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Computer networking (nnm)

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The document provides an overview of computer networking, including definitions of key terms like computer network and network topology. It discusses why networks are needed, how they work, common network models like OSI and TCP/IP. It also covers topics like IP addressing, different network types (LAN, MAN, WAN), common network devices, applications, and security concerns.

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COMPUTER NETWORKING N. N. Maurya
NETWORKING OF COMPUTERS  What is computer network?  Why we need a computer network ?  How a computer network works ?  Network models  IP Addressing  Network Topology  Different type of network  Requirements for network  Applications  Security
WHAT IS NETWORK ?  Interconnection of computers  How to interconnect ?  Links required for interconnecting „N‟ nodes  Suitable ?  Solution ?
GOALS OF THE NETWORKING  Resource Sharing  Information/Data Sharing  Centralized Computing  Remote Computing  Communication – Mail, Video Conferencing  Improving Security  Managing Tasks and Applications
THE PAST
THE PRESENT : CONVERGENCE
THE FUTURE : INTERNET AS PLATFORM
SOME BASICS  Why a computer network is required ?  Data transfer  How to identify a node in network ?  IP address  How data flows in networks ?  Packet form  What is Packet switching ?  Statistical Multiplexing ReceiverSender Packet Transmission
SOME BASICS……..  Channel capacity = Maximum data rate for a channel  Nyquist Theorem:  Bandwidth = W  Data rate =< 2W  Bilevel encoding:  Data rate = 2 X Bandwidth  Multilevel encoding:  Data rate = 2 X Bandwidth X log 2 M  For example if M = 4, Capacity = 4 X Bandwidth  Shannon‟s Theorem:  Maximum number of bits/sec = W log2 (1+S/N)  For telephone line: S/N = 30 dB, W = 3K; Capacity = 30Kbps
TREND: TRAFFIC > CAPACITY Expensive Bandwidth Cheap Bandwidth Sharing No sharing Multicast Unicast Needs QoS QoS is not an issue Wireless LAN Possible in LAN
NETWORK MODELS  Network models  OSI  TCP/IP  Connection oriented protocol  Connectionless protocol
OSI REFERENCE MODEL  The seven layers  Each layer hides complexity of lower layer  Layering enforces modularity
 End-to-end layer: top 4 OSI layers  Network layer: OSI network layer  Link layer: bottom 2 OSI layers  A-P-S-T are implemented in software  N-D-P are implemented in hardware THE SEVEN LAYERS
THE SEVEN LAYERS ………….  Physical layer  Transmission of bit stream over physical medium  Coding scheme, connector shape and size, bit-level synchronization  Data link layer  Reliable transfer of information across the physical link  Sends blocks - frames  Medium access control (MAC): data link-layer address and access to the medium  Logical link control: link error control and flow control  Ethernet card: physical and data link layers
THE SEVEN LAYERS ………….  Network layer  Concatenate logically a set of links to form an end-to- end link.  Compute a route  Segmentation and reassembly  Unique network-wide addresses : IP address  The beauty of IP is that we can layer it over any data link layer technology  Type-of-service in the IP
THE SEVEN LAYERS ………….  Transport layer  Create the abstraction of an error-controlled, and flow-controlled, end-to-end link  Multiplex multiple applications to the same end-to-end connection  Port number
THE SEVEN LAYERS ………….  Best-effort network layer - drops packets - delays packets - reorders packets - corrupts packet contents  Many applications want reliable transport - all packets reach receiver… …in order they were sent - no data corrupted - “reliable byte stream”  Need a transport protocol, e.g., Internet‟s Transmission Control Protocol (TCP)
PRINCIPLES OF RELIABLE DATA TRANSFER  Important in application, transport, and link layers  Top-10 list of important networking topics! Sending Process Receiving Process Reliable Channel Sending Process Receiving Process Unreliable Channel RDT protocol (sending side) RDT protocol (receiving side) Application Layer Network Layer Transport Layer  Characteristics of unreliable channel will determine complexity of reliable data transfer protocol
THE SEVEN LAYERS ………….  Session layer  provides the control structure for communication between applications  The Internet does not have a standard session layer protocol.  Presentation layer  deals with data  encrypt data  The Internet does not support a standard presentation layer.  Application layer  Provides access to the users  WWW: browser, server, navigation  file transfer using TCP  real-time audio and video retrieval using UDP
