Computer Networks lab maual

8/18/2019 Computer Networks lab maual

1/35

A

C

collision

B

Exp No:1

Date:

SIMULATION OF CSMA/CD

Aim:

To simulate the CSMA/CD protocol using ViRtSim software and study its characteristics.

Theory:

Carrier sense multiple access is a network access method used on shared network topologies

such as thernet to control access to the network. De!ices attached to the network ca"le

listen#carrier sense$ "efore transmitting. %f the channel is in use& de!ices wait "efore transmitting.

All de!ices ha!e e'ual access to use the network when it is clear.

Collusion detection defines what happens when two de!ices sense a clear channel& then

attempt to transmit at the same time. A collision occurs and "oth de!ices stop transmission& wait

for a random amount of time and then retransmit. This is the techni'ue used to access the ()*.+

thernet network channel. This method handles collision as they occur& "ut if the "us is

constantly "usy& collision can occur so often that the performance drops drastically.

data to B data to


2/35

OUTPUT:


3/35


4/35


5/35

A

C

B

A

C

B

Coi!io" i" a "et#or$

Data to B

A%ter !pe&i%ied i"ter'a

data to C


6/35

A(orithm:

• Declare two frame !aria"les and assign them the data frames to "e transmitted.

• %nitiali,e the CSMA/CD function.

• Send data from node a to node " and sense multiple access.

• Send data from node " to node c and sense multiple access.• Check if collision occurs.

• %f collision occurs wait for -)))ms and then retransmit the two data from the nodes one

after the other.

• Stop the eecution.

Pro&ed)re:

• select programViRtsimsimulation CSMA CSMA/CD

• nter the program& sa!e and run it

*e!)t:

Thus the CSMA/CD protocol was simulated using ViRtsim software and its

characteristics was studied

Exp No: +


7/35

A

C

B

Date:

SIMUATION OF CSMA/CA

Aim:

To simulate the CSMA/CA protocol using ViRtSim software .

Theory:

Carrier sense multiple access is a network access method used on shared network

topologies such as thernet to control access to the network .de!ices attached to the network

ca"le listen#carrier sense$ "efore transmitting. %f the channel is in use& de!ice wait "efore

transmitting. Multiple access indicates that many de!ice can connect to and share the same

network. All de!ices ha!e e'ual access to use the network when it is clear.

Collision a!oidance defines what happens when two de!ices sense a clear channel& then

attempt to transmit the same time .a collision occurs and "oth de!ices stop transmission& wait for

a random amount of time and retransmit. This is techni'ue used to access the ()*.+ thernet

network channel .This method handles collision as they occur& "ut if the "us is constantly "usy&

collision can occur so often that the performance drops drastically.

RT

*e,)e!t to !e"d -*TS. !e"t to A


8/35

O)tp)t :


9/35

A

C

B

A

C

B

A

C

B

CT

Cear to !e"d -CTS. !e"t to A

data

Data tra"!mitted to B

AC

A&$"o#ed(e -AC. !e"t to A


10/35

A(orithm:

• Declare a frame !aria"le and assign them the data frame to "e transmitted.

• %nitiali,e the CSMA/CA function.

• 0odes keep listening to the channel.

• Send re'uest to send frame from node a to node ".• Send clear to send frame from node " to node a.

• Send data from node a to node " and sense multiple access.

• Send acknowledge frame from node " to node a.

• Stop the eecution.

Pro&ed)re:

• select programViRtsimsimulation CSMA CSMA/CA

• nter the program& sa!e and run it

*e!)t

Thus the CSMA/CA protocol was simulated using ViRtSim software.

1utput2


11/35

Exp No: 0

Date:


12/35

IMPLEMENTATION OF DISTANCE ECTO* *OUTIN2

Aim:

To implement and test the distance !ector routing using ViRtSim.

Theory:

%n distance !ector router shares its knowledge a"out the entire network with information

from its neigh"ors in a step procedure. 1nce this is complete it will ha!e a complete idea a"out

the network. The ta"le consists of network %D& cost and net hop. The cost refers to the num"er

of hop count #least$ to reach a particular destination. Routers using distance3!ector algorithms

send all or part of their routing ta"le entries to ad4acent routers on a periodic "asis. This happens

e!en if there are no changes in the network. 5y recei!ing a routing update& a router can !erify all

the know routes and make changes to its routing ta"le. This process is also known as 6routing "y

rumor7.

Pro&ed)re:

• 1pen ViRtSim and select simulationdistance !ector routing.

