OSI and TCP/IP models

What does OSI stand for?

Open Systems Interconnection reference model

OSI pneumonic?

All people seem to need data processing

Layer 1 Name

Physical Layer

Layer 1 Definition

Signaling, Cables, Connectors, hubs

No Protocols

Tests for Layer 1

Run Loopback tests

Replace cables

Replace NIC

Layer 2 Name

Data Link Control (DLC)

Layer 2 definition

Switching Layer

Basic network language

MAC address

What does MAC stand for?

Media Access Control or

EUI (Extended Unique Identifier)

Layer 3 definition

Routing Layer

IP addresses

Packets

Fragments frames

Layer 3 name

Network Layer

What does IP stand for?

Internet Protocol

Layer 4 name

Transport Layer

Layer 4 definition

Post Office Layer

TCP

UDP

What does TCP stand for?

Transmission Control Protocol

What does UDP stand for?

User Datagram Protocol

Layer 5 name

Session Layer

Layer 5 defintion

Communication between devices. start,stop,restart

Maintain sessions between devices

Tears down sessions

half duplex, full duplex

Control protocols

Tunneling protocols

Layer 6 name

Presentation Layer

Layer 6 definition

Encrypting

SSL/TLS

Character encoding

Often combined with layer 7

Layer 7 name

Application Layer OSI

Layer 7 definition

Layer we see on screen

HTTP,FTP,DNS,POP3

TCP/IP Protocol Suite common name

Internet Protocol Suite

4 TCP/IP Layers

Application

Transport

Internet

Link

Link Layer TCP/IP

OSI Layer 2

First thing that has to happen

ARP

Applies CSMA/CD or CSMA/CA and sends/receives packets

Internet Layer TCP/IP

OSI Layer 3

IPv4, IPv6, ICMP, IGMP

responsible for addressing, routing, and packaging data packets called IP datagrams.

Transport Layer TCP/IP

OSI Layer 4 (Transport layer)

TCP

UDP

Application Layer TCP/IP

OSI Layers 5,6,7

FTP, BOOTP, DNS, HTTP(S), TLS/SSL, POP3, IMAP4, SSH, VoIP,TELNET, SMTP,etc.

ARP

Address Resolution Protocol (MAC address)