TCP/IP MODEL  TCP/IP protocol consists of four/five layers  The lower layers correspond to the layer of the OSI model.  The application layer of the TCP/IP model represents the three topmost layers of the OSI model  TCP/IP is based on two principles  IP Over everything  end to end
TCP/IP MODEL………..  TCP – Transmission Control Protocol  IP – Internet Protocol (Routing) TCP/IP Model TCP/IP Protocols OSI Ref Model Physical Datalink Network Transport Session Presentation Application Physical Datalink Network Transport Session Presentation Application Host to Network Network Transport Application Host to Network Network Transport Application UDP HTTPTelnet Point - to - Point Packet Radio Ethernet IP TCP FTP UDP HTTPTelnet Point - to - Point Packet Radio Ethernet IP TCP FTP
ADVANTAGE OF TCP/IP MODEL  Open Protocol Standards  Independent of actual physical network & Computer hardware or software. Run over Ethernet/ Token Ring/ Modems/ Unix/ Windows PCs  Uses Common Global address scheme (IP addressing) that enables global connectivity
IP ADDRESSING  IP addressing scheme is integral to the process of routing IP datagram through an internetwork.  Each IP address has specific component and follows a basic format.  These IP addresses can be subdivided and used to create addresses for sub networks.  Each host on a TCP/IP network is assigned a unique 32-bit logical address that is divided into two main parts: the network number and the host number.  The network number identifies a network and must be assigned by the internet Network Information Center (InterNIC) if the network is to be part of the internet.
IP ADDRESSING  An Internet Service Provider (ISP) can obtain blocks of network addresses from InterNIC and can itself assign address space as necessary.  The host number identifies a host on a network and is assigned by the local network administrator.
IP ADDRESSING  Class D and E are reserved for multicasting and research
IP ADDRESSING - SUBNETTING
IP CONFIGURATION Static DHCP
COMPONENTS OF A NETWORK  Server :Computer that provides shared resources to network users.  Clients :Computer that access shared network resources provided by server.  Media : Way of connecting computers. e.g. Cable, fiber optics, telephone line.  Resources: Files, printers or other items to be used by network users.
NETWORK ARCHITECTURES  Client-server  Peer-to-peer (P2P)  Hybrid of client-server and P2P
CLIENT-SERVER ARCHITECTURE server:  always-on host  permanent IP address clients:  communicate with server  may be intermittently connected  may have dynamic IP addresses  do not communicate directly with each other client/server
P2P ARCHITECTURE  no always-on server  users directly communicate  peers are intermittently connected and change IP addresses Highly scalable but difficult to manage peer-peer
HYBRID OF CLIENT-SERVER AND P2P Skype  voice-over-IP P2P application  centralized server: finding address of remote party  client-client connection: direct (not through server) Instant messaging  chatting between two users is P2P  centralized service: client presence detection  user registers its IP address with central server when it comes online  user contacts central server to find IP addresses of buddies
NETWORK TOPOLOGY  Defines the way in which computers, printers, and other devices are connected.  Describes the layout of the wire and devices as well as the paths used by data transmissions.
BUS TOPOLOGY  All the devices on a bus topology are connected by one single cable  At a time only one host can send messages  Passive topology. Hosts on the bus are not responsible for moving data  Failure of any host doesn‟t affect the Network
STAR & TREE TOPOLOGY  Commonly used architecture in Ethernet LAN  Larger networks use the extended star topology also called tree topology
RING TOPOLOGY
FILE TRANSFER OVER NETWORK
FILE TRANSFER OVER NETWORK
CORPORATE INTERNET
IEEE 802 STANDARDS  802.1 Network management and bridging  802.2 Logical link control  802.3 Ethernet and fast Ethernet  802.4 Token bus  802.5 Token ring  802.7 Broadband  802.8 Fiber – optics  802.9 Integrate data and voice  802.10 Security and privacy  802.11 Wireless LAN  802.16 WiMAX (Broadband Wireless Access)
DIFFERENT TYPES OF NETWORKS  Local Area Network (LAN)  Metropolitan Area Network (MAN)  Wide Area Network (WAN)
LOCAL AREA NETWORK (LAN)  A network confined to a single location e.g. one building or one complex  Used for Sharing  Hardware e.g. Printers  Software  Data  Maximum distance limited by signal strength
LOCAL AREA NETWORK (LAN) …
METROPOLITAN AREA NETWORK (MAN)  A network that covers an entire city  Usually Cable is signal carrier  Maximum range of about 75 kilometers (45 miles) or so, and with high-speed transmission capabilities  T3 = 45 megabits per second (Mbps)  Unlike LANs, MANs generally include provisions for both voice and data transmissions.
