The document covers fundamental concepts related to computer networks, including various types such as personal, local, metropolitan, and wide area networks. It explains network protocols, focusing on the OSI and TCP/IP models, detailing their layers and functions. Additionally, the document discusses network architecture, error control, data transfer rules, and service types in networking.

1. පරිගණක ජා ලකරණය - මූලික සංකල්ප
විදුසරට මා ලියූ ලිපි පපළ
[2008 ඔක්තෝ බර් 15 – 2010 මැ යි 19]
පරිගණක වලින් වැ ඩගන්න ඉන්න දුවා පුතා ලා පවනුවනි!
තුති:
්මවන් ්ේ ඔබ ්වනුවන් ලියා පළ ්ෙරුමට උදව් ෙරපු හැ මට!
මූලිෙ සිේධා න්ත මා හට යළිත් මතක ්ෙරුවා වූ සියලුම මූලා ශ්‍රයන්ට!

2. 16
ú≥y,
2008 Tlaf;danr® 15
;dlaaIK wxYh
m˙.Kl cd,hkays jr®.SlrKh
m˙.Kl cd,hkays jr®.SlrKh
m˙.Kl cd,hkays jr®.SlrKh
m˙.Kl cd,hkays jr®.SlrKh
m˙.Kl cd,hkays jr®.SlrKh
(Classification of Computer Networks))
1. Personal Area Networks ^jr®.ógr® lsysmhla mqrdjg&
2. Local Area Network
^ldurhla" f.dvke.s,a,la" ldr®hd,hla" úYajúoHd,hla mqrdjg&
3. Metroplotitan Area Network ^k.rhla mqrdjg&
4. Wide Area Network ^rgla" wr®Ooaùmhla mqrdjg&
5. Internt ^mD:ßúh mqrdjg&
by;ska ≤lafjkafka Local Area Networks (LANs)
lsysmhla tl;= jk wjia:djla' th jkafka Routers lsysmhla
tlsfkl iïnkaO ùfuka'
m˙.Kl cd,hkays jvd;a ckm%sh u jr®.h Local Area
Netowrk (LAN) jr®.hhs' Tn ≤l we;s ldr®hd,j,"
úYajúoHd,j, tajf.a u úúO fomdr®;fïka;=" lr®udka;Yd,dj,
fujeks m˙.Kl cd, iq,n nj'
LAN jr®.fha cd,hla ilik wdldr (Topologies) lsysmhla
;sfnkjd' tajd kï"
BUS Topology
RING Topology
STAR Topology
W∞yrKh
W∞yrKh
W∞yrKh
W∞yrKh
W∞yrKh (i)
W∞yrKh
W∞yrKh
W∞yrKh
W∞yrKh
W∞yrKh (ii)
TREE Topology
MESH Topology
m˙.Kl cd,lrKfha jr®.SlrKh ms<sn|j ;j≥rg;a .eUq˙ka
l;d l< yelsuq;a fuu ,smsfhka ta ms<sn|j wjOdkh fhduq fkd
flfrk w;r ≤ka wms m˙.Kl cd,hkays o;a; .uka ls¯ug
Wmfhda.S jk kshuhka (PROTOCOLS) .ek b;d u ir,j
l;d lruq'
PROTOCOL - An agreement between the commu-
nication parties on how the communication must pro-
ceed. ^ikaksfõok mdr®Yajhka w;r ^hjkakd yd ,nd.kakd&
ikaksfõokh lrk wdldrh .ek we;s jk tlÛ;dj&
´kE u m˙.Kl cd,hla yryd o;a; .uka ls¯ug Protocol
tlla wksjdr®hfhka u wjYH fjkjd' uQ,sl jYfhka Protocol
jr®. 2ls'
1. ISO OST Protocool model
2. TCP/IP Protocl model
ISO OSI (Internationl Standard Organization - Open System Interconnection)
fuys m%Odk uÜgï (Layers) 7ls'
Layer 7 Application - Deales with users ^wmg weig fmfkk foh&
Layer 6 Presentation - Deales with format of data ^o;a; yd iïnkaO f,ahrh&
Layer 5 Session - Deals with the communication type ^ikaksfõok l%u .ek l;d lrhs&
Layer 4 Transport - Transport data ^o;a; iïfma%IKh&
Layer 3 Network - Deals with data packets ^o;a; melÜ .ek l;d lrhs&
Layer 2 Data Link - Deals with data frames ^o;a; rduq .ek l;d lrhs&
Layer 1 Physical - Deals with all physical equipment/Binary data ^1- 0 wdldrhg o;a; m˙jr®;kh
lr oDVdx. yryd wfkla m˙.Klhg hefjhs'&
TCP -IP (Transmission Control Protocal - Intern et protcol)
fuys m%Odk uÜgï (Layers ) 4ls'
Layer 4 Applicaton - Deals with users ^wmg fmfkk foh&
Layer 3 Transport - Provides a reliable service
Layer 2 Internet - Uses Intrent protocol
Layer 1 - Host to host
Network - Physical connection ^fN!;sl iïnkaOh&
jeo.;a -
jeo.;a -
jeo.;a -
jeo.;a -
jeo.;a - fï jr®. foflys ° u (OSI/TCP) hjkakd f.a ta ta uÜgï (senders Layers) ,nkakd f.a ta ta uÜgï yd l;d
lrhs'
fuu ,smsfhka wm l;d lf<a m˙.Kl cd, ms<sn| b;d u iqΩ fohls' tfy;a th ye¢kaùulg iEfya' wms miqj ;j≥rg;a ta .ek
úáka úg l;d lruq'
TCP (Transmission Control Protocol)
UDP (User Datagram Protocol)
;˙≥ ùrisxy

3. 18
ú≥y,
2008 Tlaf;danr® 22
;dlaaIK wxYh
miq.sh i;sfha wms TCP/IP iy ISO-OSI hk Protocol
fol ms<sn|j fláfhka l;d l< w;r" ^,smsfha wjidk w†hfr® †&
wo †k Tng jeo.;a fõ hehs is;k lreKq lsysmhla ^cd,lrKh
ms<sn|j& fuu ,smsh yryd f.k yer olajkakï'
TCP/ IP yd ISO-OSI jr®. foflys ° u wms Layers
Ndú; lruq' fuys °' fuu tla tla f,ahrh" l;d lrkafka ^tkï
ikaksfõokh lrkafka& ;ud f.a uÜgfï u isák f,ahrhka iuÛhs'
tkï hjkakd f.a (Sender's) m<uqjk f,ahrh ,nkakd f.a
(Receiver's) m<uqjk f,ahrh iuÛ;a" fojk f,ahrh" fojk
f,ahrh iuÛ;a" ta wdldrhg ms<sfj<ska ikaksfõokh lrhs' thg
wms Peer-to-peer communication hehs lshuq'
my; rE igyk th ;j≥rg;a meye†,s lrhs' th wms
cd,lrK wdlD;shla f,iska (Network architecture) y∫kajuq'
m˙.Kl cd,lrKh ms<sn| ≤kqu ,nk úg (Theoritical
knowledge in computer & data) tlS tla tla f,ahr
ms<sn|j b;d ixlSr®K f,i l;d lrkq ,efí' ta ta f,ahrhg w∞<
(TCP/IP yd ISO-OSI fudv, fofla u& ldr®hhka yd fiajdjka
we;s w;r wms fuys ° ta ms<sn| l;d lrkakg n,dfmdfrd;a;=
fkd fjuq' ^fuu ,sms fm<ska wm woyia lrkafka Tng cd,lrKfha
ixl,am ms<sn|j o< woyila ,nd °u mu◊&'
wm" by; ° wjOdkhg ,la lrkq ,enQ f,ahr (Layers)
ksr®udKfha ° ie,lsh hq;= lreKq my; olajñ' (Design issues
of layers).
1' m◊jqv yqjudrej ^o;a; iïfm%aIKh& i|yd wduka;%Kh
1' m◊jqv yqjudrej ^o;a; iïfm%aIKh& i|yd wduka;%Kh
1' m◊jqv yqjudrej ^o;a; iïfm%aIKh& i|yd wduka;%Kh
1' m◊jqv yqjudrej ^o;a; iïfm%aIKh& i|yd wduka;%Kh
1' m◊jqv yqjudrej ^o;a; iïfm%aIKh& i|yd wduka;%Kh
(Addressing)
ksYaÑ; b,lalhla y∫kd.ekSu fuys ° is≥ fõ'
(Specif y a speciic destination)
2' o;a; iïfm%AIK l%u
2' o;a; iïfm%AIK l%u
2' o;a; iïfm%AIK l%u
2' o;a; iïfm%AIK l%u
2' o;a; iïfm%AIK l%u (Rules of Data transfer)
tla w;lg muKla (Simplex) →
udr®. 2l fomig u (Full duplex) →
←
tla udr®.hl fomig u (half duplex) →←
3' f∞aI md,kh
3' f∞aI md,kh
3' f∞aI md,kh
3' f∞aI md,kh
3' f∞aI md,kh (Error control)
4' iïfma%IKh lrk o;a; melÜ
4' iïfma%IKh lrk o;a; melÜ
4' iïfma%IKh lrk o;a; melÜ
4' iïfma%IKh lrk o;a; melÜ
4' iïfma%IKh lrk o;a; melÜ (Data packets) l%ñlj
l%ñlj
l%ñlj
l%ñlj
l%ñlj
wxlkh ls¯u
wxlkh ls¯u
wxlkh ls¯u
wxlkh ls¯u
wxlkh ls¯u (Sequencing)
5' o;a; .,d hdu md,kh ls¯u
5' o;a; .,d hdu md,kh ls¯u
5' o;a; .,d hdu md,kh ls¯u
5' o;a; .,d hdu md,kh ls¯u
5' o;a; .,d hdu md,kh ls¯u (Flow control)
6' o;a;j, ^m◊jqvj,& †.
6' o;a;j, ^m◊jqvj,& †.
6' o;a;j, ^m◊jqvj,& †.
6' o;a;j, ^m◊jqvj,& †.
6' o;a;j, ^m◊jqvj,& †. (Message length)
7'
7'
7'
7'
7' Multiplexing/Demultiplexing
Mux - udr®. lsmhlska tk m◊jqv$o;a; tl udOHhla yryd
(Channel) heùu'
Demux - tl udr®.hlska tk o;a; udr®. lsysmhlska iudka;rj
iïfm%AIKh'
8' iïfm%AIK udr®. md,kh
8' iïfm%AIK udr®. md,kh
8' iïfm%AIK udr®. md,kh
8' iïfm%AIK udr®. md,kh
8' iïfm%AIK udr®. md,kh (Routing)
tla udr®.hla (Path) ldr®hnyq, (Busy) kï Routing
hk ixl,amh uÛska fjk udr®.hla (Alternating route
of destination) fidhd.efka'
W∞ (
→ 'Host 1' hk m˙.Klh Google server tlg iïnkaO
jk udr®.h olajhs'
→ 'Host 2' hk m˙.Klh Google server tlg iïnkaO
jk udr®.h olajhs'
b;ska Routing uÛska lrkafka" o;a; ^m◊jqv& .,d hdug
we;s udr®. ldr®hnyq, kï" fjk;a udr®.hlska wjidk bu olajd
o;a; heùuhs' ^fuu W∞yrKfha ° kï lv b˙j,ska jg lr we;s
udr®. 2 u ldr®hnyq, h&'
fyd|hs" ta wms l;d lf<a f,ahr (Layers) ksr®udKh ls¯fï
° ie,lsh hq;= lreKq h' fuu Layers uD≥ldx.uh ksr®udKhka
h' (Software implementation).
Layers ksr®udKh lr ;sfnkqfha o;a; yqjudrej myiq lr
.ekSu i|yd h' y˙hg wms wfma jev" l%ñlj (Step by step)
lrkjd jdf.a h'
f,ahrj, fiajd iemhqu yd ls%hdjka uQ,slj u wxY 4lg
fnfoa' (Service primitrives of layers).
1. Listen - o;a; tk foig wjOdkh fhduq ls¯u'
2. Connect - ;u peer f,ahrh iïnkaO ls¯u
^,nkakd f.a ;udj iudk f,ahrh&'
3. Send - o;a; heùu'
4. Disconnect - udr®.h úikaê ls¯u'
uq,slj u fiajd iemhqï jr®. 2ls'
1' fN!;sl iïnkaO;djla we;s fiajdj
(Connection oriented service)
2' fN!;sl iïnkaO;djla ke;s fiajdj
(Connection less service)
Connection oriented service)
ksYaÑ; udr®.hla we;' (Dedicatd data path).
tu udr®.h mhsmam nghla yd iudk h'
tkï"
fuys ° m%:ufhka u i,ld nef,kafka o;a; .,d hdfï
.=Kd;aulnjhs' (Quality of service first!)
r;= jr®Kfhka olajd we;af;a o;a; .,d hk ksYaÑ; udr®.hhs'
(Dedicated path)
iïnkaO;d iys; fiajdjka f;je±reï fjhs'
Connection orientrd services
Reliable Reliable Unreliable
message stream byte steram connection
^úYajikSh ^úYajdikSh ^wúYajikSh$
m◊jqv ∞uh& nhsÜ ∞uh& j.lSula ke;s
in|;dj&
Connection less services
• lsis≥ ksYaÑ; udr®.hla ke;' (No any dedicated
path)
• iEu o;a; meleÜgqjla u ;udg wNsu; m˙† f;dard
.kshs' (Each data packet has its own pat h)
o;a; melÜ flá u fyda ≥r u fyda udr®.h f;dard .kshs' ta
ms<sn| úYajdihla ke;' (Packets may take the SHORTEST
or L ONGESTpath).
