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Syllabus UNIT-1 : Introduction Concepts: Goals and Applications of Networks, Network structure and architecture, The OSI reference model, services, Network Topology Design - Delay Analysis, Back Bone Design, Local Access Network Design, Physi...

Syllabus UNIT-1 : Introduction Concepts: Goals and Applications of Networks, Network structure and architecture, The OSI reference model, services, Network Topology Design - Delay Analysis, Back Bone Design, Local Access Network Design, Physical Layer Transmission Media, Switching methods, ISDN, Terminal Handling. UNIT-2 : Medium Access sub layer: Medium Access sub layer - Channel Allocations, LANprotocols - ALOHA protocols - Overview of IEEE standards - FDDI. Data Link Layer - Elementary Data Link Protocols, Sliding Window protocols, Error Handling. UNIT-3 : Network Layer: Network Layer - Point - to Pont Networks, routing, Congestion control Internetworking TCP / IP, IP packet, IP address, IPv6. UNIT-4 : Transport Layer: Transport Layer - Design issues, connection management, session Layer-Design issues, remote procedure call. Presentation Layer-Design issues, Data compression techniques, cryptography - TCP - Window Management. UNIT-5 : Application Layer: Application Layer: File Transfer, Access and Management, Electronic mail, Virtual Terminals, Other application. Example Networks - Internet and Public Networks. www.knowledgegate.in  Video chapters Chapter-1 (Basics): What is Computer Networks, Goals, Application, Data Communication, Transmission Mode, Network Criteria, Connection Type, Topology, LAN, WAN, MAN, OSI Model, All Layer Duties, Transmission Media, Switching, ISDN. Chapter-2 (Data Link Layer): Random Access, ALOHA, Slotted ALOHA, CSMA, (CSMA/CD), (CSMA/CA), Sliding Window Protocol, Stop-and-Wait, Go-Back-N, Selective Repeat ARQ, Error Handling, Parity Check, Hamming Codes, CheckSum, CRC, Ethernet, Token Bus, Token Ring, FDDI, Manchester Encoding. Chapter-3 (Network Layer): Basics, IPv4 Header, IPv6 Header, ARP, RARP, ICMP, IGMP, IPv4 Addressing, Notations, Classful Addressing, Class A, Class B, Class C, Class D, Class E, Casting, Subnetting, Classless Addressing, Routing, Flooding, Intra-Domain Vs Inter-Domain, Distance Vector Routing, Two-Node Instability, Split Horizon, Link State Routing. Chapter-4 (Transport Layer): Basics, Port Number, Socket Addressing, TCP-Header, Three-way- Handshake, User Datagram Protocol, Data Compression, Cryptography, Symmetric Key, DES, Asymmetric Key, RSA Algorithm, Block-Transposition Cipher. Chapter-5 (Application Layer): E-Mail, SMTP, POP3/IMAP4, MIME, Web-Based Mail, FTP, WWW, Cookies, HTTP, DNS, Name Space, Telnet, ARPANET, X.25, SNMP, Voice over IP, RPC, www.knowledgegate.in Firewall, Repeater, Hub, Bridge, Switch, Router, Gateway.  What is Computer Networks A computer network is a telecommunications network, which allows autonomous digital devices(nodes) to exchange data between each other using either wired or wireless connections to share resources (h/w or s/w) interconnected by a single technology e.g. internet. www.knowledgegate.in  Goals of Computer Networks Facilitating Communication: Enabling swift and efficient communication between individuals and organizations. Supports video conferencing, emails, instant messaging, etc. Resource Sharing: Allows users to share hardware and software resources. Enables printer sharing, file sharing, etc. Data Storage and Access: Centralized storage systems that allow data access from any connected device. Helps in easy data backup and recovery. Cost Efficiency: Reduces costs by sharing resources and avoiding duplication of hardware and software. Reliability and Redundancy: Enhances reliability through alternate paths and redundant systems in case of failures. www.knowledgegate.in  Applications of Computer Networks Business and Commerce: E-commerce, online banking, stock trading, etc. Facilitates remote working and global collaboration. Education: E-learning platforms, virtual classrooms, online exams, etc. Facilitates research and knowledge sharing. Healthcare: Telemedicine, electronic health records, remote patient monitoring, etc. Government Services: E-governance, online public services, secure communication between government agencies, etc. Entertainment: Online gaming, streaming services, social media platforms, etc. Scientific Research: Facilitates data sharing and collaboration on research projects between institutions worldwide. Travel and Hospitality: www.knowledgegate.in Online ticket booking, hotel reservations, GPS and navigation services, etc.  Data communication Data communications are the exchange of data between to two devices via some transmission medium. www.knowledgegate.in Data communication system has five components 1. Message- information (data) to be communicated e.g. text, audio, video. 2. Sender- device how sends the message (computer, phone, camera etc.) 3. Receiver- device how receives the message (computer, phone, television etc.) 4. Transmission medium – is the physical path by which a message travels from sender to receiver. 