1 / 40

Computer Science Overview Chap4-Networking and the Internet (2)

Computer Science Overview Chap4-Networking and the Internet (2). JainShing Wu. Networking Topology. The layout of the interconnections of the nodes of a computer network Types Bus Star Token ring Mesh. Bus Network. A set of clients are connected via a shared communications line

nani
Download Presentation

Computer Science Overview Chap4-Networking and the Internet (2)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Computer Science OverviewChap4-Networking and the Internet (2) JainShing Wu

  2. Networking Topology • The layout of the interconnections of the nodes of a computer network • Types • Bus • Star • Token ring • Mesh

  3. Bus Network • A set of clients are connected via a shared communications line • Ethernet • Advantage • Easy to setup • Disadvantage • Reconfiguration, fault isolation and installation of new devices tends to be difficult • A fault along the shared communication line stops all transmissions in the network

  4. BUS Network

  5. Star Network • Consists of one central switch, hub or computer to which all other nodes are connected • Client and Server

  6. Star Network • Advantage • Better performance • Isolation of devices • Benefits from centralization • Easy to detect faults and to remove parts • No disruptions to the network when connecting or removing devices • Installation and configuration is easy • Disadvantage • High dependence of the system on the functioning of the central hub • Failure of the central hub renders the network inoperable

  7. Star Network

  8. Token Ring • Each node connects to exactly two other nodes, forming a ring • Fiber Distributed Data Interface (FDDI)

  9. Token Ring

  10. Mesh Network • Each node captures and disseminates its own data, but also serve as a relay for other nodes • Mobile ad hoc networks (MANET)

  11. Mesh Network

  12. Ethernet • Computer networking technologies for local area networks (LANs) • Ethernet was commercially introduced in 1980 and standardized in 1985 as IEEE 802.3 • Several wiring and signaling variants of the OSI physical layer in use with Ethernet

  13. Ethernet • The original 10BASE5 Ethernet used coaxial cable as a shared medium

  14. Ethernet • Hub • Bridge • Switch • Router

  15. Ethernet Hub • A device for connecting multiple Ethernet devices together and making them act as a single network segment • Multiple input/output (I/O) ports

  16. Bridge • Network equipment to allow two or more communication networks, or two or more network segments

  17. Switch • Operate at one or more layers of the OSI model including data link and network • Operates simultaneously at more than one of these layers

  18. Switch

  19. Router • A device that • Forwards data packets between computer networks • Creating an overlay internetwork • Connected to two or more data lines from different networks

  20. Router • Reads the address information in the packet to determine its ultimate destination • Using information in its routing table or routing policy, it directs the packet to the next network on its journey

  21. Router

  22. Internet Protocol Suite • A set of communications protocols used for the Internet and similar networks • OSI seven layers • Known as • Transmission Control Protocol (TCP) • Internet Protocol (IP)

  23. OSI Seven Layers

  24. Physical Layer • Defines electrical and physical specifications for devices • Defines the relationship between a device and a transmission medium • Copper cable • Fiber optical cable • Includes the layout of pins, Voltages, line impedance, cable specifications, signal timing, hubs, repeaters, network adapters, host bus adapters

  25. Data Link Layer • Provides the functional and procedural means to transfer data between network entities • Detect possibly errors that may occur in the physical layer • Intended for • Unicasts • Multicasts • Broadcasts

  26. Network Layer • Provides the functional and procedural means of transferring variable length data sequences from host (source) to host (destination) • Maintains the quality of service (QoS) requested by the transport layer • Performs • Network routing functions • Fragmentation and reassembly • Report delivery errors

  27. Network Layer • Divided into three sub-layers: • Subnetwork access –considers protocols that deal with the interface to networks • Subnetwork-dependent convergence – when it is necessary to bring the level of a transit network up to the level of networks on either side • Subnetwork-independent convergence – handles transfer across multiple networks

  28. Transport Layer • Provides transparent transfer of data between end users • Provides reliable data transfer services to the upper layers • Controls the reliability of a given link through flow control, segmentation/desegmentation, and error control

  29. Session Layer • Controls the dialogues (connections) between computers • Establishes, manages and terminates the connections between the local and remote application

  30. Presentation Layer • Establishes context between application-layer entities • Provides a mapping between the application-layer entities that may use different syntax and semantics • Presentation service data units are encapsulated into session protocol data units, and passed down the stack

  31. Application Layer • Is the OSI layer closest to the end user • Both the OSI application layer and the user interact directly with the software application • Identify communication partners, determine resource availability, and Synchronizing communication

  32. Transmission Control Protocol (TCP) • One of the core protocols of the Internet Protocol Suite • The protocol used by major Internet applications • Provides reliable, ordered delivery of a stream of octets from a program on one computer to another program on another computer

  33. Transmission Control Protocol (TCP) • The protocol corresponds to the transport layer • Provides a communication service at an intermediate level between an application program and the Internet Protocol (IP)

  34. Transmission Control Protocol (TCP) • Detect the problem • IP packets can be lost, duplicated, or delivered out of order • Requests retransmission of lost data • Rearranges out-of-order data • Helps minimize network congestion • A reliable stream delivery service that guarantees all bytes received identical with bytes sent and in the correct order

  35. Internet Protocol (IP) • Aprincipal communications protocol used for relaying datagrams (network packets) across an internetwork • It is the primary protocol that establishes the Internet • Deliver datagrams from the source host to the destination host based on the addresses

  36. Internet Protocol (IP) • The primary protocol in the network layer • Address hosts and route datagrams (packets)

  37. Internet Protocol (IP) • Datagram construction • Each datagram has two components, header and payload • Header • Source IP address, Destination IP address, and other meta-data needed to route and deliver the datagram • Payload • the data to be transported • This process of nesting data payloads in a packet with a header is called encapsulation

  38. Internet Protocol (IP) • IP address and routing algorithms • IP Addressing refers to • How end hosts are assigned IP addresses • How subnetworks of IP host addresses are divided and grouped • Routing algorithms • Routing is performed by all hosts, but most importantly by routers • Routing algorithms decide how to move datagrams among networks

  39. Network Application • Email • WWW • telnet • ftp • Net TV

  40. Question?

More Related