• fuys ° cd,h yryd m◊jqv heùu t;rï .=Kd;aul ke;'
(Network is not efficient).
• fuys ° m%:ufhka u i,ld nef,kafka o;a; melÜ .,d
hdfï fõ.hhs' (Consider the SPEED of DATA first)
• fuu l%ufha ° Ndú; jk o;a; melÜ wms Datagram
^fâgd.%ï& f,iska y∫kajuq'
Datagram - a Packet of data which has no reliability
fuu fiajd úfYaIh o f;je±reï fjhs'
Connection less services
Unireliable Aknowldge Request-reply
datagram datagram
^úYajikSh;ajhla ^m◊jqv ,enqKd hehs ^b,aÆug iemhqu&
ke;s yÛjk
fâgd.%Eï Ndú;h& fâgd.%ï Ndú;h&
fyd|hs wms ta l;d lf<a f,ahr w;r m◊jqv$o;a; yqjudrefõ
° fhd∞.;a fiajdjka fojr®.h .ekhs'
≤ka wms ir,j l;d lruq' cd,hla yryd o;a; melÜ (Data
packets) .,d hk m%Odk wdldr fol ms<sn|j'
1' Circuit switching ^o;a; .uka ls¯ug fN!;sl
udr®.hla fjka jk&
2. Packet switching ^o;a; .uka ls¯ug ksYaÑ;
udr®.hla ke;s&
Circuit switching
• o;a; iïfm%AIKh i|yd ksYaÑ; udr®.hla we;' (There is
a dedicated path for data to flow)
• iEu o;a; meleÜgqjla u tl u uÛ .uka lrhs' (Each
data packet follows the same path)
• w;rueo Switch tlla fyda Router tlla ^iïnkaOl fyda
fhduqldrl& ì|jegqK fyd;a th o;a; .ukd.ukh iïmQr®Kfhka
u weKysgqjhs' (Switch/Router failure is FATAL)
• o;a; melÜ l%udkql+,j ,nkakdg <Ûd fú (Packets
arrives at the receiver in order)
• hjkakd iy ,nkakd w;r o;a; heùug fmr" in|;dj
;yjqre flfrhs' (There is a CALL SETUP between the
sender & receiver)
Packet switching
• o;a; iïfm%AIKh i|yd ksYaÑ; udr®.hla ke; (No
dededicated path)
• o;a; melÜ tl u u.l .uka fkd lrhs (Packets don't
follow the same path)
• w;rueo Switch tlla fyda Router tlla ì|jeàu
t;rï fkd n,mdhs' (Router/Switch failure are not fatal)
• o;a; melÜ l%ñlj ,nkakdg <Ûd fkd jqK;a w∞<
ia:dkhg flf,i fyda <Ûd fjhs'
m˙.Kl cd,lrKh
ms<sn|j ;j≥rg;a
Host 1 Host 2
Layer 5 Layer 5
Layer 4/5
interface
Layer 4/5
interface
Layer 4 Layer 4
Layer 3/4
interface
Layer 3 Layer 3
Layer 2/3
interface
Layer 2 Layer 2
Layer 1/2
interface
Layer 1 Layer 1
Layer 3/4
interface
Layer 2/3
interface
Layer 1/2
interface
PHYSICAL MEDIUM
A Network Architecture
Layer 5 protocol
Layer 4 protocol
Layer 3 protocol
Layer 2 protocol
Layer 1 protocol
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
MUX
De
MUX
Host 1
Host 2
Network (Internet)
udr®.h ldr®hnyq,hs
Google
server
→ →
data in data out
SubNet

4. 16
ú≥y,
2008 Tlaf;danr® 29
;dlaaIK wxYh
m˙.Kl cd,lrKh
wms bl=;a ,smsfhka wjOdkh fhduq lf<a" m˙.Kl cd,lrKfha
° fhfok f,ahr" fiajdjka iy o;a; .uka lrk wdldr .ekhs'
≤ka Tn fyd¢ka okakd" iuyr úg ks;r u Ndú; lrk
wka;r®cd,h (Internet) ms<sn|j wms fláfhka l;d lruq'
Internet - A vast collection of different networks that
use certain common protocols and provide certain com-
mon services. fláfhka u lshf;d;a" wka;r® cd,h hkq úúO
cd,hkays tl;=jlska iE≥Kq iqúYd,$ixlSr®K m˙.Kl cd,hls' tys
°" ;ekqï tall jk úúO ud†,sfha m˙.Kl cd," tl iudk
protcol yd services ^tlÛ;d iNd fiajd& Ndú; lrhs'
b;sydifhka'''
b;sydifhka'''
b;sydifhka'''
b;sydifhka'''
b;sydifhka'''
wka;r®cd,h ìys ùug uQ,slj u n,md we;af;a wefu˙ld
tlai;a ckmofha hqO Yla;sh$hqO Wml%u$fyia m◊jqv fiajd by<
oud.ekSfï wruqKhs' wms thg iS;, hqoaOhla (Cold war) hehs
lshuq' wka;r®cd,fha ;sô˙f.h jk Arpanet (Advanced Re-
search Projects Agency NET) ksr®udKh i|yd uQ,slj u
wjYH;dj u;= ù we;af;a wefu˙ld tlai;a ckmofha wdrCIl
wud;HxYhg h' 1950 oYlfha w.Nd.fha ° mekke.=Kq wjYH;dj
u; ^jvd fyd|" úYajikSh f;dr;=re yd ikaksfõok cd,hl
wjYH;dj - kHIaál hqoaOhl ° wdrCId ùug& 1960 ° muK
Paul Baran keue;af;la Distributed Switching Network
keue;s b;d úYajikSh ≥rl:k cd,hla ksr®udKh lf<a h' tfy;a"
th wefu˙ld tlai;a ckmofha AT&T keue;s n,j;a úoHd.drh
úiska m%;slafIam fl˙◊' ffojfha iroulg fuka ta m%;slafIam jqKq
ixl,amh Larry Roberts keue;a;l= úiska 1967 w.Nd.fha °
m%;sksr®udKh lrk ,oafoa Paul Baran f.a ksr®udKYS,s;ajh
f,djg lshdmdñks' b;ska" Larry Roberts m%;sksr®udKh l< tu
cd,lrK ixl,amh miqj ARPANET f,i ìys úh'
m%:u
m%:u
m%:u
m%:u
m%:u ARPANET ieliqu
ieliqu
ieliqu
ieliqu
m%:u
m%:u
m%:u
m%:u
m%:u ARPANET ksr®udK ieliqu
ksr®udK ieliqu
ksr®udK ieliqu
ksr®udK ieliqu
ksr®udK ieliqu
Original ARPANET Design
by; ≤lafjk m˙† m%:u ARPANET ksr®udK ieliqu" l=vd
m˙.Klj,ska (Mini computers) iukaú; fjhs' tajd wms
IMPs f,i y∫kajuq' (IMP - Interface Message Processors)
tajd 56kbps fõ.h we;s iïnkaOl uÛska iïnkaO ù we;'
56kbps hkq 56 kilobits per second ^;;amrhg lsf,daìÜ 56la
.,d hhs&' tl IMP tlla wvq u ;rfï ;j IMP 2lg j;a
iïnkaO fjhs' fuys ° Ndú;hg .efkkqfha Packet switching
l%uhhs' ukao túg w;rueo iïnkaO fyda IMP tlla fyda ì|
jeà ;snqfKd;a m◊jqv .,d hdug ndOdjla fkd jk ksid h' ì|
jegqK;a" o;a; melÜ úl,am udr®.j,ska ,nkakd fj; .uka lrhs'
(Pckets may take alternative paths in an IMP or
transmision line failure)
wms ta l;d lf<a wka;r®cd,fha ;sô˙f.h jk ARPANET
iïnkaOjhs'
ál l,la .; jk úg ARPANET iuÛ w;sfr®l cd,
moaO;Ska (LANs) tl;= jqKd' b;ska" cd,lrKh ixlSr®Kj;a u
ARPANET i|yd TCP/IP protocol tl iïnkaO flreKd' ta"
cd,lrKh ir, yd myiq lr .ekSug' flfia fyda 1980 jk úg
ARPANETys m˙udj jeä jqKd' túg ;u cd,fha we;s m˙.Kl
(Hosts) fidhd.ekSu ;rula ≥Ialr jQjd' b;ska Bg ms<shula
f,iska DNS (Domain Name Service) ixl,amh ksr®udKh
jQKd'
DNS → Organizes machines into domains and maps
host names onto IP (Internet protcol) addreses ^DNS
m˙.Kl" tla tla l=,lj,g iïnkaO lrk w;r u hostj,
kduhka IP ,smskhkag iïnkaO lrhs&
IP Address m˙.Klhla" wka;r®cd,fha fyda fjk;a cd,hl
fyda ia:ßrj we;súg" y∫kd.kakd ,smskh''''
IP ,smskhka jr®." Tng fmkajd fohs' my; rEm igyk (IP
Address formats)
IP Addresses m%Odk jr®. (clases) 4lg fnfoa' (Class A,
B C iy D hkqfjka&' fuu ,smsk uÛska m˙.Kl ñ,shk 16
ne.ska we;s cd, 128la fyda m˙.Kl 64000la we;s cd, 16384la
fyda m˙.Kl 256la we;s cd, ñ,shk 2la fyda wduka;%Kh l<
yels h'
IMP IMP
Subnet
Host to Host protocol
Source IMP to Destination IMP
Protocol
IMP-IMP Protocol IMP-IMP Protocol
Host to
IMP protocol
IMP - Interface Message Processors
fyd|hs" kej;;a wka;r®cd,fha b;sydih .ek u;la lruq'
1980 jk úg ARPANETys m˙udj jeä jqK nj wms l,ska
i|yka l<d' ta ld,h jk úg úYajúoHd, iuyrl mr®fhaIK
lghq;= yd úúO jHdmD;sj,g (Research & developments)
ARPANET fnfyúka ∞hl jqKd' úoHd{hskag wefu˙ld tlai;a
ckmoh mqrdjg ;u o;a; yd f;dr;=re iïnkaO lr.; yels
jqKd' tfy;a úYajúoHd, ARPANET Ndú; lrkjd kï w't'
ckmofha wdrCIl wud;HxYh iuÛ mr®fhaIK .súiqula w;aika
l< hq;= j ;sfnkjd' ta;a fndfyda úYajúoHd, th is≥ lf<a keye'
Bg ms<shula jYfhka" trg úoHd moku (National Science
Foundation-NSF) ARPANETg iu.dój ta wdldrfha u
m˙.Kl cd,hla ksr®udKh l<d' thg m%Odk fya;=j jqfKa
úYajúoHd, mr®fhaIK uÜgï (Research levels) by< ≤óuhs'
fuys ° NSF uÛska we;s l< tu cd,h NSFNET kñka m%p,s;
jqKd' tys ° we't' ckmofha k.r 6l (San diego, Boulder
,
Champaign, Pittsburgh, Ithaca, Princeton) m%Odk" m%n,
m˙.Kl 6la uÛska fulS cd,h (Backbone network) iïnkaO
jqKd' wms tajd Super computer centers kñka y∫kajkjd'
my; ≤lafjkafka NSFNETys wdlD;shhs' ^1998 jr®Ih jk
úg& iEu Super computer tllg u iydhlhl= ^;j;a
m˙.Klhla& ,enqKd' t LSI 11 jr®.fha l=vd m˙.Klhla
(Mini computer). tu l=vd m˙.Kl Fuzz ball kñka o
ye¢kajqKd' fuu Fuzz balls, 56kbps fõ.h we;s flan,a uÛska
iïnkaO jqKd' (Fuzz balls 6 u&' fuu Fuzz balls
iïnkaO;dj TCP/IP uÛska" th f,dj m%:u TCP/IP cd,hhs'
(Wide Area Networks tlls&' th subnet tlls'
NSFNET yd ARPNANET
iïnkaO jqfKa' IMP tlla yd fuzz
ball tlla w;r we;s iïnkaO;djlsska'
fuu fuzz ball tl (Mini computer
tlla& msysgd ;snqfKa" Carnegie-
Mellon ^ldk.S fu,ka iriúfha&
m˙.Kl úoHd.drfha'
≤ka" wmg is;kakg mqΩjka"
ARPANET tflys m%:u m˙Kduh
NSFNET nj' 1990 jr®Ifha w.Nd.h
jk úg wfkla rgjÆ;a ^we't'
ckmohg wu;rj& fujeks ixlSr®K
cd,hka we;s lr .;a;d' tajdg wdor®Y
jqfKa ARPANET yd NSFNET
;dCIKhhs' tjeks cd,j,g W∞yrK
f,i hqfrdamfha EuropaNET iy
EBONE ye¢kaúh yelshs' uq,a ld,fha
fïjdfha o;a; .,d hdfï fõ.h 2Mbps jQ w;r miqj 34Mbps
olajd jeä jqKd'
miqj fujka iqúYd, cd," tlsfklg iïnkaO jqKd' wefu˙ld
tlai;a ckmofha" lekvdfõ" hqfrdamfha" meis*sla l,dmfha cd,hka
fuf,i iyiïnkaO jqKd' fuf,i" iqúYd, cd, .Kkdjla tl;=
ù wka;r®cd,h ksr®udKh jqKd' ≤kg f,dalfha" wka;r®cd,h yd
iïnkaO m%Odk m˙.Kl (Main frame computers) 13la
;sfnkjd' tu m˙.Kl wms Root servers f,i y∫kajkjd' fuu
m˙.Kl 13 msysgd we;af;a uqΩ mD:ßúh u wdjrKh jk m˙†'
my; ≤lafjkafka wka;r®cd,fha ir, wdlD;shla'
fyd|hs ys;j;=ks" wms wka;r®cd,fha (Internt) Wm; tys
wdlD;sh ms<sn|j b;d u ir,j l;d l<d' wms ,nk i;sfha
l;d lrkakg n,dfmdfrd;a;= jkafka" Tng jeo.;a hehs isf;k
