Data transfer through the internet (OSI Model) (Open Systems Interconnection model)

Outline Introduction. Objective. The Seven Layers of OSI. How the seven layers work IP and Mac transition Conclusion

Introduction when you chat to somebody on the Net or send them an e-mail, do you ever stop to think how many different computers you are using in the process? There's the computer on your own desk, of course, and another one at the other end where the other person is sitting, ready to communicate with you. But in between your two machines, making communication between them possible, there are probably about a dozen other computers bridging the gap. Collectively, all the world's linked-up computers are called the Internet. How do they talk to one another? Let's take a closer look!

Objective How data transfer through internet

The Seven Layers of the OSI Model Define how the applications within the end stations will communicate with each other Lesson Aim <Enter lesson aim here.> Define how data is transmitted end to end.

https Client Receiver Server Sender Public Internet Need google.com Port (xxxx) Port 443 Server Sender Public Internet Need google.com https Port 443 Lesson Aim <Enter lesson aim here.> Router Client Client

How the seven layers work ?

Client Server Router

www.google.com L7 L6 L5 Example protocols Provides a user interface Sender www.google.com Data Example protocols Provides a user interface https, http, DNS, FTP, Telnet L7 Port () D Port (XX, 443 ) https Presents data. Data translation and formatting L6 SSL, SSH A P D Keeps different applications’ data separate Dialog control between devices (PPTP). L5 Netbios, PPTP S A P D

L4 L3 L2 L1 P P P Segment P IP, ICMP, EIGRP, OSPF P Packet Frame Bits D Reliable or unreliable delivery. Error correction. L4 TCP, UDP TCP S A P D Segment IP, ICMP, EIGRP, OSPF L3 Provides logical addressing. IP T S A P D Packet access to media using MAC address. Error detection. L2 ARP, RARP, PPP MAC N T S A P D Frame Specifies voltage, wire speed. Move bits. L1 DSL, 802.11, Ethernet 01 D N T S A P Bits 10011010110001010 Router

IP and Mac transition Public Internet Ip source S Mac A1 Mac A2 Mac B2 Mac C1 Ip_Destination D Mac C2

www.google.com Port 443 TCP Ip4_D Mac C2 101001101

Conclusion The Seven Layers of the OSI Model is responsible for transferring data through the internet . We saw how the data processed through transmissions . The IP address of the source and destination is constant but the Mac address is varied from machine to another.

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