WIDE AREA NETWORK (WAN)  A Network spread over wide areas such as across cities, states or countries  High speed data lines used to connect LANs in separate geographical locations  Communication using telephone lines, satellite or Microwave links  WANs can be centralized or distributed  More accurately wide-area internetworks(WAIs)
REQUIREMENTS FOR NETWORK  Server – Win NT/2000/2003, Unix/Linux, Netware  Client – Win XP, Win NT/2000, Linux, DOS  NIC – Ethernet  Transmission media – twisted pair, coaxial cables, fiber optics  Topology – bus, ring, star, tree  Protocol – TCP/IP  Interconnection devices – Hub, switch, router, bridge, gateway
INTERCONNECTION DEVICES
APPLICATIONS  Internet  Email  Downloads  E - Commerce  Group Chatting  Internet Telephony (VoIP)  Video Conferencing  IPTV  Internet Radio  Server based audio & video services
SECURITY  Firewall  Antivirus
TYPES OF MALWARE  Viruses: Code that attaches itself to programs, disks, or memory to propagate itself  Worms: Installs copies of itself on other machines on a network, e.g., by finding user names and passwords  Trojan horses: Pretend to be a utility. Convince users to install on PC  Spyware: Collect personal information  Hoax: Use emotion to propagate, e.g., child's last wish
THANK YOU

More Related Content

Computer networking (nnm)

  • 2. NETWORKING OF COMPUTERS  What is computer network?  Why we need a computer network ?  How a computer network works ?  Network models  IP Addressing  Network Topology  Different type of network  Requirements for network  Applications  Security
  • 3. WHAT IS NETWORK ?  Interconnection of computers  How to interconnect ?  Links required for interconnecting „N‟ nodes  Suitable ?  Solution ?
  • 4. GOALS OF THE NETWORKING  Resource Sharing  Information/Data Sharing  Centralized Computing  Remote Computing  Communication – Mail, Video Conferencing  Improving Security  Managing Tasks and Applications
  • 6. THE PRESENT : CONVERGENCE
  • 7. THE FUTURE : INTERNET AS PLATFORM
  • 8. SOME BASICS  Why a computer network is required ?  Data transfer  How to identify a node in network ?  IP address  How data flows in networks ?  Packet form  What is Packet switching ?  Statistical Multiplexing ReceiverSender Packet Transmission
  • 9. SOME BASICS……..  Channel capacity = Maximum data rate for a channel  Nyquist Theorem:  Bandwidth = W  Data rate =< 2W  Bilevel encoding:  Data rate = 2 X Bandwidth  Multilevel encoding:  Data rate = 2 X Bandwidth X log 2 M  For example if M = 4, Capacity = 4 X Bandwidth  Shannon‟s Theorem:  Maximum number of bits/sec = W log2 (1+S/N)  For telephone line: S/N = 30 dB, W = 3K; Capacity = 30Kbps
  • 10. TREND: TRAFFIC > CAPACITY Expensive Bandwidth Cheap Bandwidth Sharing No sharing Multicast Unicast Needs QoS QoS is not an issue Wireless LAN Possible in LAN
  • 11. NETWORK MODELS  Network models  OSI  TCP/IP  Connection oriented protocol  Connectionless protocol
  • 12. OSI REFERENCE MODEL  The seven layers  Each layer hides complexity of lower layer  Layering enforces modularity
  • 13.  End-to-end layer: top 4 OSI layers  Network layer: OSI network layer  Link layer: bottom 2 OSI layers  A-P-S-T are implemented in software  N-D-P are implemented in hardware THE SEVEN LAYERS
  • 14. THE SEVEN LAYERS ………….  Physical layer  Transmission of bit stream over physical medium  Coding scheme, connector shape and size, bit-level synchronization  Data link layer  Reliable transfer of information across the physical link  Sends blocks - frames  Medium access control (MAC): data link-layer address and access to the medium  Logical link control: link error control and flow control  Ethernet card: physical and data link layers