World Wide Web ixl,amh ms<snjhs' Tng Internet mdúÉÑ
lrkakg ,efnkafka World Wide Web ksihs'
;˙∫ ùrisxy
POP - Point Of Presence
ISP - Internet Servie Provider
LAN - Local Area Network
NAP - Network Access Point
ARPANET design)
ieliu
q (Original

5. 16
ú≥y,
2008 fkdjeïnr® 26
;dlaaIK wxYh
jr®;udkfha" ikaksfõokfha m%Odk;u yd myiq u
ikaksfõok l%uhla f,i úoHq;a ;emE, (Electronic mail)
ye¢kaúh yels h' fuu ,smsh lshjk Tng;a úoHq;a
,smskhla we;ehs ug isf;a' jr®;udk ;reK mrmqr t;rï
u úoHq;a ;emE, yd iïnkaO h'
E-mail hk flá fh≥fuka ye¢kafjk úoHq;a ;emE," wo
f,dalfha rdcH uÜgñka" jHdmd˙l uÜgñka wdh;skl
uÜgñka ks, m◊jqv hjkakg mjd úoHq;a ,smskhla Ndú;
flfrhs' ta jf.a u fkdñ,fha úoHq;a ;eme,a fiajdjka ,nd
fok ( Free e-mail accounts) ckm%sh wdh;k ;sfnk nj
Tn okakjd we;ehs is;ñ' Tn tjka úoHq;a ;emE,la Ndú;
lrkjd fjkak;a mqΩjka' Google (gmail, Yahoo (yahoo
mail) tjka ckm%sh wdh;k folls'
Tng yqre mqre≥ úoHq;a ,smskh abc@gmail.com fydaaa
abc@yahoo.com fyda f,i wmg fmd≥ jYfhka ye¢kaúh
yels h' tfy;a tys idOdrK ksrEmKh username@dns-
name f,i y∫kajuq' 'dns-name' hkq w∞< domain tflys
kduhhs'
W∞ () gmail.com hkak wmg" commercial domain tflys
gmail subdomain tl f,i úÉf–okh l< yels h'
Tn fyd¢ka okakd Google, Yahoo, Hotmail jeks úoHq;a
;eme,a fiajd ,nd fok wdh;k Tng imhkafka Web mail
myiqluhs' tkï" tu wdh;kj, fjí wvú úiska Tng
iemfhk úoHq;a ;emE, (Free web mail accounts) wms gmail,
yahoo mail fyda hot mail f,i Ndú; lruq'
Tn f.a úoHq;a ;emE,g w∞< ,sms f.dkqfõ (mail box)
wdor®Ykhla my; ≤lafõ'
E-mail lshùu
lshùu
lshùu
lshùu
lshùu (Reading an e-mail)
idudkHfhka Tn Tfí e-mail account tlg we;=Ω jk
úg (log in) Tn f.a e-mail fiajd∞hlhd (e-mail agent) m<uqj
lrkafka Tng w¨f;ka e-mail tkjd ≤hs lshd h' miqj th
ta w¨f;ka meñ◊ e-mail Tng or®Ykh lrhs' wk;=rej
th" Tn f.ka úOdkhla (command) ,efnk ;=re n,d
isáhs'
by; j.=fjka Tng †ia jkafka idudkH e-mail account
tll mail box tfla iajNdjhhs'
ir, úoHq;a ;eme,a fiajdjl (simple e-mail system) by;
i|yka fields (# flags, bytes, sender, subject) tys ia:ßrj u
.nvd ù we;' (built in to the system). tfy;a ixlSr®K yd
kùk úoHq;a ;eme,a fiajdjl (complex & sophisticated e
mail system) fields, mdúÉÑ lrkakdg (user) wjYH m˙†
ilid .; yels h' th lrkafka ;uka f.a o;a; we;=<;a
fldgila (user profile) b†˙m;a ls¯fuks' (e-mail tfla display
format tl ^or®Ykh jk wdldrh& úia;r lrk file tlla&'
1. First field - message number ^úoHq;a ,smsfha wxlh&
2. Second field - message status ^,smsh lsfhõjd o"
ms<s;=re heõjd o" ;j;a flkl=g heõjd o hk j.&
K - already read
A - answered
F - forwarded
KA - read and answered
3. Third field - den scribes the length of the message
^,smsfha m%udKh Byte .Kkska&
4. Fourth field - sender ^,smsh tjQ ;eke;a;d&
5. Fifth field - subject ^,smsfha ud;Dldj&
úoHq;a ,smshla heùu
úoHq;a ,smshla heùu
úoHq;a ,smshla heùu
úoHq;a ,smshla heùu
úoHq;a ,smshla heùu (Sending an e-mail)
úoHq;a ,smshla heùu i|yd iemhsh hq;=$ ;sìh hq;= foa()
m◊jvqh (message)
,nkakd f.a e-mail ,smskh
(destination address)
m◊jqvh Free-standing text editor tll type l< yels
h' tfy;a fndfyda fiajd∞hlhka (e-mail agnets) m◊jvqh
type lrkakg' úfYaIs; text editor tlla Tjqka f.a fiajdjg
we;=<;a lr ;sfí' W∞ () gmail , yahoo jeks fiajd∞hlhka"
Tn f.a e-mail account tlg iïnkaO text editor tlla
imhd ;sfí&'
,nkakd f.a ,smskh receiver-name@dns-address
wdlD;shg wkqj ,nd †h hq;=hs'
Wod (- tharindu@ce.pdn.ac.lk
,nkakd f.a ku$
wkajr®: kduh dns-address
^l=ula fyda kula&
tfy;a ,nkakd f.a ,smskh i|yka lrk
;j;a wdlD;s ;sfí' tajd wm jeämqr Ndú;
lrkafka ke;' wms tajdf.a l%uhlg lshkafka
x.400 l%uh lsh,d' tu ^,smskh i|yka lrk&
l%uh Ndú; lrkafka" Tn ,nkakd f.a úoHq;a
,smskh ksje/†j u okafka ke;s úghs' tfy;a
Tn ,nkakd f.a hï f;dr;=rla ^/lshdj" /
lshdj lrk ia:dkh& ≤k isáh hq;=hs' tjka
,smskh;a ,shQ wdldrh my; ≤lafjkjd'
/ C = U S / S T = M A S S A C H U S E T T S /
L=CAMBRIDGE/PA=360 MEMORIAL DR./CN=STEVEN
SMITH
by; ,smskh" rgla (C=country)" m%dka;hla (S=state)"
†ia;s%lalhla (L=locality)" fm!oa.,sl ,smskh (PA=personal
address)" fmd≥ ku (CN=common name)
úia;r lrkjd' tfy;a fuu l%uh DNS-Addressing
l%uhg ^l,ska i|yka l<d& jvd myiq keye'
Mailing Lists ^úoHq;a ,sms f.dkq&
^úoHq;a ,sms f.dkq&
^úoHq;a ,sms f.dkq&
^úoHq;a ,sms f.dkq&
^úoHq;a ,sms f.dkq&
fndfyda e-mail fiajdjka mailing lists i|yd wjia:dj
,nd fohs' Tng ^tl u& m◊jqv" mqoa.,hka lsysm fokl=g
ksr;=rej jdf.a heúh hq;= kï" Tng ta ,nkakd f.a ,smsk
tl u l=,lhlg ^f.dkqjlg& we;=<;a l< yelshs' miqj
Tn ta l=,lhg m◊jqvh hejQ úg" th w∞< ,nkakkag
m◊jqvh fn∞ y˙hs' Mailing list tl we;af;a Tfí m˙.Klfha
kï (Locally maintained) Tn f.a e-mail agent ta list tfla
isák iEu whl=g u m◊jqvh fn∞ y˙hs' Mailing list
we;af;a fjk;a m˙.Klhl /Server tll kï (remotely
maintained) m◊jqvh fn∞ yefrkafka w∞< ia:dkfhks'
Tn m◊jqvh heúh hq;af;a w∞< server tlg h'
W∞ () wms ys;uq úYajúoHd,hl tla fomdr®;fïka;=jl
(department) wdpdr®hjreka f.a mailing list tlla
ce.pdn.ac.lk hk dns-address tl hgf;a .nvd ù we;ehs
lshd' tys ku 'lecturers' hehs is;uq' ≤ka" Tng ta
fomdr®;fïka;=fõ isák iEu wdpdr®hjrhl=g u fmd≥
m◊jqvhla heúh hq;= kï" lecturers@ce.pdn.ac.lk hk
,smskhg" §tla¶ m◊jqvhla heúh yels h' túg ce.pdn.ac.lkys
we;s mail server tl yryd w∞< ish¨ u wdpdr®hjrekag
(lecturers. hk list tfla wvx.=& m◊jqvh hefjhs'
# Flags Bytes Sender Subject
1 K 1030 Darshana Tomorrow's meeting
2 KA 6348 Thilina I am not coming
3 KF 4519 Peshila Re: Hi
4 K 1236 Nadeeka Bio chemistry
5 F 104110 Pubudu Watch me on TV
6 KAF 1223 Mohommad Re: How are you
Message formats ^m◊jvqj, wdlD;s&
^m◊jvqj, wdlD;s&
^m◊jvqj, wdlD;s&
^m◊jvqj, wdlD;s&
^m◊jvqj, wdlD;s&
wms ≤ka e-mail message formats ^úoHq;a ,smskhl m◊jqv
wdlD;ska& .ek ;rula l;d lruq'
uq,ska u wms m%d:ñl wjêfha wdlD;sh .ek wjOdkh
fhduq lruq' th ASCII e-mail l%uhg w∞< wdlD;shhs'
1. RFC 822
fuu wdlD;sh hgf;a úoHq;a ,smskhla hï fCIa;%
.Kklska (Header fields), ysia brlska (blank line) yd
m◊jqvhlska (message body) iukaú; h' my; j.=j
Tng th ukdj fmkajd fohs'
2. MIME - Multipurpose Internet Mail Extensions
ARPANET hq.fha úoHq;a ;eme,a l%uh" bx.S%isfhka ,shk
m◊jqv iuÛ h ne¨fKa' bx.S%isfhka ,shk ta m◊jqv
ASCII l%uhg yerfjkjd' tfy;a miqld,Skj fuh m%Yakhla
jqfKa" bx.S%ishg wu;rj fjk;a NdIdjka o email l%uhg
we;=<;a jQ ksidhs' ta jf.a u tl, Ndú; jQ RFC 822
wdlD;sfhka y~ yd rEm we;=<;a m◊jqv (Messages
containing audio of images) heùug;a m%Yakhla jqKd' Bg
ms<shula f,i MIME wdlD;sh ìys jqKd' MIME wdlD;sh
iïmQr®Kfhka u RFC 822 wdlD;sh Ndú; l< w;r wu;rj
ASCII fkd jk (non ASCII) m◊jqv i|yd ¯;s moaO;shla
(encoding nilles) f.dvke.=jd' l,ska RFC 822ys wvx.= jQ
Headersj,g wu;rj w¨;a Headers 5la MIME we;=<;a
l<d' ta my; i|yka tajd'
Header Meaning
To: E-mail address(es) of primary recipient(s)
Cc: E-mail address(es) of secondary recipient(s)
Bcc: E-mail address(es) for blind carbon copies
From: Person or people who created the message
Sender: E-mail address of the actual sender
Received: Line added by each transfer agent along the route
Return-path: Can be used to identify a path back to the sender
Header Meaning
MIME -version identifies the MIME version
Content Description Human-readable string telling
what is in the message
Content -ld: Unique identifier
Content- Transfer- How the body is wrapped for
transmission
Contetn Type Type and format of the content
^u;= iïnkaOhs&
^u;= iïnkaOhs&
^u;= iïnkaOhs&
^u;= iïnkaOhs&
^u;= iïnkaOhs&
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
E-mail

6. 16
ú≥y,
2008 foieïnr® 3
;dlaaIK wxYh
E-mail
Message Transfer (úoHq;a ;Eme,a m◊jqv yqjudrej&
úoHq;a ;Eme,a m◊jqv yqjudrej&
úoHq;a ;Eme,a m◊jqv yqjudrej&
úoHq;a ;Eme,a m◊jqv yqjudrej&
úoHq;a ;Eme,a m◊jqv yqjudrej&
úoHq;a ;eme,a yqjudrej hjkakd isg ,nkakd olajd
m◊jqvh .,d hdfï moaO;sh .ek l;d lrhs' ir, u
l%uh kï" fofokd w;r Transport connection tlla we;s
lr hjkakd isg ,nkakd olajd m◊jvqh yqjudre ls¯uhs'
ta i|yd fjka jqKq úúO ¯;s moaO;Ska (P rotocols)lsysmhla
;sfnkjd'
SMTP (Simple Mail Transfer protocol)
wka;r®cd,h ;=< e-mail m◊jqv hefjkafka" hjkakd
(Source machine) ,nkakd f.a Port 25g iïnkaO ù TCP
iïnkaO;dj;a id∞ .ekSfuks' Port 25 hkq ,nkakd
(Destination machine) wid isák port tlls' (Listening
port) . 'Port' tlla hkq uD≥ldx.uh ljqΩjla n∫ h' th
o;a; yqjudrej i|yd u fjka jqK újrhls' Port mdúÉÑ
lrkafka e-mail i|yd muKla fkd fõ' ´kE u o;a;
yqjudrejlg Port tlla Ndú; fjhs' Ports wxl ,nd
fokafka w∞< fufyhqï moaO;sh yryd h' (Operating system).
