Networking lecture1
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- The document discusses computer networks and networking concepts such as goals, applications, reference models, hardware, software, protocols, and switching techniques. - It covers topics like OSI and TCP/IP models, LAN, MAN and WAN network types and topologies, protocol hierarchies, connection-oriented and connectionless services, and circuit switching, message switching, and packet switching. - The document also discusses peer-to-peer and client-server network models, and different network topologies like bus, star, and ring.
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Networking lecture1
- 2. Subject : Computer Networks (IC-701) Unit 1 Computer Network, Goals and Applications, Reference models – OSI and TCP/IP. A Comparative study. Network hardware – LAN, MAN and WAN and topologies, Network Software –protocol hierarchies, design issues for the layers, Connection Oriented and connection less services, Switching Techniques – Circuit Switching, Message switching, Packet Switching.
- 3. Computer Network • A computer network is a group of computers that use a set of common communication protocols over digital interconnections for the purpose of sharing resources located on or provided by the network nodes. • A network consists of two or more computers connected together, and they can communicate and share resources (e.g. information) The System can be geographically located anywhere.
- 4. Network Goals • Allow activities on multiple computer systems to communicate with each other • Shared memory, files, or data • Message passing • Remote Procedure Call • Integrated applications — distributed across physical space • Create abstractions that make these (relatively) transparent
- 5. Computer Network Features • Communication speed • File sharing • Back up and Roll back is easy • Software and Hardware sharing • Security • Scalability • Reliability
- 6. Advantages • Sharing devices such as printers saves money. • Site (software) licenses are likely to be cheaper than buying several standalone licenses. • Files can easily be shared between users. • Network users can communicate by email and instant messenger.
- 7. Disadvantages • Purchasing the network cabling and file servers can be expensive. • Managing a large network is complicated, requires training and a network manager usually needs to be employed. • If the file server breaks down the files on the file server become inaccessible. Email might still work if it is on a separate server. The computers can still be used but are isolated. • Viruses can spread to other computers throughout a computer network. • There is a danger of hacking, particularly with wide area networks. Security procedures are needed to prevent such abuse, eg a firewall.
- 8. Types of Networks Depending on one’s perspective, we can classify networks in different ways • Based on transmission media: Wired (UTP, coaxial cables, fiber-optic cables) and Wireless • Based on network size: LAN and WAN (and MAN) • Based on management method: Peer-to-peer and Client/Server • Based on topology (connectivity): Bus, Star, Ring etc
- 9. Network Topology The network topology defines the way in which computers, printers, and other devices are connected. A network topology describes the layout of the wire and devices as well as the paths used by data transmissions.
- 10. 11 Peer-to-Peer Networks •Peer-to-peer network is also called workgroup •No hierarchy among computers all are equal •No administrator responsible for the network
- 11. 12 •Advantages of peer-to-peer networks: • Low cost • Simple to configure • User has full accessibility of the computer •Disadvantages of peer-to-peer networks: • May have duplication in resources • Difficult to uphold security policy • Difficult to handle uneven loading •Where peer-to-peer network is appropriate: • 10 or less users • No specialized services required • Security is not an issue • Only limited growth in the foreseeable future
- 12. 13 Clients and Servers 1. Network Clients (Workstation) Computers that request network resources or services 1. Network Servers Computers that manage and provide network resources and services to clients Usually have more processing power, memory and hard disk space than clients Run Network Operating System that can manage not only data, but also users, groups, security, and applications on the network Servers often have a more stringent requirement on its performance and reliability
- 13. 14 Advantages of client/server networks • Facilitate resource sharing – centrally administrate and control • Facilitate system backup and improve fault tolerance • Enhance security – only administrator can have access to Server • Support more users – difficult to achieve with peer-to-peer networks Disadvantages of client/server networks • High cost for Servers • Need expert to configure the network • Introduce a single point of failure to the system
- 14. P2P topology is where one device is directly connected with another device. In PTM , Data transmitted from the central base station is broadcasting to all the subscribers But data coming from a subscriber is only received by the base station. PTM topology is typically used in wireless LAN, and wireless WAN.
- 15. 16 Topology ― 3 basic types Physical, Logical and Hybrid Bus Topology(Daisy chain) Ring Topology Star Topology Hub
- 16. 17 Bus Topology & Ring Topology • Simple and low-cost • A single cable called a trunk (backbone, segment) • Only one computer can send messages at a time • Passive topology - computer only listen for, not regenerate data Both are not secure, not fault tolerant and difficult to trouble shoot. Star Topology • Each computer has a cable connected to a single point • More cabling, hence higher cost • All signals transmission through the hub; if down, entire network down • Depending on the intelligence of hub, two or more computers may send message at the same time.