• Design the re'uired network "y including the routers& links and corresponding weights on

the links

• Select the sender and destination node and click the 6find path7.• Click the 6calculate7 "utton which displays all the route details and shows the shortest

route.

*e!)t:

Thus the distance !ector routing algorithm was implemented and simulated using

ViRtSim software.


13/35

O)tp)t:

Exp No:3

Date:


14/35

IMPLEMENTATION OF LIN STATE *OUTIN2

Aim:

To implement and test the link state routing using ViRtSim.

Theory:

%n link state routing e!ery router shows its knowledge a"out its neigh"or to the entire

network and ultimately all routers will ha!e a routing ta"le within the link state data"ase. 8ink3

state routing protocols respond 'uickly to network changes sending trigger updates only when a

network change has occurred. 8ink3state routing protocols send periodic updates& known as link3

state refreshes& at longer time inter!als& such ad!ertisement #8SA$ is concerning that link. The

8SA is then transmitted to all neigh"oring de!ices. ach routing de!ice takes a copy of the 8SA&

updates its link3state data"ase& and forwards the 8SA to all neigh"oring de!ices. This flooding of

8SAs is re'uired to ensure that all routing de!ices create data"ase that accurately reflect the

network topology "efore updating their routing ta"les

Pro&ed)re2

• 1pen ViRtSim and select simulation 8ink state routing.

• Design the re'uired network "y including the routers and links.

• Select the sender and destination node and click the 6find path9.

Click the 6calculate7 "utton which displays all the route details and shows the shortest

route

*e!)t:

Thus the link state routing algorithm was implemented and simulated using ViRtSim

software.


15/35

Ex No:4

Date:

FILE ENC*5PTION AND DEC*5PTION USIN2 PC TO PC COMMUNICATION

Aim:

To encrypt and decrypt file using pc to pc communication.

Theory:

%t is unlikely that system can completely present unauthori,ed access to transmission media. The

media used today is called encryption& means that the sender transform the original information

to another form and send resulting unintelligence message o!er the network. Decryption re!erses

"ack the original message. The sender uses an encryption algorithm and a key to transform plain

tet into cipher tet.

Pro&ed)re:

Step -2 1pen Vi3Rt sim and choose :C T1 :C 3;


16/35

Ex No:6

Date:

SIMULATION OF *IN2 TOPOLO25 USIN2 LAN T*AINE* IT

Aim:

To simulate the ring topology using 8A0 trainer kit and study its characteristics.

Theory:

%n ring topology& each de!ice has a dedicated point to point line configuration with the

two de!ices on either side of it. A signal is passed along the ring in one direction from de!ice tode!ice until it reaches its destination. ach de!ice in the ring incorporates a repeater. ?hen a

de!ice recei!es a signal intended for another de!ice its repeater regenerates the "it and passes

them along unidirectional traffic.

I LAN T*AINE* IT 7 *IN2 TOPOLO25

Pro&ed)re:


17/35

Step -2 Switch on the 8A0 trainer kit and gi!e connections as shown in the "lock diagram. The

0%C - is placed in programming mode.

Step *2 select ViRtSim in the :C and then the utilities.

Step +2 select ARM downloader and click read de!ice %D.

Step =2 reset the 0%C - and then the de!ice %D will "e read successfully.

Step >2 to load the ARM processor& select the respecti!e he "it file and click load flash.

Step @2 to load the


18/35

*e!)t:

Thus ring topology was implemented and simulated using V%38A0 trainer kit and ViRtSim

software.


19/35

Ex No: 7

Date:

SIMULATION OF BUS TOPOLO25 USIN2 LAN T*AINE* IT

Aim:

To simulate the "us topology using 8A0 trainer kit and study its characteristics.

Theory:

The "us topology connects each station on the network into something called the segment

trunk. A "us is usually referred to a ca"le that connects end to end and this is used to transmit thesignals from one end to the other end. At e!ery end a terminator is placed so that it understands

in which direction the data is tra!elling and also terminator is used to a"sor" the signals. %f the

terminator does not a"sor" the signal then the same signal is reflected "ack to the "us confusing

the whole data flow.

I LAN T*AINE* IT7 BUS TOPOLO25

Pro&ed)re:

Step -: Switch on the 8A0 trainer kit and gi!e connections as shown in the "lock diagram. The

0%C - is placed in programming mode.


20/35

Step *2 select ViRtSim in the :C and then the utilities.

Step +2 select ARM downloader and click read de!ice %D.

Step =2 reset the 0%C - and then the de!ice %D will "e read successfully.

