Course: Computer Networks 1
Autumn 2010
Philip Heimer
philip.heimer@hh.se
NETWORKING FUNDAMENTALS
Who am I?
Philip Heimer
Room: F320
US Robotics 28 800 modem
Global Traffic Map 08
Source:
http://www.telegeography.com/productinfo/map_traffic/index.php/images/traffic_m
ap08_large.jpg
Computer Networks Equipment
Can be divided into three different categories
End devices
Computers
PDA
IP phones
-
Media
- Intermediary devices
Copper cable
Optical fibre
Wireless
Routers
Switches
Hubs
End devices
Desktop computer
Androids
IP-phone
Personal Digital Assistant
PDA
Media
Console cable (aka rollover cable)
Serial cable
RJ 45-cable Shielded/Unshielded
Twisted Pair - TP
Fiber optical cable
Wireless
Copper wire
Optical Communication
The Internets Undersea World
Source:
http://www.sizzledcore.com/wpcontent/uploads/2008/07/internets-underseaworld.jpg
Wireless communication
Intermediary devices
Router
Switch
Hub
Network Representations
Local Area Network - LAN
One of the pods @ D5
Serial cable
Console connection
Consoleport on a device
You may configure your devices
using program such as Hyper
Terminal or Terra Term.
Cable to be used between the device and your
computer.
Bandwidth
Bandwidth
Limitations to different media.
Digital signals
Decoding of digital signals
going through an optical
medium.
Modulationtechniques
using wireless.
The binary number system – A
global language for electronic
devices.
Only uses one and zero
whereas in the decimal
system we use 0-9.
ASCII-table
Hello – 0100100001100101011011000110110001101111
See you! - 010100110110010101100101001000001111001011011110111010100100001
Communication
The Protocols of conversation help people to
successfully communicate.
Communication requires:
Sender and receiver
Communication medium
Common language
Rules that Govern
Communications
Cosmic Call was the name of two interstellar radio messages that were sent from
RT-70 in Yevpatoria in 1999 and 2003 to various nearby stars.
Networking Protocols describe
processes such as:
The format or structure of the message
The method by which networking devices
share information about pathways with other
networks
How and when error and system messages
are passed between devices
The setup and termination of data transfer
sessions
Networking Protocols
Networking Protocols
Networking Protocols
Networking Protocols
The Open Systems Interconnect
(OSI) model
Building networks is just like building a house.
Different layers representing different stages.
There may be different needs or solutions for
each stage. Like...
Foundation
Frames
Plumbing
Heating
Electricity
The Open Systems Interconnect
(OSI) model
All
People
Seem
To
Need
Data
Processing
Some protocols used at the
seven layers
An email travels through the
different layers.
Addressing and labeling the
packet
All devices need unique identifiers in order to be
able to communicate across the network.
Physical and logical addresses
MAC-address – Physical: ”Burnt” into the device.
Ex: 00-50-8D-9D-C2-A6
IP-address – Logical: ”temporarily assigned, may be
changed”.
Ex: 192.168.1.1
Packets being sent across the network must have a
source and destination header.
Addressing with IPv4
The IPv4-protocol is using a 32-bit binary field.
Logical topology
LAN – DreamHack
DH Physical Design
DreamHack
Winter 2007
Source:
http://dreamhack.biz/info/docs/dhsnet-stkj-eng-2.0.pdf
SNMPc – Simple Network
Management Protocol (Castle
Rock Computing)
Background image in SNMPc – Clear layout
over all tables at DreamHack
Source:
http://dreamhack.biz/info/docs/dhsnet-stkj-eng-2.0.pdf
Setting up a LAN – steps.
Devices
End devices, media, intermediary devices
Cabling
Copper cable, Wireless, Optical fibre
Configuring devices
Console connection, or via a web-interface using your
webbrowser.
Configure things such as ip-addresses, routing, security,
quality of service, redundancy etc.
IP-addressing
Configuring ports with IP-addresses on your end- and
intermediary devices.
Network Simulation Programs
Program:
Packet Tracer
GNS3
Cisco Packet Tracer
GNS3
Testing the connectivity
From your computer, go to the command
prompt and type ”ping” followed by the ipaddress/domain names you would like to test.
With the command tracert, you may look up the
path your packet will travel towards a
destination. You will see different routers on the
way.
A few important concepts
DHCP – Dynamic Host Configuration Protocol
Is used to automatically distribute IP-addresses to hosts
on the network.
For example your laptop computer is given the ip: 192.168.1.5
DNS – Domain Name System
Pairing ”user friendly” names with IP-addresses.
www.example.com – 192.0.32.10
ARP – Address Resolution Protocol
Pairing MAC- and IP-addresses in a table in order for
devices to quicker find the path to its destination.
Try typing « arp –a » in the command prompt.
MAC: ABCDEF000002
IP: 169.254.0.2
Next week - Tuesday
IP-addressing
Subnetting