Ccn Lab Manual vtu

T.JOHN INSTITUTE OF TECHNOLOGY BANGALORE-83 DEPARTMENT OF TELECOMMUNICATION ENGINEERING.

CCN LAB MANUAL

Prepared By Mr.NARAY Mr.NAR AYANA ANA SWAMY.R Assoc.Prof, Dept of TCE TJIT, BANAL!RE

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C!NTENTS I. CCN Programming Experiments in C/C++ (3 lab sessions of 3 hrs each) 1. Simlate bit/character stffing ! "e#stffing sing $%&C '. Simlate the shortest path algorithm 3. Encrption an" "ecrption of a gien message *. in" minimm spanning tree of a sbnet ,. Compte polnomial co"e chec-sm for CC#CCI II. CCN Experiments Experiments sing $ar"0are (1 lab session of 3 $rs each) 1. snchronos an" Snchronos Commnication sing S '3'/ 2ptical iber/ 0iste" 0iste" pair / *, '. 4sing for- fnction creates 52 processes an" commnicates bet0een them. 3. Commnicate bet0een 52 PCs6 sing simple soc-et fnction. III. %emonstrate the operations of rlogin an" telnet I7. I7. %emonstrate the operations of ftp6 mailbox.









W"at #s DLL $Data L#%& Layer'

he %ata &in- &aer is the secon" laer in the 2SI mo"el6 aboe the Phsical &aer6 0hich ensres that the error free "ata is transferre" bet0een the a"8acent no"es in the net0or-. It brea-s the "atagrams passe" "o0n b aboe laers an" conerts them into frames rea" for transfer. his is calle" raming. It proi"es t0o main fnctionalities eliable "ata transfer serice bet0een t0o peer net0or- laers lo0 Control mechanism 0hich reglates the flo0 of frames sch that "ata congestion is not there at slo0 receiers "e to fast sen"ers.  

W"at #s fra(#%)*

Since the phsical laer merel accepts an" transmits a stream of bits 0ithot an regar" to meaning or strctre6 it is p to the "ata lin- laer to create an" recogni9e frame bon"aries. his can be accomplishe" b attaching special bit patterns to the beginning an" en" of the frame. If these bit patterns can acci"entall occr in "ata6 special care mst be ta-en to ma-e sre these patterns are not incorrectl interprete" as frame "elimiters. he for framing metho"s that are 0i"el se" are +. Character cont . Starting an" en"ing characters6 0ith character stffing -. Starting an" en"ing flags6 0ith bit stffing . Phsical laer co"ing iolations +.

C"ar C"arac acte terr Co/% Co/%tt his metho" ses a fiel" in the hea"er to specif the nmber of characters in the frame. 5hen the "ata lin- laer at the "estination sees the character cont6 it -no0s ho0 man characters follo06 an" hence 0here the en" of the frame is. he "isa"antage is that if the cont is garble" b a transmission error6 the "estination 0ill lose snchroni9ation an" 0ill be nable to locate the start of the next frame. So6 this metho" is rarel se".

.

C"ar C"arac acte terr st/f st/ff# f#%) %) In the secon" metho"6 each frame starts 0ith the SCII character se:ence %&E S; an" en"s 0ith the se:ence %&E E;.(0here %&E is %ata &in- Escape6 S; is Start of e;t an" E; is En" of e;t.) his meth metho" o" oer oerco come mess the the "ra0 "ra0ba bacc-ss of the the char charac acte terr con contt meth metho" o".. If the the "est "estin inat atio ion n eer eer lose losess snchroni9ation6 it onl has to loo- for %&E S; an" %&E E; characters. If ho0eer6 binar "ata is being transmitte" then there exists a possibilit of the characters %&E S; an" %&E E; occrring in the "ata. Since this can interfere 0ith the framing6 a techni:e calle" character stffing is se".

So0/t#o%1 4se characterstuffing < 0ithin the frame6 replace eer occrrence of %&E 0ith the t0o#character se:ence %&E %&E. he receier reerses the processes6 replacing eer occrrence of %&E %&E 0ith a single %&Ebefore this "ata is gien to the net0or- laer. laer.

E2a(p0e1 If the frame containe" == > %&E % E %&E??6 the characters transmitte" oer the channel 0ol"









D#sad3a%ta)e1 character is the smallest nit that can be operate" on< not all architectres are bte oriente" an" this is a ma8or hr"le in transmitting arbitrar si9e" characters.

-.