b;ska" Port 25 yryd lka °f.k isákafka SMPT NdIdj
l;d lrk e-mail domain flfkls' ^e-mail fiajd∞hlfhls&'
SMTP hkq ir, ASCII Protocol tlls' ^Protocol .ek
wms óg by; ° ixCIsma;j l;d l< ksid tys wr®:h
meye†,s lrkakg woyia fkd lrñ'& ASCII hkq American
Standard Code for Information Interchangeys flá fh≥uhs'
iEu ASCII wl=rla u (ASCII character) bit 7lska iukaú;hs'
ASCII fydaäfha wl=re 128la ;sfnkjd' fyd|hs wms SMTPys
ls%hdld˙;ajh .ek l;d lruq'
Sender yd Receiver ^hjkakd yd ,nkakd& w;r TCP
connection tl (port 25 yryd& we;s jQ miq sender, clinet
yeáhg n,d isákjd Receiver, server yeáhg ls%hd;aul
jk ;=re l;d lrkakg'''
wk;=rej Receiver (server tl f,i rÛmdkakd& ;ud
f.a wkkH;dj Tmamq lrñka text line tlla senderg hjkjd'
ta iuÛ u Tyq lshkjd Sender f.a m◊jqvh ,nd.ekSug
iQ∞kï lshd' tfia text line tlla ,enqfKa ke;akï" sender,
in|;dj uq∞ yer h<s;a j;djla W;aidy lrkjd'''
Server tl f,i rÛmdk Receiver tl iQ∞kï kï
Sender f.a m◊jqvh ,nd.kakg" Sender okajd isákjd'
Receiverg ldf.a úoHq;a ,smsh o (e- mail) tjkafka" ldg o
tjkafka lshd'''
tfia .e,fmk ,nkafkla isákjd kï Server tl
Clientg m◊jqvh heùug wjia:dj fokjd' tfia m◊jqvh
,enqKq miq Server tl th ,enqKd lshd h<s Clientg
wjOdrKh lrkjd' (Acknoweldging).
e - mail tl hjd wjika jQ miq Connection tl
w;yefrkjd'
thhs SMTPys ir, ls%hdld˙;ajh
2'
2'
2'
2'
2' POP3 (Post Office Protocol Version 3)
Internet service provider (ISP) fyda message transfer
agent ^m◊jqv yqjudre lrkakd& f.ka e-mail wmg
,efnkafka fldfydu o@ ta i|yd ksuejqKq protocol tlls
POP3. my; rEmh n,kak'
POP3 wdrïN jkafka Tn fyda uu fyda e-mail lshjkakg
e-mail reader ^fiajd∞hlhd f.a fiajdj& yd iïnkaO jk
fudfydf;ahs' Email reader tl wka;r®cd, fiajd imhkakd
(ISP) iuÛ TCP iïnkaO;djla y∞.kshs' ta Message
transfer agent iuÛ port 110 yryd h' Connection tl
ye≥Kdg miq POP3 my; wjia:d miq lrhs'
1' Authorization ^wkkH;dj ;yjqre ls˙u&
2' Transaction ^m◊jqv$o;a; yqjudrej&
3' Update ^w¨;a lr .ekSu&
3'
3'
3'
3'
3' IMAP (Internet Message Access Protocol)
RFC 2060ys wr®: olajd we;s ¯;s moaO;shls' IMAP tl
is;kjd iEu e-mail tlla u Server tfla úúO
mailboxesj, we;ehs lshd' b;d fiñka ls%hd;aul jk
MODEM tlla yryd e-mail in|;djla wm /f.k ;sfí
kï" IMAP b;d fyd¢ka wmg e-mail lshjkakg wjia:dj
,nd fokjd'''
IMAP wmg Multiple mailboxes ^nyqúO ;eme,a fmÜá&
ksr®udKh lrkakg" bj;a lrkakg wjia:dj ,nd fokjd'
ta wkqj wmg ´kE ;rï Mail boxes id∞.; yelshs wmg
e-mail tjkakka wkqj''
IMAP yd POP3 w;r fjkialï ≤lafjk my; j.=j
Tng ;j;a lreKq my∞ foaú'
moaO;s ;=< Ndú; jQfha úúO ;dCI◊l l%fudamdhka'
W∞yrKhla jYfhka ITU ixúOdkh ìys jQ wjêfha fndfyda
rgj,a Ndú; lf<a Morse Code ixl,amh jqj;a iuyr
rgj,a fjk;a fldaâ l%uhla Ndú; l<d'
ITUys m%Odk fldgia 3ls'
ITU
Development fector (ITU-D)^mr®fhaIK wxYh&
Radio Communications sector (ITU-R)
^.=jka ú≥,s ikaksfõokh ms<sn| wxYh&
Teleccmmunication Standardization sector (ITU-T)
^ú≥,s ixfoaY ;;a;ajlrK wxYh&
ITU-T fldgia 4lska iukaú; h' tkï jr®. 4l
idud‚lhka ms˙il f.ka th iukaú;hs' ta jr®. 4 kï
1' National governments
2' Sector members
3' Associate members
4' Regulatory agencies
fyd|hs" wms ta ir,j l;d lf<a e-mail ixl,amh
ms<sn|jhs'
cd, ;;a;ajlrKh
cd, ;;a;ajlrKh
cd, ;;a;ajlrKh
cd, ;;a;ajlrKh
cd, ;;a;ajlrKh
(Network Standardization)
wm t†fk∞ „ú;fha mdúÉÑ lrk fndfyda foaj,a hï
;;a;ajhlrKhla hgf;a ksis ;;a;ajlrKhlg Ndckh
ù we;a≤hs wms úuis,su;a jkafkuq' ksYaÑ; ;;a;aj iy;slhla
fkdue;s NdKavhla fyda øjHhla ñ, ° .ekSug wm ue,s
jkafka jr®;udkh jk úg ;;a;ajlrKh ta ;rug ckm%sh
ù we;s neúks'
fï jk f;la ud b†˙m;a l< ,sms flakaø.; jQfha
m˙.Kl cd,lrKh fj;hs' fï m˙.Kl cd,lrKhg;a
;;a;aj iy;sl ,nd °ula (Network standardization) is≥
fjkjd' wo uq,ska u ta .ek flá ye¢kaùula lrkakï'
ú≥,s ikafoaY f,dfjys m%n,;u ikaOdkh
ú≥,s ikafoaY f,dfjys m%n,;u ikaOdkh
ú≥,s ikafoaY f,dfjys m%n,;u ikaOdkh
ú≥,s ikafoaY f,dfjys m%n,;u ikaOdkh
ú≥,s ikafoaY f,dfjys m%n,;u ikaOdkh
1865 ° werö ITU (International Telecommunication
Union) kue;s ix.uh" f,dj ú≥,s ixfoaY lghq;= ms<sn|j
;;aa;aj iy;sl ms˙kukakd f,i ye¢kafjkjd'
1947 ° ITU ixúOdkh tlai;a cd;Ska f.a (United
Nations) tackaishla njg m;a jqKd' úúO rgj, ≥rl:k
National Goverments -
ITU-Tg iïnkaO rdcH wdKavq ^rgj,a& 200la muK
;sfnkjd' thg tlai;a cd;Ska f.a ixúOdkhg wh;a rgj,a
ish,a, u mdfya wh;a h'
Sector members
fï .Khg jefgkafka ≥rl:k iud.ï" ≥rl:k Wmdx.
iud.ï" m˙.Kl Wmdx. ksIamdokh lrk iud.ï" f,dj
m%n,;u ;dCI◊l iud.ï h' ^ikaksfõokhg w∞<&' fuys
idud‚l;ajh 500la muK fõ' fuys idud‚l ms˙i w;rg
jefgk f,dj m%uqL fmf<a iud.ïj,g W∞yrK my;
≤lafõ'
≥rl:k iud.ï (- (AT&T, Vodafone, Worldcom)
≥rl:k Wmdx. ksmojk iud.ï () (Cisco, Nokia, Nortel)
m˙.Kl Wmdx. ksmojk iud.ï () (Compaq, Sun,
Toshiba) udOH iud.ï - (AOl Time, Warner, CBS, Sony)
fjk;a iud.ï - Boeing, Samsung, Xerox
Associate Members -
fï .Khg jefgkafka hï hï úfYaIs; wOHhkhka
lrk lKavdhï h'
Regulatory Agencies-
ú≥,s ikafoaY jHdmdrh flfr® wjOdkfhka isák wdh;k
fï .Khg jefÜ' ^W∞ () US Federal Communication
commission)
ITU - Tys ldr®hh jkafka ≥rl:k" fg,s.%d*a yd o;a;
yd f;dr;=re ikaksfõok w;=re uqyqK;aj,g ;dCI◊l
;;a;aj iy;sl b†˙m;a ls¯uhs'
cd;Hka;r ;;a;ajlrKfha uQ,sl u n,dfmdfrd;a;=j ta
ta w∞< fCIa;%hkays cd;Hka;r Ndú;dj" fmd≥ kHdhkag
wkq.; ls¯uhs' b;ska ≥rl:k iïnkaOfhka f,dj
ksr®Kdhlhka imhkafka ITU-T ixúOdkhhs'

7. 16
ú≥y,
2008 foieïnr® 10
;dlaaIK wxYh wfma m%jdo-2
wfma m%jdo-2
wfma m%jdo-2
wfma m%jdo-2
wfma m%jdo-2
lr®;D-k,ska o is,ajd
ú≥ir mqj;a mf;ys jir
6lg wêl ld,hla uqΩ,af,a
i;sm;d m< jk wfma m%jdo
,sms fm<g wh;a ;j;a ,sms
56la we;=<;a wfma m%jdo-2
lD;sh miq.sh od uqøK
oajdrfhka t<s ≥gqfõ h' óg
fmr m< jQ wfma m%jdo-1
lD;sfhys wfma m%jdo ,sms
fm<g wh;a uq,a ,sms 59la
we;=<;a j ;sì◊'
f,aLlhdg wkqj" wfma
m%jdo ksr®udKh ls¯u
iïnkaOfhka úfYaIfhka u
isiq mrmqr ±kqj;a ls¯u fuu ,sms tl;=fjys uQ,sl wruqK
fõ' ngysrhka ;uka ksr®udKh lrk ≤kqfï uysufhka
f,dj md,kh lroa° wmg Tjqka f.a n,mefuka ksoyia
úh yelafla wfma u ±kqula ksr®udkh ls¯fuka h hkak
bka wjOdrKh flfrhs'
wfma m%jdo-2 lD;sh o fndr,eia.uqj jej mdfr® wxl
471ys msysá úis≥kq wdh;kfha m%ldYkhls' ^0112518882&
YS%,xld udOH kdudj,sfha
YS%,xld udOH kdudj,sfha
YS%,xld udOH kdudj,sfha
YS%,xld udOH kdudj,sfha
YS%,xld udOH kdudj,sfha
8 jk ixialrKh ksl=;a fõ
8 jk ixialrKh ksl=;a fõ
8 jk ixialrKh ksl=;a fõ
8 jk ixialrKh ksl=;a fõ
8 jk ixialrKh ksl=;a fõ
Y%S,xldfõ ckm%sh;u udOH kdudj,sh jk Or®uka f.a
udOH kdudj,sfha 8 jk ixialrKh ±ka ksl=;a ù ;sfì'
udOHfõ°ka fukau fmd≥ ck;djg o udOH f;dr;=re
fidhd .ekSfuys ,d ukd
msájy,la jk fuh f–HIaG
mqj;am;al,dfõ° Or®uka
úl%ur;akhka f.a
ixialrKhls' msgfldaÜfÜ
Y%S kd.úydr udjf;a 375$2
msysá md˙i˙l ckudOHfõ°
mr®Iofha m%ldYkhla jk
fuu .%ka:hg fujr
udOHhg iïnkaO wdh;k
810l o;a;hka 7972la
we;=<;a ù ;sfí'
cd;sl iy cd;Hka;r
jYfhka udOH iy
uyck;dj w;r l%udkql=,
iïnkaO;djla f.dvkÛd
.ekSug bjy,a jk fuu
kdudj,sh msgq 280lska
iukaú; w;r úúO wdh;k 810l kduhka 1633la" fjí
wvú 556la" ,smskhka 554la" cx.u ≥rl:k wxl 1117la"
ia:djr ≥rl:k wxl 1833la" *elaia wxl 646la" úoHq;a
;eme,a ,smsk 823la tlg tla l< Y%S ,xldfõ úYsIag;u
kdudj,shls' tfuka u fuu .%ka:hg l,d.dr 28la"
ixlD;sl wdh;k 20la" kdgH rÛy,a 28la" ixjr®Ok wdh;k
21la" †ia;%sla f,alï ldr®hd, 20la" ;dkdm;s ldr®hd,
36la" rcfha udOH wdh;k 03la" úfoaY m%jD;a;s wdh;k
36la" cd;sl yd m%foaYSh ckudOH ixúOdk 66la" ckudOH
mqyqKqlrejka 26la" wud;HxY 85la" †km;d mqj;am;a 11la"
i;sm;d mqj;a m;a 34la" udisl mqj;am;a 18la" foaYmd,k
mlaI 16la" .=jka ú≥,s wdh;k 14la" tf;r YS% ,xld
;dkdm;s ldr®hd, 39la" ù° kdgHh lKavdhï 15la" udOH
mqyqKq wdh;k 14la" rEmjdyskS wdh;k 15la hk
wdh;khkays ,smskhka" wdjrKh lrk m%foaY iy tajdfhys
l%shdldrlï we;=Ω ;j;a f;dr;=re .Kkdjla wvx.= h
fuu .%ka:h ms<snoj jeä úia;r YS% ,xld md˙i˙l
ckudOHfõ° mr®Ioh" 375$2 YS%kd.úydr udj;" msgfldaÜfÜ
hk ia:dkhg meñ”fuka fyda 071-2733986 ≥rl:kh
weu;Sfuka fyda ,nd.; yels h'
mqia;ld,h
wka;r® cd;sl ;;a;aj iy;sl
wka;r® cd;sl ;;a;aj iy;sl
wka;r® cd;sl ;;a;aj iy;sl
wka;r® cd;sl ;;a;aj iy;sl
wka;r® cd;sl ;;a;aj iy;sl
ms˙kuk m%Odk ixúOdk
ms˙kuk m%Odk ixúOdk
ms˙kuk m%Odk ixúOdk
ms˙kuk m%Odk ixúOdk
