© 2007 Cisco Systems, Inc. All rights reserved. Cisco PublicITE PC v4.0Chapter 1 1

Addressing

ITE PC v4.0Chapter 1 2© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Objectives

Addressing in the LAN

IP addresses

MAC addresses

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Addressing

Data = payload = what we pay for

Data

Envelope: IP addresses on it

Mailbag: MAC addresses on it

Frame

Packet

Letter

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Addressing

Data

IP Dest: 192.168.1.2, IP Src: 192.168.3.2

MAC Dest: 00:00:00:00:03:01, MAC Src: 00:00:00:00:03:02

Frame

Packet

Letter

ITE PC v4.0Chapter 1 5© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Addressing

Data

IP Dest: Helsinki School, IP Src: VM School

MAC Dest: Berlin Post Office, MAC Src: Prague Post Office

Frame

Packet

Let‘s send a letter from VM School to Helsinki School via Prague and Berlin.

Frame is mailbag, Packet is envelope, Data is Letter.

Letter

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Addressing

The frame is

- Secretary‘s bag between VM School and VM Post Office

- mailbag between VM and Prague

- another mailbag between Prague and Berlin

- another mailbag between Berlin and Helsinki

- Postman‘s bag between Helsinki Post Office and Helsinki School

Letter

Pac

ket =

Env

elop

e w

ith L

ette

r

rem

ains

alw

ays

the

sam

e !!!

ITE PC v4.0Chapter 1 7© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Addressing

Packet = Envelope with Letter

remains always the same !!!

Letter

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Addressing

Data = payload = what we want to transport

Packet

Frame

ITE PC v4.0Chapter 1 9© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Addressing

Let‘s ping from PC2 to PC1:

ping 192.168.1.2

ITE PC v4.0Chapter 1 10© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Addressing

Each PC, each interface has its own

• IP address, which can be changed

• MAC address, which cannot be changed

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Addressing

IP is always the same !!!

Frame 1

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Addressing

IP is always the same !!!

Frame 2

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Addressing

IP is always the same !!!

Frame 3

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IP Addressing

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MAC Addressing

MAC address

• burned into ROM permanently

• cannot be changed

• 48 bits

• hexadecimal notation

• example: 00:60:2F:3A:07:BC

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MAC Addressing

48 bits

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Summary Frame

• changes between „stations“

Packet• stays always the same during its travel

IP address• 32 bits

• dotted-decimal notation

• „written“ on packet – doesn‘t change during transportation

• logical – device‘s IP can be changed

MAC address• 48 bits

• hexadecimal notation

• „written“ on frame - changes during transportation

• physical – device‘s MAC cannot be changed