PRACTICAL

INTRODUCTION TO INTERNET TECHNOLOGY

Practical one

PACKET DELAY AND LOSS IN INTERNET

• In this experiment, you will observe real delays and loss inherent in internet.

• Also all the paths a packet will pass through from source to destination

3

“Real” Internet delays and routes

• What do “real” Internet delay & loss look like? • Traceroute program: provides delay measurement

from source to router along end-end Internet path towards destination. For all i:– sends three packets that will reach router i on path towards

destination– router i will return packets to sender– sender times interval between transmission and reply.

3 probes

3 probes

3 probes

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“Real” Internet delays and routes

1 cs-gw (128.119.240.254) 1 ms 1 ms 2 ms2 border1-rt-fa5-1-0.gw.umass.edu (128.119.3.145) 1 ms 1 ms 2 ms3 cht-vbns.gw.umass.edu (128.119.3.130) 6 ms 5 ms 5 ms4 jn1-at1-0-0-19.wor.vbns.net (204.147.132.129) 16 ms 11 ms 13 ms 5 jn1-so7-0-0-0.wae.vbns.net (204.147.136.136) 21 ms 18 ms 18 ms 6 abilene-vbns.abilene.ucaid.edu (198.32.11.9) 22 ms 18 ms 22 ms7 nycm-wash.abilene.ucaid.edu (198.32.8.46) 22 ms 22 ms 22 ms8 62.40.103.253 (62.40.103.253) 104 ms 109 ms 106 ms9 de2-1.de1.de.geant.net (62.40.96.129) 109 ms 102 ms 104 ms10 de.fr1.fr.geant.net (62.40.96.50) 113 ms 121 ms 114 ms11 renater-gw.fr1.fr.geant.net (62.40.103.54) 112 ms 114 ms 112 ms12 nio-n2.cssi.renater.fr (193.51.206.13) 111 ms 114 ms 116 ms13 nice.cssi.renater.fr (195.220.98.102) 123 ms 125 ms 124 ms14 r3t2-nice.cssi.renater.fr (195.220.98.110) 126 ms 126 ms 124 ms15 eurecom-valbonne.r3t2.ft.net (193.48.50.54) 135 ms 128 ms 133 ms16 194.214.211.25 (194.214.211.25) 126 ms 128 ms 126 ms17 * * *18 * * *19 fantasia.eurecom.fr (193.55.113.142) 132 ms 128 ms 136 ms

traceroute: gaia.cs.umass.edu to www.eurecom.fr

Three delay measurements from gaia.cs.umass.edu to cs-gw.cs.umass.edu

* means no response (probe lost, router not replying)

trans-oceaniclink

INSTALL TRACEROUTE

• INSTALL THE Visual traceroute program in the folder provided.

• After installation: explore the software interface to have a feel of the commands available.

Exercise 1• Find the trace route from your computer to :• www.gaia.cs.umass.edu• www.eurecom.fr• www.yahoo.com• www.yahoo.ca• www.google.com.ng• www.google.com• Your school’s website• Record and save your observations in files

Exercise 2

• Traceroute: www.gaia.cs.umass.edu to www.eurecom.fr

www.yahoo.com to www.yahoo.cawww.google.com.ng to www.google.com

• Record and save your observations in files• How many hops were in each trace route?• How many ISP and peering points were in each

traceroute?• What other useful observations could you see

Practical Two

• Simulation of internet switching methods: packet-switching and message switching

In this practical you will see the way packets are sent over the internet. You will be able to adjust some parameters such as distance, propagation delay, packet size, etc.

Exercise 1

• Type the following address into your browser address bar:

http://wps.aw.com/aw_kurose_network_5/111/28536/7305312.cw/index.html

1. Play with the first three applets using various parameters of your choice.

2. Record your observations.3. What more understandings have you gained?

Practical ThreeDNS SERVER

• A server that maintains a database of IP address/computer name mappings.

• The DNS has the responsibility to resolve fully qualified domain names and other host names to IP addresses.

• In DNS, the clients are called resolvers and the servers are called name servers.

• WE SHALL USE nslookup UTILITY TO ACCESS DNS SERVER TO OBTAIN IP ADDRESSES

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requesting hostcis.poly.edu

gaia.cs.umass.edu

root DNS server

local DNS serverdns.poly.edu

1

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4

5

6

authoritative DNS serverdns.cs.umass.edu

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TLD DNS server

DNS name resolution example

• Host at cis.poly.edu wants IP address for gaia.cs.umass.edu

iterated query: contacted server replies

with name of server to contact

“I don’t know this name, but ask this server”

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requesting hostcis.poly.edu

gaia.cs.umass.edu

root DNS server

local DNS serverdns.poly.edu

1

2

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6

authoritative DNS serverdns.cs.umass.edu

7

8

TLD DNS server

3recursive query: puts burden of name

resolution on contacted name server

heavy load?

DNS name resolution example

nslookup

• The nslookup utility is used to find out the corresponding IP address of a host name by contacting Internet Domain Name Servers.

• It also does reverse name lookup and find the host name for a specified IP address.

• It has two modes: interactive and non-interactive. Interactive mode is used to get information about various hosts and domains or to displays a list of hosts in a domain.

• Non-interactive mode is used to display just the name and requested information for a host or domain.

Exercise 1

1. Locate nslookup program from the list of programs on your pc.

2. Hint: search for nslookup3. Run the nslookup program. It is a dos based

program4. Type in the followings and obtain the IP values:

i. www.yahoo.caii. www.google.com.ngiii. http://wps.aw.comiv. 216.240.187.102– Try some other web addresses & record your

observations

EXERCISE 2

• USING WEB BASED TOOLS TO ACCESS DNS SERVERS records

• TYPE THE FOLLOWING INTO YOUR BROWSER• http://www.network-tools.com/• REPEAT STEP 4 OF EXERCISE 1• Run: ping, DNS records, Express for

www.bellsuniversity.org• Record your observations• Try your hand on DNS Server applet at:

http://media.pearsoncmg.com/aw/aw_kurose_network_2/applets/dns/dns.html

Practical Four

Speed and Bandwidth TestIn this practical, you will be able to measure the speed, bandwidth, and

performances of your internet connection

INSTALL MY CONNECTION SPEED

• INSTALL THE my connection speed program in the folder provided.

• After installation: explore the software interface to have a feel of the commands available such as tools.

Exercise 1

Run application speed• Determine the • Upload and download speed, maximum

bandwidth, quality of service, RTT, and maximum delay of your internet connection.

Exercise 2

Run capacity speed• Determine the: • Upload and download speed, maximum

bandwidth, quality of service, Round Trip Time, and maximum delay of your internet connection.

SUBMISSION

SUBMIT YOUR OBSERVATIONS FOR ALL THE PRACTICAL YOU HAVE DONE USING

STANDARD LABORATORY REPORT FORMAT.

SUBMIT ELECTRONICALLY TO arulogundiran@gmail.com

• Use your matric number only as the subject heading of the mail