Chapter 3 Understanding the OSI Model

Chapter 3 Overview Understanding the OSI Model Understanding the TCP/IP Model Mapping devices on the OSI and TCP Models Mapping Protocols on the OSI and TCP/IP Models 2

Understanding the OSI Model The seven layers of the OSI Model 3

Understanding the OSI Model Layers interact only with adjoining layers Encouraged creation of industry standards Network communication processes are segmented 4

Understanding the OSI Model Mnemonics to remember the layers 5

Application Layer DNS HTTP FTP TFTP DHCP LDAP POP3 SMTP IMAP SNMP SMB 6

Presentation Layer Determines how to format and present the data 7

Session Layer Maintains and Terminates Sessions Simplex Half-duplex Full-duplex 8

Transport Layer Handles flow control, reliability, and error checking TCP Connection-oriented Three-way handshake UDP Connectionless Best effort 9

Introducing Ports Logical ports Physical ports 65,536 TCP ports 65,536 UDP ports Used by services Physical ports On computers, routers, switches Cables plug into these ports 10

Network Layer Determines best route to destination IPv4 IPv6 ARP IGMP ICMP ICMP IPSec RIP OSPF 11

Data Link Layer Logical Link Control Media Access Control (LLC) IEEE 802.2 Media Access Control (MAC) IEEE 802.3 PPTP L2TP Token Ring ATM Frame Relay 12

MAC Addresses 13

Putting it Together Data travels up and down the OSI Model 14

Packets and Frames Names of data at different layers 15

Understanding the TCP/IP Model Four Layers Application Layer Transport Layer Internet Layer Link Layer 16

Mapping Devices Physical layer 17

Mapping Devices Data Link layer 18

Mapping Devices Network layer 19

Mapping Devices Application layer 20

Mapping Protocols on the OSI and TCP/IP Models 21

Chapter 3 Summary Understanding the OSI Model Understanding the TCP/IP Model Mapping devices on the OSI and TCP Models Mapping Protocols on the OSI and TCP/IP Models 22