- 17. 1. In star topology, the nodes are connected to the central hub or router. In ring topology, every node is connected to it’s left and right side nodes. 2. In star topology, only hub is failure point. In ring topology, every nodes are failure point. 3. The cost of star topology is high. The cost of ring topology is low. 4. In star topology, the information is travel from central hub or router to all the nodes. In ring topology, the information is travel from nodes to nodes in ring manner in one direction. 5. The cables are required in star topology more than the ring topology. The cables are required in ring topology less than the star topology. 6. There are n links in Star topology, if there are n nodes. There are also n links in ring topology, if there are n nodes present. 7. A new cable is added to the central hub to add a new node. Whereas to add a new node in ring topology, the connection must be broken.
- 19. Assignment • LAN, WAN, PAN, CAN, MAN, SAN, WLAN, BAN, NAN etc.
- 20. Applications of Networks • Resource Sharing • Hardware (computing resources, disks, printers) • Software (application software) • Information Sharing • Easy accessibility from anywhere (files, databases) • Search Capability (WWW) • Communication • Email • Message broadcast • Remote computing • Centralized Control • Distributed processing (GRID Computing) • Security is good - users cannot see other users' files unlike on stand-alone machines. • Data is easy to backup as all the data is stored on the file server.
- 23. *All People Seems to Need Data Processing
- 36. TCP/IP that is Transmission Control Protocol and Internet Protocol was developed by Department of Defense's Project Research Agency (ARPA, later DARPA) as a part of a research project of network interconnection to connect remote machines. The features that stood out during the research, which led to making the TCP/IP reference model were: Support for a flexible architecture. Adding more machines to a network was easy. The network was robust, and connections remained intact until the source and destination machines were functioning. The overall idea was to allow one application on one computer to talk to(send data packets) another application running on different computer, using multiple paths.
- 37. Network issues • Addressing • Routing • Name Resolution (By DNS) • Flow & Control • Interoperability
- 38. TCP/IP Reference Model is a four-layered suite of communication protocols. ... TCP stands for Transmission Control Protocol and IP stands for Internet Protocol. The four layers in the TCP/IP protocol suite are − Host-to- Network Layer −It is the lowest layer that is concerned with the physical transmission of data. The Link layer is sometimes referred to as the Network access layer. The Transport layer is sometimes called the Host-to-Host layer. data segments packets Frames bits
- 42. Q. Find the Network ID , Subnet Mask and Class for the given IP? Q. Convert Network ID/IP into Binary.
- 45. Convert into Binary : IP 192.168.37.200 27 26 25 24 23 22 21 20 128 64 32 16 8 4 2 1 1 1 0 0 0 0 0 0 192 1 0 1 0 1 0 0 0 168 0 0 1 0 0 1 0 1 37 1 1 0 0 1 0 0 0 200 200 128+64+8 192 putting ‘1’ for 128 and 64 rest ‘0’ 168 putting ‘1’ for 128 +32 +8 37 32+4+1 As Shown above, we can take ‘1’ for the numbers whose sum is 192 i.e 128+64, similarly for 168 128+32+8 so on .. Therefore binary form is: 11000000.10101001.00100101.10010001
- 48. To find Network ID, usable host and broadcast ID? e.g. 1) 160.10.20.30 Network ID : 160.10.0.0 Broadcast ID: 160.10.255.255 In class B 2) 17.210.201.210 Network ID : 17.0.0.0 Broadcast ID: 17.255.255.255 Usable ID : . 28*3 -2 = 224 -1 in Class A As the number of usable host in this (Class B) IP is 8bits + 8 bits = 16 therefore its 216 (Total IPs) minus 2. 216 – 2 = 65534 usable IPs can be given to computer. As 1st (network IP) and last (Broadcast)one is Reserved.
- 49. Assignment 1. • Make ppt of : Router, Switch, Hub, Repeater, Gateway, Connectors, Cables types. Write 3 sentences on each. • Take any three IP address of Each Class A, B and C : 1. convert it into binary 2. Find the network ID 3. Find the usable ID
- 50. Switching Techniques • In large networks, there can be multiple paths from sender to receiver. The switching technique will decide the best route for data transmission. • Switching technique is used to connect the systems for making one-to-one communication.