  • 15. THE SEVEN LAYERS ………….  Network layer  Concatenate logically a set of links to form an end-to- end link.  Compute a route  Segmentation and reassembly  Unique network-wide addresses : IP address  The beauty of IP is that we can layer it over any data link layer technology  Type-of-service in the IP
  • 16. THE SEVEN LAYERS ………….  Transport layer  Create the abstraction of an error-controlled, and flow-controlled, end-to-end link  Multiplex multiple applications to the same end-to-end connection  Port number
  • 17. THE SEVEN LAYERS ………….  Best-effort network layer - drops packets - delays packets - reorders packets - corrupts packet contents  Many applications want reliable transport - all packets reach receiver… …in order they were sent - no data corrupted - “reliable byte stream”  Need a transport protocol, e.g., Internet‟s Transmission Control Protocol (TCP)
  • 18. PRINCIPLES OF RELIABLE DATA TRANSFER  Important in application, transport, and link layers  Top-10 list of important networking topics! Sending Process Receiving Process Reliable Channel Sending Process Receiving Process Unreliable Channel RDT protocol (sending side) RDT protocol (receiving side) Application Layer Network Layer Transport Layer  Characteristics of unreliable channel will determine complexity of reliable data transfer protocol
  • 19. THE SEVEN LAYERS ………….  Session layer  provides the control structure for communication between applications  The Internet does not have a standard session layer protocol.  Presentation layer  deals with data  encrypt data  The Internet does not support a standard presentation layer.  Application layer  Provides access to the users  WWW: browser, server, navigation  file transfer using TCP  real-time audio and video retrieval using UDP
  • 20. TCP/IP MODEL  TCP/IP protocol consists of four/five layers  The lower layers correspond to the layer of the OSI model.  The application layer of the TCP/IP model represents the three topmost layers of the OSI model  TCP/IP is based on two principles  IP Over everything  end to end
  • 21. TCP/IP MODEL………..  TCP – Transmission Control Protocol  IP – Internet Protocol (Routing) TCP/IP Model TCP/IP Protocols OSI Ref Model Physical Datalink Network Transport Session Presentation Application Physical Datalink Network Transport Session Presentation Application Host to Network Network Transport Application Host to Network Network Transport Application UDP HTTPTelnet Point - to - Point Packet Radio Ethernet IP TCP FTP UDP HTTPTelnet Point - to - Point Packet Radio Ethernet IP TCP FTP
  • 22. ADVANTAGE OF TCP/IP MODEL  Open Protocol Standards  Independent of actual physical network & Computer hardware or software. Run over Ethernet/ Token Ring/ Modems/ Unix/ Windows PCs  Uses Common Global address scheme (IP addressing) that enables global connectivity
  • 23. IP ADDRESSING  IP addressing scheme is integral to the process of routing IP datagram through an internetwork.  Each IP address has specific component and follows a basic format.  These IP addresses can be subdivided and used to create addresses for sub networks.  Each host on a TCP/IP network is assigned a unique 32-bit logical address that is divided into two main parts: the network number and the host number.  The network number identifies a network and must be assigned by the internet Network Information Center (InterNIC) if the network is to be part of the internet.
  • 24. IP ADDRESSING  An Internet Service Provider (ISP) can obtain blocks of network addresses from InterNIC and can itself assign address space as necessary.  The host number identifies a host on a network and is assigned by the local network administrator.
