1 / 9

CS 455/555: Spring 2003

CS 455/555: Spring 2003. Chapter 1: Introduction. Uses of Computer Networks. Networks for Companies Networks for People Social issues. Network Hardware. Broadcast Networks versus Point-to-point Networks

tuyen
Télécharger la présentation

CS 455/555: Spring 2003

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. CS 455/555: Spring 2003 Chapter 1: Introduction

  2. Uses of Computer Networks • Networks for Companies • Networks for People • Social issues

  3. Network Hardware • Broadcast Networks versus Point-to-point Networks • Broadcast Networks: Local area networks (LAN), Metropolitan area networks (MAN), Wide-area networks (WAN), Wireless Networks, Internetworks (vs. intranetworks?) • See Figures

  4. Network Software • Protocol Hierarchies See Fig 1-9 through 1-11 • Design Issues for the Layers: Addressing; Rules of data transfer---Simplex, half-duplex, full-duplex; Error control; Ordering of messages; Flow-control---fast sender, slow receiver; message length; multiplexing and demultiplexing; routing • Interfaces and Services: SAP, IDU, SDU, PDU • See Figure 1-12

  5. Network Software (Contd.) • Connection-oriented and Connectionless Service • See Figure 1-13 • Service Primitives • See Figure 1-14 • Services vs. protocols: Services are offered by a layer to the layer above it; A protocol is a set of rules for communication between entities with the same layer

  6. Reference Models • The OSI Reference Model (See Fig. 1-16) • Seven layers: Physical, Datalink, Network, Transport, Presentation, and Application • Data transmission in the OSI protocol (See Fig. 1-17) • The TCP/IP Reference Model (See Fig. 1-18) • Four layers: Host-to-network, Network, Transport, Application (See Fig 1-19)

  7. Comparison of OSI and TCP Reference Models • Read pages 38-44 • It will be more obvious after we study the protocols

  8. ATM (Asynchronous Transfer Mode) • Asynchronous? The sender and receiver are not tied through a common clock • ATM cell: 53 bytes long: 5-byte header and 48-byte data data is sent in terms of cells • Connection-oriented networks: Cell delivery is not guaranteed but their order is (E.g., If 1-10 cells are sent in sequence, then only cells 1-5 and 7-9 may be received; but they are received in that order.) • ATM networks are organized like WANs with speeds of 155 Mbps (actually 155.52), 622 Mbps (4*155.5 = 622), and more.

  9. ATM (Contd.) • ATM Reference model (See Fig. 1-30) • User plane: Deals with data transport, flow control, error correction, and other user functions. • Control plane: Deals with connection management • (See Fig.1-31)

More Related