B#t st st/ff#%) he thir" metho" allo0s "ata frames to contain an arbitrar nmber of bits an" allo0s character co"es 0ith an arbitrar nmber of bits per character. >it stffing is se" for arios prposes6 sch as a.

4or 5r#%)#%) 5r#%)#%) 5#t strea( strea(ss t"at do %ot %ecessar# %ecessar#0y 0y "a3e t"e sa(e sa(e or rat#o%a0 rat#o%a00y 0y re0ated re0ated 5#t rates rates /p to a co(( co((o% o% rate rate6 or to fill fill bff bffer erss or fram frames es.. he he loca locati tion on of the the stf stffi fing ng bits bits is commnicate" to the receiing en" of the "ata lin-6 0here these extra bits are remoe" to retrn the bit streams to their original bit rates or form. >it stffing ma be se" to snchroni9e seeral channels before mltiplexing or to rate#match t0o single channels to each other.

pplications incl"e Plesiochronos %igital $ierarch an" Snchronos %igital $ierarch. $ierarch. 5.

A%ot"e A%ot"err /se of of 5#t st/ff#% st/ff#%) ) #s for r/% r/% 0e%)t" 0e%)t" 0#(#t 0#(#ted ed cod#%) cod#%)@ to limit the nmber of consectie bits of the same ale in the "ata to be transmitte".  bit of the opposite ale is inserte" after the maximm allo0e" nmber of consectie bits. Since this is a general rle the receier "oesn?t nee" extra information abot the location of the stffing bits in or"er to "o the "estffing. his is "one to create a""itional signal transitions to ensre reliable transmission or to escape special resere" co"e 0or"s sch as frame snc se:ences 0hen the "ata happens to contain them.

pplications incl"e Controller rea Net0or-6 $%&C6 an" 4niersal Serial >s. >it stffing "oes not ensre that the paloa" is intact (i.e. not corrpte" b transmission errors)< it is merel a 0a of attempting to ensre that the transmission starts an" en"s at the correct places. Error "etection an" correction techni:es are se" to chec- the frame for corrption after its "elier an"6 if necessar6 necessar6 the frame 0ill be resent. 6ero75#t #%sert#o%

Aero#bit insertion is a particlar tpe of bit stffing (in the latter sense) se" in some "ata transmission protocols. It 0as poplari9e" b I>B?s S%&C (later rename" $%&C)6 to ensre that the rame Snc Se:ence (SS) neer appears in a "ata frame. n SS is the metho" of frame snchroni9ation se" b $%&C to in"icate the beginning an"/or en" of a frame. he name relates to the insertion of onl  bits. No 1 bits are inserte" inserte" to limit se:ences of  bits. he bit se:ence D111111D containing six a"8acent 1 bits is commonl se" as a Dlag bteD or SS. o ensre that this pattern neer appears in normal "ata6 a  bit is stffe" after eer fie 1 bits in the "ata. his tpicall a""s 1 stffe" bit to eer 3' ran"om paloa" bits6 on aerage. Note that this stffe" bit is a""e" een if the follo0ing "ata bit is 6 0hich col" not be mista-en for a snc se:ence6 so that the receier can nambigosl "istingish stffe" bits from normal bits. 5hen the receier sees fie consectie 1s in the incoming "ata stream6 follo0e" b a 9ero bit6 it atomaticall "estffs the  bit. he bon"ar bet0een t0o frames can be "etermine" b locating the flag pattern. .

P"ys P"ys#c #ca0 a0 0aye 0ayerr cod# cod#%) %) 3#o0 3#o0at at#o #o%s %s

he final framing metho" is phsical laer co"ing iolations an" is applicable to net0or-s in 0hich the enco"ing on the phsical me"im contains some re"n"anc. In sch cases normall6 a 1 bit is a high#lo0 pair an" a  bit is i s a lo0#high pair. he combinations of lo0#lo0 an" high#high 0hich are not se" for "ata ma be se" for mar-ing frame bon"aries.