Step >2 to load the ARM processor& select the respecti!e he "it file and click load flash.

Step @2 to load the


21/35

*e!)t:

Thus "us topology was implemented and simulated using V%38A0 trainer kit and ViRtSim

software.

Ex No:9


22/35

Date:

SIMULATION OF STA* TOPOLO25 USIN2 LAN T*AINE* IT

Aim:

To simulate the star topology using 8A0 trainer kit and study its characteristics.

Theory:

%n a star topology each de!ice has a dedicated point to point link only to a central

controller& usually called hu". The de!ices are not directly linked to each other. Fnlike a mesh

topology a star topology does not allow direct traffic "etween de!ices. The controller act as an

echange& it sends the data to the controller which then relays the data to the other connected

de!ice. %ts ad!antage includes ro"ustness. %f one link fails only that link is affected and all other link remains acti!e.

I LAN T*AINE* IT STA* TOPOLO25

Pro&ed)re:

Step -2 Switch on the 8A0 trainer kit and gi!e connections as shown in "lock diagram. The 0C%

- is placed in programming mode.

Step *2 Select ViRtSim in the :C and then the utilities.

Step +2 Select ARM downloader and click read de!ice %D.

Step =2 Reset the 0%C - and then the de!ice %D will "e read successfully.

)ode )ode)ode C

)ode (

)&C+ )&C)&C#


23/35

Step >2 To load the ARM processor& select the respecti!e he "it file and click load flash.

Step @2 To load the


24/35

Ex No:;

Date:

IMPLEMENTATION OF STOP AND


25/35

Pro&ed)re:

Step -2 connect the master/ser!er to the computer 0%C port.



Step =2 Reset the 0%C - then the de!ice %D will "e read successfully.


Step @2 To load the


26/35

*e!)t:

Thus the stop and wait protocol was implemented and simulated using V%38A0 trainer kit and

ViRtSim software.


27/35

Ex No:1=

Date:

IMPLEMENTATION OF 2O BAC N P*OTOCOL

Aim:

To implement and test the o "ack G 0 protocol using 8A0 trainer kit and ViRtSim.

Theory:

%n o "ack G 0 protocol if one frame is damaged or lost& all frames send since the lost

frame acknowledged is retransmitted. The recei!er sends an acknowledge frame for a group of

data frames. 1nly one acknowledgement is enough for a group of transmitted data. %n case of lost

data frames the transmitter sends a negati!e acknowledgement with data frame that is damagedor lost. 1nce the sender recei!es a 0AH& it retransmits the data. %f there is a repetition the

recei!er discards one of the data.

Pro&ed)re:

Step -2 Connect the master/ser!er to the computer 0%C port.



Step =2 Reset the 0%C - and then the de!ice %D will read successfully.


Step @2 To load the


28/35

Step --2 connect the :C with the kit and send the data.

Step -*2 ?hile transmitting& enter the error "y pressing the error "utton on the 8A0 kit as

many times as the num"er of frames in data.

Step -+2 A 0A frame will "e transmitted to the sender and transmission will "e stopped.

Step -=2 The transmission is resumed when the data is again send.

Step ->2 1nce data reaches the destination stop the eecution.

*e!)t:

Thus the o "ack 3 0 protocol was implemented and simulated using V%38A0 trainer kit

and ViRtSim software.

Exp No: 11


29/35

Date:

St)dy o% Net#or$!im)ator -NS. a"d Sim)atio" o% Co"(e!tio"

Co"tro A(orithm! )!i"( NS

Aim :

To Study of 0etwork simulator #0S$ and Simulation of Congestion Control Algorithms using 0S.

Theory:

NET


30/35

likelihood of a "uffer o!erflow in a network& the time re'uired for an accurate answer can "eetremely large. Speciali,ed techni'ues such as Icontrol !ariatesI and Iimportance samplingIha!e "een de!eloped to speed simulation.

Exampe! o% "et#or$ !im)ator!

There are many "oth free/open3source and proprietary network simulators. amples of nota"le network simulation software are& ordered after how often they are mentioned in research papers2

-.ns #open source$

*.1:0T #proprietary software$+. 0etSim #proprietary software$

U!e! o% "et#or$ !im)ator!