ms˙kuk m%Odk ixúOdk
m˙.Kl cd,lrKfha wka;r®cd;sl ;;a;aj iy;sl
ms˙kuk m%Odk;u wdh;kh jkafka ISO h' (International
Standards Organization). 1946 ° werô fuu ixúOdkhg
rgj,a 89l ksfhdackhla we;' ta w;r wefu˙ld tlai;a
ckmofha ANSI ixúOdkh;a" ì%;dkHfha BSI ixúOdkh;a"
m%xYfha AFNOR ixúOdkh;a" cr®uksfha DIN ixúOdkh;a
m%Odk jk w;r ;j rgj,a 85l ksfhdackh;a fuys ;sfí'
we;af;ka u ISO hkq m˙.Kl cd,lrK ;;a;aj iy;sl
ms˙kuk wdh;khla u fkd fõ' Tn wid we;s wkaoug"
wek uq˙ÉÑfha isg kùk Wmdx. olajd ;;a;aj iy;sl
ksl=;a lrk wdh;khls' fr†ms<s" wdydrmdk" bf,lafg%dksl
Wmdx. jeks úYd, mrdihkays †fjk øjH" NdKav yd
Wmdx. rdYshlg ;;a;aj iy;sl ISO uÛska ksl=;a flfr®'
b;ska" ú≥,s ixfoaY lghq;= ms<sn| ;;a;ajlrKfha °
(Standardizing Telecommunication) ISO wdh;kh ksr;=rej
ITU-T iuÛ lghq;= lrhs' ^ISO wdh;kh ITU-T wdh;kfha
idud‚lhls&' tf,i in|;d ;nd.kafka wka;r®cd;sl ;;a;aj
iy;sl ms˙keófï ° u;=jk .eg¨ uÛyrjd .ekSug h'
ISOys wefu˙ldkq ksfhdackh ANSI wdh;khhs'
(American National Standards Orgnaization). tys kñka th
wefu˙ldkq rdcH wdh;khla hehs yeÛ=K o th fm!oa.,sl"
rdcH fkd jk" ,dN wfmaCId fkd lrk wdh;khls' tys
idud‚l;ajh orkafkda ksIamdoljre" fn∞y˙kafkda yd
;;a;ajlrKhg <ne¢ wfkl=;a mdr®Yajfhda h' ISOys
ls%hdld˙;ajh my; m˙† fõ'
hï m%foaYhlg wdfõ◊l$fjka jqKq wka;r®cd;slj ms<s.;a
;;a;ajlrKhla (international standards for an area) wjYH
kï uq,ska u is≥ jkafka ;;a;aj wjYH lKavdhfuka
ksYaÑ; lñgqjla yryd fhdackdj f;dard .ekSuhs'
(Committee draft). miqj th" ta w∞< m%dfoaYSh idud‚lhka
fj; fn∞ foa' udi 6la .; jQ miq th ia:ßrj u iïu;
fjkjd kï" jvd;a ksje/†" ,faLkhla (Draft International
Standard) ielfia' wk;=rej th ISOys w∞< idud‚lhka
w;fr® Pkaolhlska f;dard .efkhs' jeä Pkaohlska th
iïu; jqj fyd;a thg ISO iy;slhla ms˙kefuhs'
(International Standard). fï ls%hdj,shg jir .Kkdjla
.; úh yels h'
m˙.Kl cd,lrKh yd ú≥,s ixfoaY lghq;= ms<sn|
;;a;aj iy;sl ms˙kuk ;j;a wdh;khla jkafka wefu˙ld
tlai;a ckmofha NIST I (National Institute of Standards
Technolgoy) wdh;khhs' fuh wefu˙ldkq jd◊c
fomdr®;fïka;=fõ' (Department of commerces) tla wxYhls'
fuh wefu˙ldfõ cd;sl ;;a;ajlrK wdh;kh kñka
ye¢kaú◊' NIST wdh;kfhka iy;sl ksl=;a flrefKa"
wefu˙ldkq rch ,nd.kakd iEu w;HjYH Wmdx.hlg u
h' ^wdrCIl wud;HxYhg yer&
wefu˙ldkq wdrCIl wud;HxYh hgf;a we;s iEu
wdh;khl u rgg wdfõ◊l jQ ñKqïo~q we;s fyhska
NIST fï ;;a;ajlrKhka ksl=;a lrkafka ke;'
IEEE
m˙.Kl cd,lrK ;;a;aj iy;sl ksl=;a ls¯fï ;j;a
m%Odk;u yd iqúfYaIS u wdh;khla kï" f,dj úYd,;u
jD;a;Shuh ixúOdkh jk IEEE wdh;khhs' (Institute of
Elcetrical & Electronic Engineers). th f,dj isák ú≥,s
yd úoHq;a bx‚fkdarejka f.a ixúOdkhhs' (IEEE - Sri Lankan
section kñka tys YS% ,dxlsl wxYhla o fjhs&
IEEEys ;;a;aj iy;sl ms˙keóu i|yd ^ú≥,s yd
m˙.Kl bx‚fkare fCIa;%fha& fjk u lKavdhula fjhs'
IEEEys 802 kï lñgqj LAN (Local Area Networks) i|yd
;;a;aj iy;sl .Kkdjla u ksl=;a lr ;sfí' my;
≤lafjkafka tu jr®.SlrKfhka h' IEEE 802 ldKav hgf;a
we;s ;;a;ajrlKhka (IEEE 802 Standards) my; j.=fjka
fmkakqï flfr®'
Number Topic
802-1 Overview & Architecture of LANs
802-2 Logical Link Control
802-3 Ethernet
802-4 Token bus (Was used in manufacturing
plants)
802-5 Tolken ring (IBM's entry into the LAN
world)
802-6 Duel Queue Dual Bus (ealy MAN)
802-7 Technical Advsary Group on Broadband
802-8 Technical Advisay Group on Fiber optics
802-9 Isochronous LANs
802-10 Virtual LANs security
802-11 Wireless LANs
802-12 Demand priority (HPs AnyLAN)
802-13 (Unluclcky 13-No Topic)
802-14 Cable modems
802-15 Personal Area Networks (Bluetooth)
802-16 Broadband Wireless
802-17 Resiliant Packet Ring
fyd|hs wms ta ir,j wjOdkh fhduq lf<a Networks
Standardization hk ixl,amh ms<sn|j' ±ka ud leu;shs
Tng m˙.Klh iy m˙.Kl cd,lrKh iuÛ ine†
ñkqï tall ^Metric Units& ;=k fláfhka úia;r lrkakg'
m˙.Kl f,dj l=vd u tallh bit 1la hkakhs'
1 byte = 8 bits
kB-Kilo Byte MB-Mega Byte GB-Giga Byte
TB-Tera Byte
1kB =1024 bytes
1MB =1024 kB = (210
)2
bytes = 1048 576 bytes
1GB = 1024 MB = (210
)3
bytes =1073 741 824 bytes
1Mbps hkq 1 Megabits per second -;;amrhg ìÜ
106
l m%udKhla heùu hkakhs'
wms ,nk i;sfha w¨;a ud;Dldjlska yuq fjuq'
;˙∫ úrisxy
;˙∫ úrisxy
;˙∫ úrisxy
;˙∫ úrisxy
;˙∫ úrisxy

8. 16
ú≥y,
2008 foieïnr® 24
;dlaaIK wxYh
≥rl:k cd,
≥rl:k cd,
≥rl:k cd,
≥rl:k cd,
≥rl:k cd,
jr®;udk f,dalfha ikaksfõok ;dCIKh b;d †hqKq
;;a;ajhlg m;a ùug n,mE m%Odk idOl jkafka ≥rl:k
yd ≥rl:k cd,hs' fuu ,smsh lshjk Tng;a ≥rl:khla
^cx.u fyda ia:djr& we;ehs úYajdi lrñ' ta ;rug wo
≥rl:k Ndú;h jHdma; ù yudr h'
§≥rl:k¶ hk ixl,amh;a" ≥rl:kfha m<uq
ksr®udKd;aul iajrEmh;a f.k wdfõ wef,laiekavr® .%eyeï
fn,a (Alexander Graham Bell) h' ta 1876 ° h' bka
wk;=rej" jr®;udkh olajd ≥rl:kfha m˙Kduh b;d
YS>%fhka is≥ úh' wms fï ,smsfha mgka" ;rula ≥rg ≥rl:k
cd, ms<sn|j idlÉcd lruq'
Public Switched Telephone Networks (PSTNs)
≥rl:k .Kkdjla tlsfkl iïnkaO jk cd, wms
PSTNs f,iska y∫kajuq' fndfyda úg fuu ≥rl:k cd,
tlsfkl iïnkaO jkafka Switching office tlla yryd h'
ta ksid wms tu cd,j,g Public switched hk úfYaIK
mohla tl;= lruq'
PSTNs ixl,amh we;s jqfKa §≥rl:kh¶ (Telephone)
hk ixl,amh we;s jQ ieksks' PSTNs we;s ùug uQ,slj u
n,mE fya;=j jQfha ukqIH lgy~ i‚új iïfma%IKh ls¯ug
;snQ wjYH;djhs' (Transmitting human voice in a recognizable
form). .%eyeï fn,a f.a ≥rl:k moaO;sh" ≥rl:k 2lska
iukaú; jQ w;r ta ≥rl:k fol tlsfkl iïnkaO jQfha
w∞< md˙fNda.slhd úiska ñ,hg .kakd ,o jhrhlsks' ta
wkqj" tla ≥rl:k .%dylhl=g ;j;a flkl=g weu;Sug
wjYH kï ta w∞< .%dylhd f.a ≥rl:kh yd ;uka f.a
≥rl:kh jhrhlska iïnkaO l< hq;= j ;snqKs' b;ska" ta
wdldrhg tla ≥rl:k .%dylhl=g ;j;a .%dylhka
.Kkdjlg weu;sh hq;= kï ta tla tla wh f.a ≥rl:k
iuÛ jhrj,ska iïnkaO úh hq;= úh' th b;d u ixlSr®K
cd,hla njg m;a ú◊' ^cxcd,hla lsõfjd;a ksje/†hs&
by; ≤lafjkafka l,ska i|yka l< wdldrfha ≥rl:k"
ksjfika ksjig jhr uÛska iïnkaO jk wdlD;shls'
Tng u fmfkkjd we;s tys we;s ixlSr®Klu' ^rEm igyfka
≤lafjkafka ksfjia 6la w;r in|;djla muKhs' ys;kak"
ksfjia 100la -1000la muK iïnkaO lrkafka fldfydu
o lshd&' b;ska fuu wdlD;sh" Wmka f.hs u urd ≤uqKs' ta"
tys we;s ≥r®j,lu ksid h' Bg ms<shula f,i uOH.;
yqjudrejla (Centralized switch) uÛska ≥rl:k .%dylhska
iïnkaO lrkakg" .%eyeï fn,a ixl,amhla f.kdfõ h'
^my; rEm igyk n,kak&
1878 ° wefu˙ldfõ ksõ fyjkays ° (New heaven -
Conneticut) fuu" m%:u uOH.; yqjudrej (Centralized
switch) ia:dms; flreKs' fuys ° is≥ jkafka" .%dylhl=g
≥rl:k weu;=ula ,nd.ekSug wjYH jQ úg" Tyq ish
≥rl:kfhka uOH.; yqjudrefjys kdohla we;s ls¯u h'
túg tys isák ls%hd lrjkafkla tu weu;=u w∞< wfkla
mdr®Yajhg iïnkaO lrhs'
fuu wdlD;sh YS>%fhka wefu˙ld tlai;a ckmoh mqrd
ckms%h úKs' tfy;a l%ufhka" ≥rl:k Ndú;dj yd
tlsfklg fndfyda wE;ska msysá k.r w;r ≥rl:k
in|lïj, wjYH;dj jeä jk úg fuu l%uh o idr®:l
fkd ù h' Centralized Switching Offices k.r mqrd we;s jQ
w;r tajd jgd .%dylhska tla úh' tfy;a fuu Switching
offices tlsfkl iïnkaO ùu" ;rula ixlSr®K úh' ukao"
fndfyda wE;ska msysá k.rj, we;s fuu Switching offices
ish,a, u tlsfkl iïnkaO ls¯u m%dfhda.sl .eg¨jla jQ
neúks' b;ska" Bg ms<shula f,i fojk fm< yqjudre
tall (Second level Switchign Units) we;s fl˙◊'
by; rEm igyfkka ≤lafjkafka" fmr lS fojk fm<
yqjudre ia:dk iy uOH.; yqjudre ia:dkj, wdlD;shls'
1890 jk úg ≥rl:k moaO;shl m%Odk wx. f,i
yqjudre ia:dk (Switching offices), .%dylhd iy yqjudre
ia:dk w;r iïnkaOl yd yqjudre ia:dk tlsfkl iïnkaO
flfrk iïnkaOl (Long distance connection between the
switching offices) ia:dms; ù ;snqKs' 1984 jr®Ihg m%:u
≥rl:k moaO;sfha ^wefu˙ld tlai;a ckmoh ;=<& wdlD;sh
≤ka ir,j meye†,s lrkakï'
iEu ≥rl:khlg u ;U jhr 2la ;snqKs' fuu jhr
fol fl<ska u iïnkaO jQfKa w∞< ≥rl:k iud.fï <Û
u msysá ldr®hhd,g h' (end office). tu ≥r m%udKh 1km
Centralized
switch
123456
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123456
123456
123456
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123456
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12345
12345
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isg 10km olajd jqKs' wefu˙ld tlai;a ckmofha muKla
tjka ldr®hd, 22000la muK ta jk úg msysgd ;snqKs' tu
