Wide area networks
1 / 25

Wide Area Networks - PowerPoint PPT Presentation

  • Uploaded on

Wide Area Networks. CS 363 DePaul University. Questions on Final?. Group Evaluations. 25 points per group member, including yourself Distribute total number of points across group members as you see fit Hand in now. Wide Area Networks. Defined=> Transmission strategies: PSTN

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Wide Area Networks' - avital

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Wide area networks

Wide Area Networks

CS 363

DePaul University

Group evaluations
Group Evaluations

  • 25 points per group member, including yourself

  • Distribute total number of points across group members as you see fit

  • Hand in now

Wide area networks1
Wide Area Networks

  • Defined=>

  • Transmission strategies:

    • PSTN

    • Leased circuits

    • Fiber

    • Microwave/Satellite

    • Wireless

    • Internet

Wide area networks

  • Enterprise Networks

    • DePaul’s network

  • Global Networks

    • The Internet

Pstn connectivity
PSTN Connectivity

  • Circuits come in from CO

  • Connect at Demarc in building

  • Provide following services:

Pstn services
PSTN Services

  • Switched 56

  • X.25

  • T1

  • T3

  • Frame Relay

  • SMDS

  • ISDN

  • ATM

Wide area networks

  • multiprotocol

  • negotiates and registers IP assignments on dial-up

  • negotiates header compression

  • relatively good security

Wide area networks

  • only TCP/IP

  • requires manual IP registration

  • no security

  • not really faster than PPP


  • You are responsible for setting up some remote workstations and a server that will be connected to the Internet. The workstations will be connecting to the server using standard telephone ines. You know that SLIP and PPP are useful protcols for your situation. Your boss comes in and says, “I think SLIP is the protocol we should start using here. What do you think?” What protocol would you recommend? List three advantages to the recommended protocol.

Circuit switching
Circuit Switching

  • like voice call on PSTN

  • dedicated channel-always up

  • no channel access delay

  • inefficient use of transmission media

  • requires more bandwidth

  • connection delays

Message switching
Message Switching

  • no dedicated path

  • messages contain source and destination info

  • also referred to as store-and-forward networking

  • ex: e-mail

Message switching cont
Message Switching, cont.

  • Pros:

    • efficient traffic management through prioritization

    • reduction of network traffic congestion

    • efficient use of data channels

    • asychronous communication across time zones

  • Cons:

    • delays caused by store-n-forward

    • unsuitable for real-time applications

Packet switching
Packet Switching

  • Advantages of circuit and message switching without any of the disadvantages

  • Independent routing of packets

    • bandwidth/load balancing

    • dynamic rerouting

  • Packet size restricted for efficiency and speed

Datagram packet switching
Datagram Packet Switching

  • post-office analogy

Virtual circuit packet switching
Virtual Circuit Packet Switching

  • Virtual circuit (logical connection)

  • All packets between the same start and end point use same logical connection (route)

  • Used primarily for real-time, connection-oriented services like video and audio

Planning for packet switching
Planning for Packet Switching

  • Pros

    • PS improves use of network bandwidth

    • PS has shorter transmission delays than circuit switching because of small packet size

  • RAM vs. Hard drive=>PS requires more RAM; MS requires more hard drive space

  • Processor=>PS requires more processing power than MS

  • Lost Packets=>sequencing


  • Dial-up

  • Dedicated Analog

Connections cont
Connections, Cont.

  • Digital

    • T-carrier

    • Switched 56