0etwork simulators ser!e a !ariety of needs. Compared to the cost and time in!ol!ed in settingup an entire test "ed containing multiple networked computers& routers and data links& network simulators are relati!ely fast and inepensi!e. They allow engineers& researchers to test scenariosthat might "e particularly difficult or epensi!e to emulate using real hardware 3 for instance&simulating a scenario with se!eral nodes or eperimenting with a new protocol in the network. 0etwork simulators are particularly useful in allowing researchers to test new networking protocols or changes to eisting protocols in a controlled and reproduci"le en!ironment. Atypical network simulator encompasses a wide range of networking technologies and can helpthe users to "uild comple networks from "asic "uilding "locks such as a !ariety of nodes and

links. ?ith the help of simulators& one can design hierarchical networks using !arious types of nodes like computers& hu"s& "ridges& routers& switches& links& mo"ile units etc.

Various types of ?ide Area 0etwork #?A0$ technologies like TC:& ATM& %: etc. and 8ocal Area 0etwork #8A0$ technologies like thernet& token rings etc.& can all "e simulated with a typicalsimulator and the user can test& analy,e !arious standard results apart from de!ising some no!el protocol or strategy for routing etc. 0etwork simulators are also widely used to simulate "attlefield networks in 0etwork3centric warfare

There are a wide !ariety of network simulators& ranging from the !ery simple to the !erycomple. Minimally& a network simulator must ena"le a user to represent a topology& Specifying

the nodes on the network& the links "etween those nodes and the traffic "etween the nodes. Morecomplicated systems may allow the user to specify e!erything a"out the protocols used to handletraffic in a network. raphical applications allow users to easily !isuali,e the workings of their simulated en!ironment. Tet3"ased applications may pro!ide a less intuiti!e interface& "ut may permit more ad!anced forms of customi,ation.

http://en.wikipedia.org/wiki/Ns_(simulator)http://en.wikipedia.org/wiki/OPNEThttp://en.wikipedia.org/wiki/NetSimhttp://en.wikipedia.org/wiki/Test_bedhttp://en.wikipedia.org/wiki/Computerhttp://en.wikipedia.org/wiki/Computerhttp://en.wikipedia.org/wiki/Router_(computing)http://en.wikipedia.org/wiki/Data_linkhttp://en.wikipedia.org/wiki/Data_linkhttp://en.wikipedia.org/wiki/Emulatehttp://en.wikipedia.org/wiki/Emulatehttp://en.wikipedia.org/wiki/Network_hubhttp://en.wikipedia.org/wiki/Network_hubhttp://en.wikipedia.org/wiki/Network_bridgehttp://en.wikipedia.org/wiki/Network_bridgehttp://en.wikipedia.org/wiki/Wide_Area_Networkhttp://en.wikipedia.org/wiki/Local_Area_Networkhttp://en.wikipedia.org/wiki/Local_Area_Networkhttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Token_ringhttp://en.wikipedia.org/wiki/Network-centric_warfarehttp://en.wikipedia.org/wiki/Ns_(simulator)http://en.wikipedia.org/wiki/OPNEThttp://en.wikipedia.org/wiki/NetSimhttp://en.wikipedia.org/wiki/Test_bedhttp://en.wikipedia.org/wiki/Computerhttp://en.wikipedia.org/wiki/Router_(computing)http://en.wikipedia.org/wiki/Data_linkhttp://en.wikipedia.org/wiki/Emulatehttp://en.wikipedia.org/wiki/Network_hubhttp://en.wikipedia.org/wiki/Network_bridgehttp://en.wikipedia.org/wiki/Wide_Area_Networkhttp://en.wikipedia.org/wiki/Local_Area_Networkhttp://en.wikipedia.org/wiki/Local_Area_Networkhttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Token_ringhttp://en.wikipedia.org/wiki/Network-centric_warfarehttp://en.wikipedia.org/wiki/Network-centric_warfare


31/35

Pa&$et o!!

1ccurs when one or more packets of data tra!elling across a computer networkfail to reachtheir destination. :acket loss is distinguished as one of the three main error types encountered indigital communicationsK the other two "eing "it error and spurious packets caused due to noise.

:ackets can "e lost in a network "ecause they may "e dropped when a 'ueue in the network node

o!erflows. The amount of packet loss during the steady state is another important property of acongestion control scheme. The larger the !alue of packet loss& the more difficult it is for transport layer protocols to maintain high "andwidths& the sensiti!ity to loss of indi!idual packets& as well as to fre'uency and patterns of loss among longer packet se'uences is stronglydependent on the application itself.

