OSI Model
description
Transcript of OSI Model
![Page 1: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/1.jpg)
OSI Model
CS363-Winter 1999
DePaul University
![Page 2: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/2.jpg)
Group Project Info
• Teams formed and on the web
• Cases
• Working in Groups
• Last half of class tonight reserved for projects
![Page 3: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/3.jpg)
Review #1
• You must connect a research institution’s main offices with the testing site 30 miles away. You will connect them with fiber optic cable. Which type of fiber will you use and why?
![Page 4: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/4.jpg)
Review #2
• You are replacing your thicknet backbone between your servers with a high-speed network cable. You are considering using Category 5 twisted-pair copper or multimode fiber cable. – Under what circumstances will you install the fiber?
– Under what circumstances will you not use fiber?
![Page 5: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/5.jpg)
Review #3
• Your company recently renovated its telephone system, including cabling, and had extra cable installed for future growth. Now you would like to use the excess cabling to network the computers in your company.– What sort of network performance (data capacity and
cable length) can you reasonable expect from these new telephone cables?
– What could you do with the old telephone cable that is still in the building?
![Page 6: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/6.jpg)
Review #4
• You would like to attach your notebook computer to your LAN, but it does not have a PCMCIA slot or a place for a proprietary network card. How can you attach it to the network?
![Page 7: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/7.jpg)
OSI Model
• Why do we keep talking about this? Why should we care?
![Page 8: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/8.jpg)
Protocol Stacks
• =>group of protocols arranged on top of each other as part of a communications process.
• Importance of protocol stacks
![Page 9: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/9.jpg)
Peer-Layer Communication Between Stacks
![Page 10: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/10.jpg)
Physical Layer
• Functions
• Components
![Page 11: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/11.jpg)
Data-Link Layer
• Functions
• Components
![Page 12: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/12.jpg)
Network Layer
• Functions
• Components: routers and gateways
![Page 13: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/13.jpg)
Transport Layer
• Functions
• Components
![Page 14: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/14.jpg)
Session Layer
• Functions
• Components
![Page 15: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/15.jpg)
Presentation Layer
• Functions
• Components
![Page 16: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/16.jpg)
Application Layer
• Functions
• Components
![Page 17: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/17.jpg)
Problem
• Your company wants to use data link layer encryption devices to send private data over a public wide area network. What effect will this have on devices in other layers?
![Page 18: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/18.jpg)
Problem
• When trouble-shooting your network with a packet sniffer, you find a device generating spurious TCP/IP packets. Which devices are suspect?
![Page 19: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/19.jpg)
Drivers
• =>
• NDIS
• ODI
![Page 20: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/20.jpg)
Network Protocols
• =>agreed-upon ways in which computers exchange information
![Page 21: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/21.jpg)
How Protocols Work
• Sending::– Packetize data– Appropriately address the packets– Present packets to the network for delivery
• Receiving:– -Accept packets from the network– Remove transmitting information (addresses) added
in the sending process– Reassemble data packets into original message
![Page 22: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/22.jpg)
Network Packets
• Packet Structure– Header=>
– Data=>
– Trailer=>
![Page 23: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/23.jpg)
Packet Assembly
• Routing
• Protocol Stacks
![Page 24: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/24.jpg)
Binding Protocols
![Page 25: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/25.jpg)
Two Types of Protocols
• Connection-Oriented • Connectionless
![Page 26: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/26.jpg)
Standard Protocol Stacks
• ISO/OSI
• SNA
• DECnet
• NetWare
• AppleTalk
• TCP/IP
![Page 27: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/27.jpg)
Microsoft Supported Transport Protocols
• NetBEUI
• NWLink
• TCP/IP
![Page 28: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/28.jpg)
Other Protocols whose names you should know
• SMTP
• SNMP
• NFS
• X.25
• X Windows
![Page 29: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/29.jpg)
Problem:
• Your boss wants you to speed up the office LAN without spending any money. You are currently using 10Mbps Ethernet and TCP/IP. Users connect to the Internet using dial-up modems, and a single Ethernet domain is in use. What do you do?
![Page 30: OSI Model](https://reader035.fdocuments.in/reader035/viewer/2022062722/56813ae8550346895da34cf1/html5/thumbnails/30.jpg)
Problem:
• Your company network has become very slow, so you decide to break it up into multiple domains and use a router to connect the domains. As soon as you disconnect the networks, even with the router running properly, you can’t get data between networks. You are using four Windows NT servers (one in each subnetwork) running on Ethernet with NetBEUI. You’ve spent your budget on the router and can’t afford to purchase new hardware. What is wrong? How can you fix it?