//************************************** // Name: bit stuffing // Description: performs performs bit stuffing/destuffing stuffing/destuffing on an input input data stream //************************************** #include #include #define MAX!" $%% int main&' ( char *p)*+ char temp+ char in,MAX!"-+ char stuff,MAX!"-+ char destuff,MAX!"-+ int count%+ printf&enter the input character string &%0s 1 $0s onl2':3n'+ scanf&4s)in'+ pin+ stuff+ 5hile&*p673%7' ( if&*p7%7' ( **p+ 88+ p88+ 9 else ( 5hile&*p7$7 11 count6' ( count88+ **p+ 88+ p88+ 9









count%+ 9 9 *73%7+ printf&3nthe stuffed character string is'+ printf&3n4s)stuff'+ pstuff+ destuff+

5hile&*p673%7' ( if&*p7%7' ( **p+ 88+ p88+ 9 else ( 5hile&*p7$7 11 count6' ( count88+ **p+ 88+ p88+ 9 if&count' ( p88+ 9 count%+ 9 9 *73%7+ printf&3nthe destuffed character string is'+ printf&3n4s3n)destuff'+ return %+ 9

enter the input character string &%0s 1 $0s onl2':

$$$$$ the stuffed character string is

$$$$%$ the destuffed character string is

$$$$$











//************************************** // Name: character character stuffing // Description:to perform perform character character stuffing on input input data stream&net5or;ing stream&net5or;ing // lin; la2er la2er actiit2' //**************************************

#include #include #define MAX!" $%% int main&' ( char in,MAX!"-)stuff,MAX!"-)d in,MAX!"-)stuff,MAX!"-)destuff,MAX!"-+ estuff,MAX!"-+ char *p)*+ int i+ printf&enter the string to be character stuffed3n'+ scanf&4s)in'+ pin+ stuff+ 5hile&*p673%7' ( if&*p7d7' ( **p+ p88+ 88+ if&*p7l7' ( **p+ p88+









9 *73%7+ printf&3nthe stuffed string is'+ printf&3n4s)stuff'+

pstuff+ destuff+

5hile&*p673%7' ( if&*p7d7' ( **p+ p88+ 88+ if&*p7l7' ( **p+ p88+ 88+ if&*p7e7' ( **p+ p88+ 88+ for&i$+i<=+i88' p88+ 9 9 9 else ( **p+ 88+ p88+ 9 9 *73%7+ printf&3nthe destuffed string is'+ printf&3n4s3n)destuff'+ return %+ 9









Data Encryt!"n an# D$cryt!"n plaintext ) into something that appears to be ran"om an" Encrption is the process of translating plain text "ata ( plaintext meaningless (cipher text). %ecrption is the process of conerting cipher text bac- to plaintext.

o encrpt encrpt more than a small amont of "ata6 symmetric encryption is se".  symmetric key is se" "ring both the encrption an" "ecrption processes. o "ecrpt a particlar piece of cipher text6 the -e that 0as se" to encrpt the "ata mst be se". he goal of eer encrption algorithm is to ma-e it as "ifficlt as possible to "ecrpt the generate" cipher text 0ithot sing the -e. If a reall goo" encrption algorithm is se"6 there is no techni:e significantl better than metho"icall tring eer possible -e. or sch an algorithm6 the longer the -e6 the more "ifficlt it is to "ecrpt a piece of cipher text 0ithot possessing the -e.

//************************************** // Name: ncr2ption and Decr2ption Decr2ption of string string //**************************************

#include









str[i]  str[i] " key; $ $ int %ain() int %ain() { char str[] char str[]  &s%urff'kdo& ; printf(&*ass+rod printf( &*ass+rod  s-n& s-n&,str); ,str); encrypt(str,!/'0'); printf(&1ncrypted printf( &1ncrypted value  s-n& ,str); decrypt(str,!/'0'); printf(&ecrypted printf( &ecrypted value  s-n& ,str); return !; return !; $

S"ortest pat" pro50e( In graph In graph theor6 the theor6 the s"ortest pat" pro50e( is the problem of fin"ing a path a path bet0een bet0een t0o ertices t0o ertices (or no"es) in a graph sch graph sch that the sm of the 0eights of 0eights of its constitent e"ges is minimi9e". he most important algorithms for soling this problem are@ •

D#8&stra9s a0)or#t"( soles the single#sorce shortest path problems.

•

>ellmanor" algorithm soles algorithm soles the single#sorce problem if e"ge 0eights ma be negatie.

•

F search algorithm soles algorithm soles for single pair shortest path sing heristics to tr to spee" p t he search.

•

lo"5arshall algorithm soles algorithm soles all pairs shortest paths.

•

ohnson?s algorithm soles algorithm soles all pairs shortest paths6 an" ma be faster than lo"5arshall lo"5arshall on sparse graphs. graphs.