ldr®hd, Local central offices hk kñka o ye¢kajqKs'
≥rl:kh yd tu ldr®hd, iïnkaO jk ;U jhr hq.,
Local loop f,i y∫kajk ,†' ta jk úg mD:ßúh u; ;snQ
ish¨ u Local loops tlsfkl iïíkO l< fyd;a ta ish,af,ys
u †." mD:ßúfha isg pkaøhdg we;s ≥r fuka 2000 j;djla
muK jk nj lshefõ'
tlu end office tlla hgf;a bkakd .%dylhka fofokl=
w;r ≥rl:k ixjdohla we;s jk wjia:djl" tu end
office tl úiska ta .%dylhka fofokd w;r ú≥,suh
in|;dj;a we;s flfrhs' ixjdoh wjika jk ;=re fuu
in|;dj mj;S'
weu;=u ,nk ≥rl:kh we;af;a fjk;a end office tlla
hgf;a kï" fjkia wdldrhl ;dCIKhla Ndú; flfr®'
iEu end office tllska u msg;g hk jhr® ;sfnk w;r
tu jhr iïnkaO jkafka wi, u we;s yqjudre ia:dkhkag
h' ta ia:dk wms Toll offices hkqfjka y∫kajuq' End office
tllska msg;g tk jhr Toll connecting frunks f,i
ye¢kafõ' ≥rl:k weu;=u fok iy ,nk ≥rl:k fofla
u end offices tl u Toll office tllg iïnkaO flfrk
Trunks ;sfí kï" tu weu;=u i|yd w∞< in|;dj we;s
lrkafka ta w∞< Toll office tl h'
tfia" fkd fõ kï" tkï we;af;a ≥rl:k weu;=u fok
iy ,nk ≥rl:k folg w∞< tl u Toll office tlla fkd
fjhs kï tys in|;dj we;s lrkafka ;rula by< ia:rhl
we;s ;eklsks' ^m%d:ñl" oaú;Shsl iïnkaOl uÛska&'
my; rEm igyk Tng fï ms<sn|j ;j≥rg;a meye†,s
woyila ,nd fohs'
by; ≤lafjkafka 1984 muK jk úg wefu˙ld tlai;a
ckmoh ;=< Ndú; jQ ≥rl:k iïnkaOl wdlD;shhs' fuu
wdlD;s rfgka rgg fjkia úh yels h' thg fya;=j ta ta
rfgys ≥rl:k Ndú;dfõ m%udKd;aul fjkihs'
wms B<Û ,smsfhka ;j≥rg;a fï ms<sn|j l:d lruq'
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
Telephone
End office Toll office
Local loop
Toll
connecting
trunk
Very high bandwidth
intertoll trunks
Toll
connecting
trunk Local loop
Telephone
Intermediate
switching office
Toll office End office

9. 16
ú≥y,
2009 ckjd˙ 7
;dlaaIK wxYh
≥rl:k ikaksfõokh .ek
≥rl:k ikaksfõokh .ek
≥rl:k ikaksfõokh .ek
≥rl:k ikaksfõokh .ek
≥rl:k ikaksfõokh .ek
;j≥rg;a
;j≥rg;a
;j≥rg;a
;j≥rg;a
;j≥rg;a
≥rl:k cd, iïnkaOfhka uQ,sl ye¢kaùula óg fmr
,smsfhka b†˙m;a l<d Tng u;l we;s' wo ,smsfhka ;j
≥rg;a wms ≥rl:k ikaksfõokh yd ne∫Kq jeo.;a lreKq
lsysmhla idlÉcd lruq'
≥rl:k moaO;shla m%Odk jYfhka fldgia 3lg fnod
oelafjhs'
1. Local loops (Analog twisted pairs going in to houses
businesses)
2. Trunks (Digital fiber optics connecting the switching
offices)
3. Switching offices (Where calls are moved from one
trunk to another local loop).
^miq.sh ,smsfhka Local loops, Trunks, Switching offces
.ek ye¢kaùula ,nd ≥kakd Tng u;l we;s' Bg wu;rj
fï ish,a, u tlg iïnkaO jkafka flfia ±hs ±lafjk o<
rEmigykla o b†˙m;a l<d Tng u;l we;s'
±ka wms m˙.Klhlska m˙.Klhlg ≥rl:k udr®.
Tiafia iïnkaO jkafka flfia ±hs n,uq' my; rEmigyk
fyd¢ka ks¯CIKh lrkak'
jeo.;a (- Looal loops hkafkys m%Odk wx. 3ls'
1. MODEMS
2. ADSL
3. Wireless
by; rEmigykska ±lafjkafka m˙.Klfha ISP (Internet
Service Provider) tllg tfyu;a fkdue;s kï wka;r®cd,
myiqlï ,nd fok n,j;a m˙.Klhlg (Server) ≥rl:k
udr®. yryd iïnkaO jk whqre h' Analog signals ^ú≥,suh
ix«d&" Digital signals ^1-0 wdldrfha ix«d& njg
fmr<kafka Modems u.sks' Digital signals, Analog Signals
njg m;a lrkafka Codecs u.sks'
rEmfha ISPL foi n,kak' th Modem bank tllska
iukaú; h' Modem bank tlla hkq Modems rdYshlska
ie≥ï ,;a tallhls' fï Modem tl tlla úúO Local
loopsj,g iïnkaO fõ' tu.ska ISP tllg tljr m˙.Kl
rdYshlska ,efnk requestsj,g lka †h yels w;r ta ta
m˙.Kl iu. o;a; yqjudrej is≥ ls¯ug o ms<sjk'
o;a; yqjudrefõ ° we;s jk .egÆ
o;a; yqjudrefõ ° we;s jk .egÆ
o;a; yqjudrefõ ° we;s jk .egÆ
o;a; yqjudrefõ ° we;s jk .egÆ
o;a; yqjudrefõ ° we;s jk .egÆ
(Problem in transmission)
o;a; hjkakd f.a isg ,nkakd olajd .uka .ekSfï °
(Senders Computer to Receivers computer) tu ix{dj,
Yla;sh wvq fõ' fuh wms Attennuation f,iska y∫kajuq'
th o;a; iïfma%IKfha ° wm uqyqK fok m%n, m%Yakhls'
;j;a .eg¨jla jkafka tla tla ix«d (Signals) tla
tla fõ.fhka Transmission lines ;=<ska .uka ls¯uhs'
fuu ix{d ,nkakd f.a wka;fha (Receivers end) ix{d
tyd fuyd ùulg ;=vq fohs' wms th Distortion f,i y∫kajuq'
wkjYH ix{d fldgia (Unwanted energy signals) wm
hjk ix{djkag tl;= ùu ;j;a .eg¨jls' wms fuh
addition of noises f,iska y∫kajuq Noises jr®. 3ls'
Noise
Thermal noise Impulse noise
Cross talks
Thermal Noise :- o;a; iïfma%IKh lrk jhrj,
(Trasmission lines) bf,lafg%dakj, wyUq p,s;h ksid ckkh
jk ;dm ix{d (Thermal signals) ksid Thermal Noises
we;s fõ'
Cross Talks :- úfgl Tn ≥rl:kfhka l:d lrk úg
Tn yd Tn wu;k mqoa.,hd f.a ixjdohg wu;rj Bg
miqìñka ;j;a ixjdohla ^;j fofokl= w;r& weiS we;=jdg
iel ke;' fuhhs wms Cross talks f,i y∫kajkafka' Cross
talks we;s jkafka ikakdhl jhr foll tlsfkl uqyq
ùula ksid we;s jk wfkHdkH úoHq;a fma%rKh ksid h'
Impulse Noise :- fuh we;s jkafka ix«d iïfma%IKh
lrk jhrj, we;s keùï ksid h' Digital o;a; i|yd fuu
Noise jr®.h ke;s lr.; yelafla bit jeä m%udKhla
iïfma%IKh ls¯fuks'
MODEMS
wmg 1-0 w;r †fjk ä‚g,a ix{d Digital
signals - Square waves) fndfyda ≥rlg
iïfma%IKh l< fkdyels h' fya;=j tu ix{d
b;d mqΩ,a ixLHd; mrdihl †fjk ksid;a
by;ska i|yka l< Distortion yd Attenuation
hk w;=reM,hkag uqyqK fok ksid;a h' b;ska
wmg ,efnk ä‚g,a ix«d ^m˙.Klhlska
wmg ,efnkafka Digital ix{d h') wekaf,d.a
(Anlog signals) njg m˙jr®;kh lr
iïfma%IKh l< hq;af;a tneúks' Digilal ix«d
Analog ls¯ug;a Analog ix«d Digital ls¯ug;a
Ndú; jk WmlrKhls MODEM tl'
wka;r®cd, myiqlï ,nd.ekSug fuu
WmlrKh Ndú; lrkjd we;'
Modem hk jpkh ksr®udKh ù ;sfnkafka MODulate
DEModulate hk jpk fofla lemsg,aj,ska olajd we;s
wl=re .e,mSfuks'
Modulation hkq Digital ix« Analog njg m;a ls¯fï
hdka;%Khhs'
Demodulation hkq ,efnk Analog ix«djla fmr ;snQ
Digital ;;a;ajhg m;a ls¯uhss'
Modems, o;a; úYd,;ajh wvq jk f,i weis¯u;a (Data
compression), fodaI .%yKh ls¯u;a (Error Detection) is≥
lrhs'
wm Ndú; lrk Modems 56kbps fyda 56.6kbps o;a;
fõ.hkag wkql=, fõ' tu fõ.hkaj,g o;a; iïfma%IKh
lrkqfha 8kbps fõ.hg Tfrd;a;= fok jhr (Transmission
lines) yryd h' tjka Modems whs;s jkafka V.92 hk
;;a;ajlrKhg h'
±ka Modem tlla ;=< Ndú; jk Modulation Schemes
tkï Digital ix«djla Analog lrk l%ufõoh fmkajd
fokakï' tjka l%ufõo 3la we;' bka 2la Tng b;d yqremqre≥
h' .=jka ú≥,s ;rx. iïfma%IKfha ° o tu l%ufõoh
Ndú; fõ' ta" AM (Amplitude Modultion) yd FM (Frequency
Modulation) h' wfkla l%uh Phase Modulation hkak h'
fuu ;rx. rEm igyk n,kak' fuh wo wfma úIhg
t;rï wjYH fkd jqK;a ;rx.hl uQ,sl ,CIK Tn
y∫kd.; hq;= hehs ud úYajdi lrk ksid th we;=<;a
lf<ñ'
by; rEmigyfka ±lafjk ;rx.j,g wms fmd≥fõ Sine
waves ^ihskdldr ;rx.& hehs lshuq' fmd≥fõ wms tu
;rx. A Cos (wt-tx) f,iska kï lruq'
A - ;rx.fha úia;drh (Amplitude)
W - ;rx.fha flda◊l m%fõ.h (Angular velocity)
T - ld,h (Time)
K - ;rx.fha wxlh (Wave number)
X - X w.fha we;s úp,kh ^by; rEmigyfka kï λ&
L - ;rx. wdhduh (Distance traveller per period)
T - wdjr®; ld,h (Period)
F - ixLHd;h ^t=1/ f tall ld,hl ° iïmQr®K lrk
wdjr®; .Kk&
E - ;rx.fha Yla;sh
Rx hk moh Φ f,i o wms ,shuq' Φ hkq ld, fjkihs'
(Φ -Phase angle)
fyd|hs ±ka my; rEmigyka n,kak' uq,ska u we;af;a
ä‚g,a ix{djls' bka miqj we;af;a tu ix{djg Amplitude
Modelation tl hgf;a Modulate l< úg ,efnk ix{djhs'
bka miqj Frequency Modulation tflka ,efnk ix«dj;a
bka wk;=rej Phase Modulation tflka ,efnk ix{dj;a
olajd ;sfí'
(a) Digital signal
(b) Amplitude modulation
wog ,smsh fu;ekska wjika lruq' B<Û ,smsfha ° wms
l;d lrkafka Local Loopsj, ;j;a wx. 2la jk ADSL
yd Wireless Loops .ek;a Trunks yd Suiteling .ek;a h'
hkq Locld loops, Trunks yd Suiteling hkq Telephone system
tl; m%Odk wx. 3 nj Tng u;l we;s'
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
Computer
→
Modem
→
→
Endoffice
Codec
Toll
office
Toll
office
Codec
→
→
Codec
→
Modem bank
ISP1
ISP2
→
Medium-bandwidth
trunk
(Digital, Fiber)
Digital line
→
Local loop
(Analog Twisted pair)
Up to 10000 local loops
Toll
office
ISP1, ISP2 → Internet Services providers 142
0 λ 2λ
λ ;rx. wdhduh
;rx. wdhduh
;rx. wdhduh
;rx. wdhduh
;rx. wdhduh
A
x
E = [A cos (wt-kx)]
(c) Frequency modulation
(d) Phase Modulation
MODEM tlla
→
→

10. 19
ú≥y,
2009 fmnrjd˙ 4
;dlaaIK wxYh
miq.sh ,smsfhka wms" Local loopsj, tla wx.hla jk
Modems .ek l;d l<d' wo Local loops j, wfkla wx.