  • 25. IP ADDRESSING  Class D and E are reserved for multicasting and research
  • 26. IP ADDRESSING - SUBNETTING
  • 28. COMPONENTS OF A NETWORK  Server :Computer that provides shared resources to network users.  Clients :Computer that access shared network resources provided by server.  Media : Way of connecting computers. e.g. Cable, fiber optics, telephone line.  Resources: Files, printers or other items to be used by network users.
  • 29. NETWORK ARCHITECTURES  Client-server  Peer-to-peer (P2P)  Hybrid of client-server and P2P
  • 30. CLIENT-SERVER ARCHITECTURE server:  always-on host  permanent IP address clients:  communicate with server  may be intermittently connected  may have dynamic IP addresses  do not communicate directly with each other client/server
  • 31. P2P ARCHITECTURE  no always-on server  users directly communicate  peers are intermittently connected and change IP addresses Highly scalable but difficult to manage peer-peer
  • 32. HYBRID OF CLIENT-SERVER AND P2P Skype  voice-over-IP P2P application  centralized server: finding address of remote party  client-client connection: direct (not through server) Instant messaging  chatting between two users is P2P  centralized service: client presence detection  user registers its IP address with central server when it comes online  user contacts central server to find IP addresses of buddies
  • 33. NETWORK TOPOLOGY  Defines the way in which computers, printers, and other devices are connected.  Describes the layout of the wire and devices as well as the paths used by data transmissions.
  • 34. BUS TOPOLOGY  All the devices on a bus topology are connected by one single cable  At a time only one host can send messages  Passive topology. Hosts on the bus are not responsible for moving data  Failure of any host doesn‟t affect the Network
  • 35. STAR & TREE TOPOLOGY  Commonly used architecture in Ethernet LAN  Larger networks use the extended star topology also called tree topology
  • 40. IEEE 802 STANDARDS  802.1 Network management and bridging  802.2 Logical link control  802.3 Ethernet and fast Ethernet  802.4 Token bus  802.5 Token ring  802.7 Broadband  802.8 Fiber – optics  802.9 Integrate data and voice  802.10 Security and privacy  802.11 Wireless LAN  802.16 WiMAX (Broadband Wireless Access)
  • 41. DIFFERENT TYPES OF NETWORKS  Local Area Network (LAN)  Metropolitan Area Network (MAN)  Wide Area Network (WAN)
  • 42. LOCAL AREA NETWORK (LAN)  A network confined to a single location e.g. one building or one complex  Used for Sharing  Hardware e.g. Printers  Software  Data  Maximum distance limited by signal strength
  • 43. LOCAL AREA NETWORK (LAN) …
  • 44. METROPOLITAN AREA NETWORK (MAN)  A network that covers an entire city  Usually Cable is signal carrier  Maximum range of about 75 kilometers (45 miles) or so, and with high-speed transmission capabilities  T3 = 45 megabits per second (Mbps)  Unlike LANs, MANs generally include provisions for both voice and data transmissions.
  • 45. WIDE AREA NETWORK (WAN)  A Network spread over wide areas such as across cities, states or countries  High speed data lines used to connect LANs in separate geographical locations  Communication using telephone lines, satellite or Microwave links  WANs can be centralized or distributed  More accurately wide-area internetworks(WAIs)
  • 46. REQUIREMENTS FOR NETWORK  Server – Win NT/2000/2003, Unix/Linux, Netware  Client – Win XP, Win NT/2000, Linux, DOS  NIC – Ethernet  Transmission media – twisted pair, coaxial cables, fiber optics  Topology – bus, ring, star, tree  Protocol – TCP/IP  Interconnection devices – Hub, switch, router, bridge, gateway
  • 48. APPLICATIONS  Internet  Email  Downloads  E - Commerce  Group Chatting  Internet Telephony (VoIP)  Video Conferencing  IPTV  Internet Radio  Server based audio & video services
  • 50. TYPES OF MALWARE  Viruses: Code that attaches itself to programs, disks, or memory to propagate itself  Worms: Installs copies of itself on other machines on a network, e.g., by finding user names and passwords  Trojan horses: Pretend to be a utility. Convince users to install on PC  Spyware: Collect personal information  Hoax: Use emotion to propagate, e.g., child's last wish