OSI and TCP/IP Model

OSI Model

Open Systems Connection

TCP/IP Layer 1

Network Interface (Combines OSI layers 1 & 2)

TCP/IP Layer 2

Network

TCP/IP Layer 3

Transport

TCP/IP Layer 4

Application (Combines OSI Layers 5,6,7)

Physical Layer

• Mostly the Hardware Layer where physical signals/BITS are sent through the cables and fiber (signaling, cabling, connectors, punch-downs, loopback, hubs) contains DSL,ISDN, NIC,

Data Link Layer

• The “Switching /MAC Address Layer” Device to Device communication

  (ARP,PPP,HDLC) FRAME Relay /Bridge

Network Layer

• The “Routing/ IP Address Layer ” Routers use destination IP’s to forward traffic. Turns Segments into Packets from Transport Layer then reassembles them. (IP,IPX,IPSec,RIP,ICMP)

Transport Layer

• The “Post Office” Layer; Responsible for ensuring that data packets are delivered accurately and reliably between the sender and receiver (TCP/UDP) are used here. SEGMENTS packets for the Network layer

Session Layer

• Initiates, Stops, and Restarts the movement of Data. Manages communication between devices. Control Protocol layer (NFS, SQL, PPTP, NetBios, PAP, SCP) Tunneling

Presentation Layer

• Encrypts and Decrypts Data - Translates/Formats data for the Application Layer (SSL,ASCII,JPEG,MIDI,MPEG,GIF,MP3,MP4)

Application Layer

• The Layer we See, Allows users to interact with the application (HTTP,FTP,IMAP,DNS,) application software.

Application Layer

• HTTP,FTP,IMAP,DNS

Presentation Layer

• SSL,ASCII,JPEG,MIDI,MPEG,GIF,MP3,MP4

Session Layer

• NFS, SQL, PPTP, NetBios, PAP, SCP

Transport Layer

• TCP/UDP

Network Layer

• IP,IPX,IPSec,RIP,ICMP

Data Link Layer

• ARP,PPP,HDLC

Physical Layer

• DSL,ISDN, NIC,