fol jk ADSL yd Wireless Loops .ek l;d lruq'
ADSL (Asymmeric Digital Subscriber Line)
≥rl:k ikaksfõokfha ° o;a; .,d hdfï fõ.h 56kbps
olajd jeä jqKd' ta jdf.a u Cable TV lr®udka;h;a YS>%fhka
†hqKq jqKd' Cable TV iud.ï 10Mbps o;a; fõ.hla
md˙fNda.slhdg ,nd ≥kakd' b;ska" tf,i u wka;r®cd,h
m˙yrKh;a tkak tkak u jeä jqKd' ≥rl:k iud.ï"
wka;r®cd, myiqlï ,nd °u ;Sj% ls¯fï uQ,sl wä;d,u
f,i jeä mrdihl o;a; .,d hdfï fõ. (Broadband)
,nd °ug ;SrKh l<d' ta i|yd y∫kajd ≥kafka Digital
Subsriber Line - DSL hk ixl,amhhs'
DSL hkq" wka;r®cd, fiajd iïmdolhd (ISP) yd .%dylhd
w;r fkd ìf|k ^ia:ßr& iïnkaO;djla we;s ls¯uhs' DSL
Ndú; lrk úg Dialup udr®.fhka wk;r®cd,hg msúiSu
wjYH keye' DSLys o;a; .,d hdfï fõ.h jeähs' o;a;
Nd.; (Download) lr .ekSfï mrdih yd fõ.h o jeähs'
DSLys m%Odk wruqKq 4la jkjd'
01. Category 3 Twisted pair .Khg jefgk iïnkaOl
u; ls%hd;aul úh hq;= h' (Service must work over the
existing category 3 twisted pair local loops).
02' wka;r®cd,h Ndú; lrk úg .%dylhka f.a ≥rl:k
yd *elaia hka;%j,g ndOd fkd meñKúh hq;= h'
03' o;a; .,d hdfï fõ.h 56kbpsg jvd jeä úh hq;=
h'
04 ks;r u ON ;;a;ajfha ;sìh hq;= h' udisl .dia;=jla
muKla wh úh hq;= w;r Bg ≥rl:k .dia;=jla wh fkd
flfr®' (Should be always ON with just a monthly rental but
no per minute charge)
ADSLys A wl=r ixfla;j;a lrkafka Asymmetric hkakhs'
Asymmetric hkq wiuñ;sl hkakhs' ADSLys ° upload/
upstream yd Download /downstream i|yd Ndú; jkafka
o;a; fõ. 2la ksid Asymmetric hkak wE≥Kd hehs lsj
yels h'
my; ≤lafjkafka idudkH ADSLiïnkaO;djl
wdlD;shls'
Wireless local loops
jhr® rys; udOHhla Tiafia ^jdhqf.da,h& ia:djr ≥rl:k
ikaksfõokh" wireless local loops uÛska is≥ flfr®' 1969 °
ixl,amhla f,i wdrïN jqKq fuh lr<shg meñ◊fha
1998 ° h' (Wired local loops tfyu ke;akï Local loops
hkq fudkjd ≤hs l,ska ,smshl ° y∫kajd ≥kakd Tng
u;l we;s&'
Wireless local loops Ndú; ls¯fï ° we;s fjkialï
Ndú; ls¯fï ° we;s fjkialï
Ndú; ls¯fï ° we;s fjkialï
Ndú; ls¯fï ° we;s fjkialï
Ndú; ls¯fï ° we;s fjkialï
• md˙fNda.slhdg fõ.j;a wka;r®cd, in|;djla ,efí'
^fndfyda ≥rg ADSLj,g iudk&
• md˙fNda.slhd f.a ksjfia jy,fha úYd, wekafgkdjla
(Directional antenna) iú flfr®' th Competitive Local
Exchange carrier kï m%foaYSh iïnkaOl uOHia:dk †Ydjg
t,a, fõ'
• md˙fNda.slhd f.a ≥rl:kh ia:djr h' ix«
jdhqf.da,h yryd meñ◊h o ≥rl:kh ia:djr h'
kj;u Wireles Local Loop moaO;shla jk Local
Multipoint Distribution Service (LMDS) hk fiajdj 1.3GHz
ixLHd;hla olajd ,nd fohs'
LMPSys o< igykla my; rEmfha ≤lafõ'
TRUNKS
Switching offices 2la, Toll offices 2la" Toll office tlla yd
End office tlla tlsfkl iïnkaO jkafka Trunks uÛsks'
Trunks hkq fï iïnkaOl jhr® f,ig Tng ir,j
Wml,amkh lr.; yels h' ^óg fmr Switching, Toll yd
End offices rEm igyka wdY%fhka úia;r lr ;sfnk ksid
ta .ek kej; igyka fkd lrñ&'
Trunk tlla yryd ix{d .,d hdug ie,eiaùfï °
m%Odk jYfhka" tl u ikaksfõok udr®.hla (One trunk)
ix« .Kkdjla iyfhda.fhka Ndú; ls¯ug (Multiplexing)
i,iajhs' tjka ls%hdj,Skag wms Multiplexing hehs lshuq'
tjka Multiplexing l%u lSmhla ;sfí'
1. Frequency Division Multiplexing (FDM)
2. Time Division Multiplexing (TDM)
3. Wavelength Division Multiplexing (WDM)
4. Synchronous Division Multiplexing (SDM)
b;d fláfhka by; i|yka l< Multiplexing techiques
2la y∫kajd fokakñ' Bg l,ska Multiplexying hkak b;d
fláfhka myokakï'
Multipexing →Allows several transmitters to share a larger
transmission capacity ^iïfm%aIl lsysmhlg ;ks iïfm%aIK
udOHhla Ndú; ls¯ug wjia:dj ,nd fohs&'
Frequency Division Multiplexing (FDM)
FDMys ° jkafka" ixLHd;h (frequency)
fldgiaj,g (channels j,g& fn∞ iïfm%aIKh
ls¯uhs'
FDM fhfokafka Analog ix« iuÛhs' iEu ix«jla u
Bg w∞< ixLHd; l=,lhlg (frequ necy Band) we;<;a
lrkjd'
FDMys ls%hdld˙;ajh (Transmitting end yd Receiving
endys °& my; o< rEmigykaj,ska fmkajd foñ'
BP filter - Band Pan filter wkjYH ix« fm%arKh lrhs'
TDM (Time Division Multiplexing)
fuys ° ld,h fldgiaj,g fnfoa'
• TDM i|yd fhd∞ .kafka Digital ix« h'
• tu Digital ix« fma%rKh ls¯ulg Ndckh lrhs'
(Buffer)
• o;a; Frames wdldrhg iïfm%aIKh fjhs'
• Buffers hï m¯CIKhlg (Scanning) n∫ka fjhs'
bkamiq mc
(t) kï Composite signal tlla yefohs'
my; rEmigyka n,kak'
Switching
PSTN ixl,amhg w∞<j wmg l;d lrkakg we;s wjika
ud;Dldj Switching hk ls%hdj,shhs'
óg m%:u m˙.Kl yryd o;a; yqjudrefõ ° fhfok
Switching l%u 2la idlÉcd l<d Tng u;l we;s' Packet
yd Circuit Switching tla l%u 2hs'
≥rl:k ikaksfõokfha o Ndú; jkafka tu Switching
ixl,am folhs' l,ska ,smshl Circuit yd Packet switching
uq,Or®u iúia;rj idlÉcd l< ksid fuys ° ta .ek l;d
lrkafka keye' ta fjkqjg ≥rl:k$wka;r®cd, ikaksfõokfha
° tu Switching l%u fhfok whqre ó<Û ,smsfhka
n,dfmdfrd;a;= jkak'
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
Telephone
line
Voice
switch
Codec
DSLAM
To ISP
Digital
Subscriber
Line
Access
Multiplexer
Telephone Company
end office
NID
Network
Interface
Card
Customer's home (eg.