Thro)(hp)t

This is the main performance measure characteristic& and most widely used. %n communicationnetworks& such as thernet or packet radio& throughput or network. Throughput is the a!eragerate of successful message deli!ery o!er a communication channel. The throughput is usually

measured in "its per second #"it/s or "ps$& and sometimes in data packets per second or data packets per time slot This measure how soon the recei!er is a"le to get a certain amount of datasend "y the sender. %t is determined as the ratio of the total data recei!ed to the end to end delay.Throughput is an important factor which directly impacts the network performance

Deay

Delay is the time elapsed while a packet tra!els from one point e.g.& source premise or network ingress to destination premise or network degrees. The larger the !alue of delay& the moredifficult it is for transport layer protocols to maintain high"and widths. ?e will calculate end toend delay

>)e)e Le"(th

A 'ueuing system in networks can "e descri"ed as packets arri!ing for ser!ice& waiting for ser!ice if it is not immediate& and if ha!ing waited for ser!ice& lea!ing the system after "eingser!ed. Thus 'ueue length is !ery important characteristic to determine that how well the acti!e'ueue management of the congestion control algorithm has "een working.

*ESULT:

Thus the study of 0etwork simulator #0S*$ was studied.


32/35

Exp No: 1+

Date:

St)dy o% So&$et Pro(rammi"( ? Cie"t Ser'er Mode

Aim:

To implement socket programming date and time display from client to ser!er using TC:Sockets

AL2O*IT@M:

Ser'er

-.Create a ser!er socket and "ind it to port.*.8isten for new connection and when a connection arri!es& accept it.

+.Send ser!er ‟s date and time to the client.

=.Read client‟s %: address sent "y the client.

>.Display the client details.

@.Repeat steps *3> until the ser!er is terminated.

.Close all streams.

(.Close the ser!er socket.

E.Stop.

Cie"t

-.Create a client socket and connect it to the ser!er ‟s port num"er.

*.Retrie!e its own %: address using "uilt3in function.

+.Send its address to the ser!er.

=.Display the date L time sent "y the ser!er.

>.Close the input and output streams.

@.Close the client socket.

. Stop.


33/35

P*O2*AM:

//TCP Date Ser'er77t&pdate!er'era'a

import 4a!a.io.K

import 4a!a.util.K

class tcpdateser!er

N

pu"lic static !oid main#String argOP$

N

Ser!erSocket ss Q nullK Socket csK :rintStream psK 5ufferedReader disK String inetK try

N

ss Q new Ser!erSocket#====$K System.out.println#I:ress CtrlC to 'uitI$K while#true$

N

cs Q ss.accept#$K

ps Q new :rintStream#cs.get1utputStream#$$K

Date d Q new Date#$

ps.println#d$K

dis Q new 5ufferedReader#new %nputStreamReader#cs.get%nputStream#$$$K inet Q dis.read8ine#$KSystem.out.println#IClient System/%: address is 2I inet$K ps.close#$K dis.close#$K

catch#%1ception e$

N System.out.println#IThe eception is 2I e$K

// TCP Date Cie"t77t&pdate&ie"ta'a

import 4a!a.net.K

import 4a!a.io.K class tcpdateclient

N

pu"lic static !oid main #String argsOP$ N Socket socK 5ufferedReader disK String sdateK:rintStream psK

try N %netAddress ia Q %netAddress.get8ocalost#$K if #args.length QQ )$

soc Q new Socket#%netAddress.get8ocalost#$&====$K


34/35

else soc Q new Socket#%netAddress.get5y0ame#argsO)P$&====$K

dis Q new 5ufferedReader#new %nputStreamReader#soc.get%nputStream#$$$K

sdateQdis.read8ine#$K System.out.println#IThe date/time on ser!er is 2 I sdate$K ps Q new

:rintStream#soc.get1utputStream#$$K

ps.println#ia$K

ps.close#$K catch#%1ception e$

N

System.out.println#IT C:T%10 is 2I e$K

*ESULT:

Thus the program for implementing to display date and time from client to ser!er usingTC: Sockets was eecuted successfully and output !erified using !arious samples.


35/35

OUTPUT :

U 4a!ac tcpdateser!er.4a!a U 4a!a tcpdateser!er :ress CtrlC to 'uit Client System/%: address is 2 localhost.localdomain/-*.).).-Client System/%: address is 2 localhost.localdomain/-*.).).-

4a!ac tcpdateclient.4a!a U 4a!a tcpdateclient The date/time on ser!er is2 ?ed ul )@)2-*2)+ MT *)--

!ery time when a client connects to the ser!er& ser!er ‟s date/time will "ereturned to the client for synchroni,ation.

Documents

Computer Networks lab maual