""itional algorithms an" associate" ealations ma be fon" in Cher-ass- et al. al.G1H Def#%#t#o%









he he s#%)0e7so/rce s"ortest pat" pro50e(6 in 0hich 0e hae to fin" shortest paths from a sorce ertex v to all other ertices in the graph. s#%)0e7dest#%at# t#%at#o% o% s"ortest s"ortest pat" pro50e( pro50e(6 in 0hich 0e hae to fin" shortest paths from all he s#%)0e7des ertices in the "irecte" graph to a single "estination ertex v. his can be re"ce" to the single#sorce shortest path problem b reersing the arcs in the "irecte" graph. he a007pa#rs s"ortest pat" pro50e(6 in 0hich 0e hae to fin" shortest paths bet0een eer pair of ertices v6 v' in in the graph. hese generali9ations hae significantl more efficient algorithms than the simplistic approach of rnning a single#pair shortest path algorithm on all releant pairs of ertices. •

•

•

D!%&'tra(' A)*"r!t+, Dijkstra's algorithm is a greedy algorithm that solves the shortest path problem for a directed graph G.Dijkstra's algorithm solves the single-source shortest-path problem when all edges have non-negative weights.

Dijkstra's Algorithm 234567'(8, +, s) 9 2262':21528:15=701(8, s)  5 ?@ A B ?C[8] D+hile B E@ F do u ? 1G67'06H2(B) I 5 ? 5 {u$ J for each verte v 'dK[u] L do71:'G(u, v, +)











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// Name: shortest path path algorithm //**************************************

#include #include #include #include void %ain() void %ain() { int int path[F][F],i,K,%in,a[F][F],p,st9,edF,stp,edp,t[F],inde; clrscr(); printf(&enter printf(&enter the cost %atri-n& ); for(i9;i<F;i"") for (i9;i<F;i"") for(K9;K<F;K"") for (K9;K<F;K"") scanf(&d& scanf( &d&,Ma[i][K]); ,Ma[i][K]); printf(&enter printf(&enter nu%Ner of paths-n& ); scanf(&d& scanf( &d&,Mp); ,Mp); printf(&enter printf(&enter possiNle paths-n& ); for(i9;i<p;i"") for (i9;i<p;i"") for(K9;K<F;K"") for (K9;K<F;K"") scanf(&d& scanf( &d&,Mpath[i][K]); ,Mpath[i][K]);

for(i9;i<p;i"") for (i9;i<p;i"") { t[i]!; stpst; for(K9;K<F;K"") for(K9;K<F;K"") { edppath[i][K"9];









if(path[inde][i]ed) if(path[inde][i]ed) Nreak; Nreak ; $ getch(); $

OP=6*=6Q enter the cost %atri Q ! 9 D  ! ! ! !  A ! ! ! A ! ! ! ! ! F ! ! ! ! ! enter nu%Ner of paths Q D enter possiNle paths Q 9  D F ! 9  F ! ! 9 D F ! ! 9 A D F ! %ini%u% cost Q D %ini%u% cost path Q 9R>R>FPO











Pr#(9s A0)or#t"( A0)or#t"( Prim?s algorithm is a gree" algorithm that fin"s a minimm spanning tree for a connecte" 0eighte" n"irecte" graph. It fin"s a sbset of the e"ges that forms a tree that i ncl"es eer ertex6 0here the total 0eight of all the e"ges in the tree is minimi9e". his algorithm is "irectl base" on the BS (minimm spanning tree) propert.

E2a(p0e

 Simple 5eighte" raph

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C IMPLEMETATI!N of pr#(9s A0)or#t"( Vincl"eTst"io.hW Vincl"eTconio.hW inta6b666n6i686neU1< int isite"G1HUXY6min6mincostU6costG1H isite"G1HUXY6min6mincostU6costG1HG1H< G1H< oi" main() X clrscr()< printf(DZnEnter the nmber nmber of no"es@D)< scanf(D["D6!n)< printf(DZnEnter the a"8acenc a"8acenc matrix@ZnD)< for(iU1








his is a C Program for implementing CC (Cclic e"n"anc Chec- Co"e) /include 0stdio.h1 /include 0conio.h1 /include 0string.h1 voidmain23 4 inti5j5keylen5msglen6 charinput7&%%85key7*%85temp7*%859uot7&%%85rem7*%85key&7*%86 clrscr236 printf2:Enter Data; :36 gets2input36 printf2:Enter >3









for2i=%6i0keylen-&6i>>3 printf2:Bc:5rem7i836 printf2:@n(inal printf2:@n(inal data is; :36 for2i=%6i0msglen6i>>3 printf2:Bc:5input7i836 for2i=%6i0keylen-&6i>>3 printf2:Bc:5rem7i836 getch236 ?

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Ccn Lab Manual vtu

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