5. Protocol – Which includes Syntax, Semantics, Timing, De facto, De jure. www.knowledgegate.in  Transmission Mode Data flow between two systems can be categorised into three types – www.knowledgegate.in  Simplex The communication is unidirectional as a one-way street, one device always, other can always receive. E.g. radio, mouse. The simplex mode can use the entire capacity of the channel to send data in one direction. www.knowledgegate.in  Half duplex Each station can both transmit and receive, but not at the same time. E.g. like a one lane road, walkie-talkie etc. When one device is sending, the other can only receive, and vice versa. In a half-duplex transmission, the entire capacity of a channel is taken over by whichever of the two devices is transmitting at the time. Walkie-talkies are both half-duplex systems. Walkie-talkies www.knowledgegate.in  Full duplex Both stations can transmit and receive at the same time. Actually, it is two half duplex connections. Telephone network is an example of full-duplex mode, when two people are communicating by a telephone line, both can talk and listen at the same time. The capacity of the channel, must be divided between the two directions. www.knowledgegate.in  Network criteria A network must be able to meet a certain number of criteria. The most important of these are. 1. Delivery & Accuracy- Must deliver the data to correct destination without any error. 2. Performance – Can be measured in many ways including transit time, response time, number of users, type of transmission medium, capabilities of connected hardware’s and efficiency of software. 3. Reliability – Is a measure of frequency of failure and the time taken to resolve from the failure. 4. Security – Includes protecting data from unauthorised access, protecting data from damage and development. www.knowledgegate.in  Types of connection Point to point - A point-to-point connection provides a dedicated link between two devices. Most point-to-point connections use an actual length of wire or cable to connect the two ends, but other options, such as microwave or satellite links, are also possible. www.knowledgegate.in  Multipoint - A multipoint (also called multidrop) connection is one in which more than two specific devices share a single link. www.knowledgegate.in  Physical topology Refers to the way in which a network is laid out physically. Topology of a network is the geometric representation of the relationship of all the links and linking devices to one another. www.knowledgegate.in  Mesh Topology In a mesh topology, every device has a dedicated point-to-point link to every other device. We need, n (n -1) /2, duplex-mode links, where n is number of nodes. www.knowledgegate.in  Advantages 1. No traffic problems 2. Robust 3. Privacy or security 4. Fault identification and fault isolation easy. Disadvantage 1. Installation and reconnection are difficult. 2. The sheer bulk of the wiring. 3. Expensive. www.knowledgegate.in  Star Topology In a star topology, each device has a dedicated point-to-point link only to a central controller, usually called a hub. The devices are not directly linked to one another. The controller acts as an exchange: If one device wants to send data to another, it sends the data to the controller, which then relays the data to the other connected device. www.knowledgegate.in Advantages 1. Less expensive than a mesh topology. 2. Easy to install and reconfigure and less costly. 3. It is robust. If one link fails, only that link is affected. 4. Easy fault identification and fault isolation. Disadvantage 1. Dependency of the whole topology on one single point, the hub. 2. Often more cabling is required in a star than in some other topologies. www.knowledgegate.in  Bus Topology A bus topology, is multipoint. One long cable acts as a backbone to link all the devices in a network. Nodes are connected to the bus cable by drop lines and taps. A drop line is a connection running between the device and the main cable. A tap is a connector that either splices into the main cable or punctures the sheathing of a cable to create a contact with the metallic core. www.knowledgegate.in Advantages 1. Ease of installation. 2. Uses less cabling than mesh or star topologies. Disadvantage 1. Difficult reconnection and fault isolation. 2. Difficult to add new devices to network. 3. A fault or break in the bus cable stops all transmission. www.knowledgegate.in  Ring Topology In a ring topology, each device has a dedicated point-to-point connection with only the two devices on either side of it. A signal is passed along the ring in one direction, from device to device, until it reaches its destination. Each device in the ring incorporates a repeater. When a device receives a signal intended for another device, its repeater regenerates the bits and passes them along. www.knowledgegate.in Advantages 1. A ring is relatively easy to install and reconfigure. 2. Fault isolation is simplified. Disadvantages 1. A break in the ring (such as a disabled station) can disable the entire network. www.knowledgegate.in  Local Area Network (LAN) : LAN is usually limited to a few kilometers of area. It may be privately owned and could be a network inside an office on one of the floor of a building or a LAN could be a network consisting of the computers in an entire building. Wide Area Network (WAN) : WAN is made of all the networks in a (geographically) large area. The network in the entire state of UP could be a WAN. Metropolitan Area Network (MAN) : MAN is of size between LAN and WAN. It is larger than LAN but smaller than WAN. It may comprise the entire network in a city like Mumbai. www.knowledgegate.in