The network layer is concerned with getting packets from the source all the way to the destination with minimal cost. Unlike the data link layer which has more important goals like just moving frames from one end of a wire to another. The network layer is the lowest layer that deals with end-to-end transmission.Network Layer Design issuesNetwork layer Design issues are as follows −Store and forward packets switchingServices provided to the transport layerImplementation of connectionless servicesImplementation of connection oriented servicesComparison of virtual-circuit datagram networksNow let us see one of the design issues of the network layer.Services provided to the transport ... Read More

Data link layer translates the physical layers raw bit stream into discrete messages called frames. Now the question is how can a frame be transmitted, so the receiver can recognize the start and end frame?TechniquesThe techniques we used to find the start and end frame are −Character countFlag byte with byte stuffingStarting and ending flag with bit stuffingEncoding Violation.Now let us see the Physical layer encoding violation technique.Physical layer encoding violationThis framing method is used only in those networks in which encoding on the physical medium contain some redundancy.Some LANs encode each bit of data by using two physical bits ... Read More

Data link layer translates the physical layers raw bit stream into discrete messages called frames. Now the question is how can a frame be transmitted, so the receiver can recognize the start and end frame?TechniquesThe techniques we used to find the start and end frame are −Character countFlag byte with byte stuffingStarting and ending flag with bit stuffingEncoding Violation.Now let us see the character count technique.Character CountFirst framing method uses a field in the header to specify the number of characters in the frame. When the data link layer at the destination sees the character count, it knows how many ... Read More

Elementary Data Link protocols are classified into three categories, as given below −Protocol 1 − Unrestricted simplex protocolProtocol 2 − Simplex stop and wait protocolProtocol 3 − Simplex protocol for noisy channels.Let us discuss each protocol one by one.Unrestricted Simplex ProtocolData transmitting is carried out in one direction only. The transmission (Tx) and receiving (Rx) are always ready and the processing time can be ignored. In this protocol, infinite buffer space is available, and no errors are occurring that is no damage frames and no lost frames.The Unrestricted Simplex Protocol is diagrammatically represented as follows −Simplex Stop and Wait protocolIn ... Read More

The Data Link layer is located between physical and network layers. It provides services to the Network layer and it receives services from the physical layer. The scope of the data link layer is node-to-node.The following are the design issues in the Data Link Layer −The services that are provided to the Network layer.FramingError controlFlow controlServices to the Network LayerIn OSI each layer uses the services of the bottom layer and provides services to the above layer. The main function of this layer is to provide a well defined service interface over the network layer.Types of ServicesThe services are of ... Read More

Digital Modulation is the process of converting between bits and signals.Transmission MechanismsThe various modulation schemes result in various transmission mechanisms which are as follows −Baseband transmission.Passband transmission.Multiplexing TechniquesSharing of a transmission channel by various signals is called multiplexing. The different multiplexing techniques are as follows −Time division multiplexing.Frequency division multiplexing.Code division multiplexing.Now, let us discuss one of the digital modulation schemes.Passband TransmissionPassband transmission is the transmission after shifting the baseband frequencies to some higher frequency range using modulation. It is used for long distances.Steps for Passband TransmissionLet us understand the Passband transmission step by step.Step 1 − Generally, we want ... Read More

Digital Modulation is the process of converting between bits and signals.Transmission MechanismsThe various modulation schemes result in various transmission mechanisms which are as follows −Baseband transmission.Passband transmission.Multiplexing TechniquesSharing of a transmission channel by various signals is called multiplexing. The different multiplexing techniques are as follows −Time division multiplexing.Frequency division multiplexing.Code division multiplexing.Now, let us discuss one of the digital modulation schemes.Baseband TransmissionBaseband transmission is transmission of the encoded signal using its own baseband frequencies i.e. without any shift to higher frequency ranges. It is used for short distances.Steps in Baseband TransmissionLet us understand the baseband transmission step by step.Step 1 ... Read More

Digital wireless communication is not a new idea. Earlier, Morse code implemented the wireless network. Now-a-days, the modern digital systems use wireless systems of the same idea as Morse code as implemented but with better performance.Categories of Wireless NetworksWireless Networks are divided into three categories as explained below −System InterconnectionIt is all about interconnecting the components of a computer using short-range radio. Some companies together design a short-range wireless network called Bluetooth to connect various components like monitor, keyboard, mouse, printer etc, without wires.In simplest form, system interconnection networks use the master-slave concept. The system unit is normally the master. ... Read More

Topology refers to the arrangement of computer networks. Topology is divided into either physical or logical arrangement. Physical topology refers to the way the computers are connected with each other on a network. Logical topology means the way data is flowing from one computer to another computer.Now, let see the basic definition of computer network topology, it is the schematic description of network arrangements that are connected through various nodes with the help of lines of connection.Types of Network TopologyThe different types of network topology are as follows −Bus topologyRing topologySTAR topologyMESH topologyTREE topologyHybrid TopologyLet us understand the concept of ... Read More

Transmitting the data in the form of packets over the internet is called casting.Types of CastingsThe different types of casting are as follows −Unicast − Transmitting data from one host to another host (one-one)Broad cast − Transmitting data from one host to many host (one-all)Multicast − Transmitting data from one host to a particular group of host (one-many).Let us see each casting type in detail −UnicastTransmitting data from one source host to one destination host is called a unicast. It is called as a one to one transmission.For example − source Host IP Address 192.168.20.1 sending data to destination Host ... Read More