and internetworking. Application, transport, network and link layers last modified.
Within the service layering semantics of the osi network architecture, the network layer responds to service requests from the transport layer and issues service requests to the data link layer. Forwarding and routing in network layer the role of the network layer is thus deceptively simple to move packets from a sending host to a receiving host. Network layer is the lowest layer that deals with endtoend transmission. Dimitrios serpanos, tilman wolf, in architecture of network systems, 2011. Understand principles behind network layer services. Forwarding and routing in network layer electronics post. The most significant protocol at layer 3 also called the network layer is the internet protocol, or ip. A computer can have one ip at one instance of time and another ip at some different time. The transport layer is the fourth layer from the bottom in the osi reference model.
All the multiple choice question and answer mcqs have been compiled from the books of data communication and networking by the well known author behrouz a forouzan. 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. Network layer takes the responsibility for routing packets from source to destination within or outside a subnet. Data link layer, layer 2 in the tcpipbased layered network, layer 2 is the data link layer. Thus dll overseas the delivery of the packet between the two systems on same network and the network. This paper describes an architecture for adding an underlying wavelengthrouted optical layer. For example, a typical laptop today has one network interface that uses wired ethernet, one network interface that. 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. If the data link layer is the one that basically defines the boundaries of what is considered a network, the network layer is the one that defines how internetworks interconnected networks function.
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