Your home)
Splitter
ADSL
Modem
Ethernet
Telephone
Computer
Transmission
tower
Telephone
Network
Internet
Service Provider
Signal
Direction
Antenna
Customer's
home
Computer
M
U
X
D
E
M
U
X
i link n channel
'n' inputs 'n' outputs
MUX - Multiplexer
DEMUX - Demultiplexer
Ch
1
Ch
2
Ch
3
Ch
n
f1
f2
f3
f4
fn
Frequency
Time
'Ch' - Channel
'f' - Frequency
m1
(t)
m2
(t)
mn
(t)
mi
(t) s(t)
Transmitter
fc
FDM
Signal
Adding all
Signals
Composite
base band
modulating signal
Subscriber
Modulator f1
Subscriber
Modulator f2
Subscriber
Modulator f3
mi
(t) - Analog signals
Transmitting end
δ(t)
Receiver
m0
(t)
FDM
Signal
BP filter 1
BP filter 1
BP filter 1
Demodulator 1
m1
(t)
m2
(t)
m3
(t)
Demodulator 2
Demodulator 3
BP filter n
mn
(t)
Demodulator n
Receiving end
Ch
1
Ch
2
Ch
3
Ch
n
Frequency
Time
m1
(t)
m2
(t)
mn
(t)
Buffer 1
Buffer 2
Buffer n
Scan
mi
(t) δ(t)
Modem
IDM
Signal
Transmitting end
1 2 3 n 1 2 3 n
Frame Frame
TDM Frames
Modem
δ(t)
Scan
Buffer
Buffer
Buffer
m1
(t)
m2
(t)
mn
(t)
Receiving end

11. 19
ú≥y,
2009 udr®;= 4
;dlaaIK wxYh
cx.u ≥rl:k fiajh
cx.u ≥rl:k fiajh
cx.u ≥rl:k fiajh
cx.u ≥rl:k fiajh
cx.u ≥rl:k fiajh
(Cell phones)
wo jk úg f,dalfha muKla fkd j Y%S ,xldfõ;a
iudkH uyck;dj w; we;s b;d iq,n Wmdx.hla cx.u
≥rl:kh' fuu ,smsh lshjk Tn w;˙ka jeä fokl= u
cx.u ≥rl:khla mdúÉÑ lrkq we;ehs úYajdi l< yelshs'
ta ;rug u cx.u ≥rl:k fiajdj wo jHdma; ù yudrhs'
miq.sh ,ssmsj,ska wm m˙.Kl cd," ≥rl:k cd, .ek
l:d l< ksid wo ,smsfhka wms wms cx.u ≥rl:k moaO;s
.ek ;rula l;d lruq'
myiqfjka Tn fudn f.k hd yels jhr® rys; ≥rl:k
cx.u ≥rl:k f,i y∫kajuq' tfy;a jhr® rys; iEu
≥rl:k jr®.hla u cx.u (Mobile) .Khg fkd jefÜ'
wm fmd≥fõ l:d lrkafka cx.u ≥rl:kh .ekhs' iuyr
úg wms tajd Cell phones f,i o y∫kajuq Cell phones
f,i tu ≥rl:kj,g ku ye≥K yeá miqj ≤k .ksuq'
cx.u ≥rl:k úYd, m%udKfha wjldYhla ;=< o;a;
yd y~ iïfma%IKh lrkakg fhdod .efka'
cx.u ≥rl:kfha b;sydih .ek;a wms fláfhka
wjOdkh fhduq lruq' uQ,sl jYfhka wjê 3la miq fldg
cx.u ≥rl:k fiajdfõ m˙Kduh is≥ ù ;sfí'
ta"
1' wekf,d.a y~ (Aíloyo Voice)
2' ä‚g,a y~ (Digital Volce)
3' ä‚g,a y~ yd o;a; (Digital Voice & Data - Internet,
e-mail)
m<uq mrïmrdfõ cx.u ≥rl:k
m<uq mrïmrdfõ cx.u ≥rl:k
m<uq mrïmrdfõ cx.u ≥rl:k
m<uq mrïmrdfõ cx.u ≥rl:k
m<uq mrïmrdfõ cx.u ≥rl:k
First Generatin Mobile Phones-Analog Voice
1946 ° muK m%:u cx.u ≥rl:k ixl,amh t<s oelajq◊
ta wdrCIl yd hqO fufyhqïj,g Wmldrhla jkq ms◊i
h' ldrhla ;=< ;snqKQ fuu cx.u mKsúv yqjudre lrk
WmlrK moaO;sh uq,ska u ia:dms; lf<a wefu˙ld tlai;a
ckmofha Ydka; ¨ishdys ° h' fuu moaO;sh tla
g%dkaiaógrhlska yd ˙iSjrhlska iukaj; úh' fuys m◊úvh
,efnk úg ˙iSjrh l%shd;aul jk w;r g%dkaiaógrh
l%shd úrys; fõ' m◊úvh hefjk úg g%dkaiaógrh l%shd;aul
jk w;r ˙iSjrh l%shd úrys; fõ' tjeks moaO;s wms Push-
to-talk systems f,i y∫kajuq'
1960 ° IMTS (Improved Mobile Telephone System) we;s
úh' tys ° o wên,e;s (200W) g%dkaiaógrhla fhdod .ekqKq
w;r úfYaI;ajh jQfha m◊úv heùug tla ixLHd;hl=;a
m◊úv ,eîug ;j;a ixLHd;hl=;a Ndú; ls¯uhs' IMTS
pek, 23la yryd m◊úvh heùug bv ,nd ≥ks' ta
150MHz isg 450MHz ixLHd; mrdi w;r h' pek, 23la
hkq l=vd pek, m%udKhla ksid md˙fNda.slhkag Dial
tone tlla weiSug iefyk fõ,djla ≥rl:kfha /£
isákakg is≥ úh' tfukau fuys ° tla moaO;shla i|yd
(One IMTS) fhdod .ekqKq g%dkaiaógrfha m%n,;ajh ksid
wfkla moaO;sh b;d wE;ska ^lsf,daógr ish .Kkla&
msysgqjkakg is≥ úh' ta ixLHd; tlsfkl yemSu je<elaùug
h' (To avoid in interference). bkska fuu moaO;sh (IMTS)
widr®:l ùu ukdj u meye†,s úh'
fï ish,a, wNsnjd 1982 ° wefu˙ld tlai;a ckmofha
AMPS (Advanced Mobile Phone System) msysgqjk ,†' tu
moaO;sh uq,ska u fidhd.ekqfKa wefu˙ld tlai;a ckmofha
Bell úoHd.drfha ° h'
AMPSys ixl,amh wdlD;sh yd l%ufõoh u tx.,ka;fha
TACS f,i o" cmdkfha MCS-L1 f,i o Ndú; flreKs'
ish¨ u cx.u ≥rl:k moaO;sj, tla N+f.da,Sh l,dmhla
Cells lsysmhlg fnod ;sì◊' cx.u ≥rl:kj,g Cell
phone lshd kula mgne∫fKa o tneúks' AMPSj, Cells
10km-20km w;r l,dmhl mej;=◊' fï tla tla Cells
Ndú; lf<a úúOdlr ixLHd;hka (Frequencies) h' tfy;a
tl <Û msysgk Cells lsis úfgl tl u ixLHd;h Ndú;
fkd ls¯ug j.n,d .eks◊'
my; rEmfha A, B, C, D, E, F, H hkq úúO ixLHd; hehs
is;kak' N+f.da,Sh l,dmhla fï wdldrhg ixLHd;
l,dmj,g (Frequeny cells) fnod fjka flre◊'
tla ixLHd; l,dmhl wod< Wm˙u md˙fNda.slhka f.a
.Kkg jvd m˙fNda.sl .ykh jeä jqj fyd;a tu ixLHd;
l,dmh ;j;a l=vd ixLHd; l,dmj,g (Micro cells) fnok
,°'
iEu Cell tll u uOHfha Base Station hehs y∫kajk
≥rl:k iïnkO;d uOHia:dkhla we;' tu l,dmfha
(Cell tfla& ish¨ u ≥rl:k m◊úv heùfï ° t;ekg
iïnkaO fjhs' Base Station tlla m˙.Klhlska"
wekagkdjlg iïnkaO g%dkaiaórhlska yd ˙iSjrhlska
iukaú; h' l=vd moaO;shl kï ish¨ u Base stations
tla WmlrKhlg iïnkaO fjhs' tu WmlrKh Mobile
Telephone Switching Office (MTSO) f,iska ye¢kafjhs' úYd,
cx.u ≥rl:k cd,hl kï MTSO lsysmhla wjYH fõ'
túg tajd o tlsfkl iïnkaO ù mj;S' wms óg fmr l;d
l< PSTNys ° o MTSOj,g iudk End office .ek
i|yka l<d Tng u;l we;s' MTSO o tjeks EnD office
úfYAIhls'
AMPS moaO;sh m◊úv yqjudrej i|yd pek, 832la
Ndú; lf<a h' fï pek, 832 u m◊úv heùug fukau
,nd °ug o fhdod .eks◊' tjka pek, wms Full Duplex
Channels f,i y∫kajuq' fuu pek, 832ys tlsfklla
iu;a jQfha m◊úv heùug pek, 832l=;a" ,eîug 832l=;a
jYfhks' tfia ke;akï heùug yd ,eîug hq., jYfhka
pek, hq., 832la Ndú; úh' m◊úv hjk (Sending
Channels) pek, 824MHz-849MHz ixLHd; mrdih Ndú;
l< w;r m◊úv ,nk jek, (Receiving Channels)
869MHz-894MHz w;r ixLHd; Ndú; lf<a h'
fï 832 pek, ldKAv 4lg fn° ;sì◊'
1. Control (base to mobile) to manage the system
2. Paging (base to mobile) to alert mobile user to call for
them
3.Access (bidircetional) for call setup & channel assignmnt
4' Data (bidirecetional) for voice fax or data
ó<Û ,smsfhka wms cx.u ≥rl:kj, fojk yd f;jk
mrïmrd .ek l:d lruq'
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
óg fmr m< jQ ,smsfha wjidkfha ° i|yka l< Circuit Switching yd Packet Switchlng ^≥rl:k ikaksfõokh °
fhfok& l%shdoduhka tlsfklg fjkia wdlrfhka is≥ jk wkaou ±lafjk o< igykla 2ls'
Circuit Switching
Packet Switching
Switching office
Telephone
Telephone
≥rl:k m◊úvh
wdrïN jQ úg we;s jk
iïnkaOh
Copper connection
fuys ° melÜ ish,a, u tajd hd hq;= ms<sfj<g fmda,sï .eiS isáhs
Switching office
G
A
F
D
G
A
C
A
E
C
E
B
D
G
tla
ixLHd;
l,dmhla
(Cell)
l=vd
ixLHd;
l,dmhla
(Micro Cell)

12. 20
ú≥y,
2009 wm%sfh,a 8
;dlaIK wxYh
Tn okakd m˙† m<uq hq.fha cx.u ≥rl:k §wekf,d.a¶
ix{d l%uhg wkqj l%shd;aul jQ w;r wm wo l;d lrk
fojk hq.fha ° cx.u ≥rl:k ä‚g,a ix{d l%uhg
wj;SrKh úh'
D-AMPS (Digital Advanced Mobile Phone System)
AMPS ms<sn|j miq.sh ,smsfhka Tng lreKq f.kyer
oelajQjd u;l we;s' fojk wjêfha ä‚g,a-ixlSr®K cx.u
≥rl:k fiajdj wms D-AMPS f,i y∫kajuq' D-AMPS
lr<shg tkafka AMPSys l%shdld¯;ajh tf,i u mj;sk
wdldrhgh' AMPS iy D-AMPS hk wdldr fol u tl
cell tlla ;=< ° l%shd;aul úh yels wdldrhg D-AMPS
wm w;rg ths' WodyrKhla f,i D-AMPS moaO;Ska"
AMPS moaO;Ska Ndú; lrk 30kHz pek, u Ndú; lrk
w;r tu ixLHd; (frequencies) u fhdod .kq ,nhs' túg
tla pek,hla §wekf,d.a¶ ix{d Ndú; lrk w;r ta wi,
u mj;sk wfkla pek, ä‚g,a ix{d Ndú; lrhs' tla
cell tll ^ixLHd; l,dmhl& wekf,d.a (Analog) yd
ä‚g,a (Digital) ix{d jr®. fol Ndú; lrk cx.u ≥rl:k
;sìh yels h' túg tu cell tlg ^ixLHd; l,dmhg&
wod< Mobile Telephone Switching Office (MTSO) tl úiska
l=uk pek, ä‚g,a o (Digilal channels) hkak ksr®Kh
flfrhs' tfuka u wjYH fõ,djg pek,fha jr®.h (Chan-
nel type-Analog or Digital) fjkia lrkakg MTSO yg
yelshdj ;sfí' ta" tl cell tl cx.u ≥rl:k jr®. udre
jk úg h'
D-AMPSys úfYAI;ajh
ys úfYAI;ajh
ys úfYAI;ajh
ys úfYAI;ajh
ys úfYAI;ajh (Digital jkafka fldfydu o@
jkafka fldfydu o@
jkafka fldfydu o@
jkafka fldfydu o@
jkafka fldfydu o@)
D-AMPS iys; cx.u ≥rl:khl y~ (Voice signal)
Wlyd .kafka uhsl%f*dakhlsks' tu y~ Wlyd .efkkafka
wekf,d.a ix{d jYfhks' tu ix{d ä‚g,a l%uhg
yerfjkafka Analog to Digal (A/D) converter tllsks' tfia
Digital ix{d njg yerfjk yv (Voice data) §yl=Ωjd
,Sula¶ (Compress ls¯ula& flfr®' th lrkafka Vocoder
kñka ye¢kafjk úfYAIs; m˙m:hlsks' Compression hkq
o;a; jeä bvla ^m%udKhla& fkd .kakd wdldrhg
weis¯uhs'' fuu Compress ls¯u is≥ lrkafka wod< cx.u
≥rl:kfha ° u úkd Base Station tfla° fyda End office
tfla ° fyda fkd fõ'
my; rEm igyfkka oelafjkafka D-AMPS ;dCIKh
cx.u ≥rl:k .%dylhkaa ;sfokl= mdúÉÑ ls¯fï ° fmfkk
o< ieleiauhs'
my; rEm igykska fmkajkafka D-AMPS moaO;sh cx.u
≥rl:k .%dylhka 6 fokl= Ndú; ls¯fï ° b†˙m;a l<
yels o< ieleiauls'
GSM (Global System for Mobile Communications)
D-AMPS ;dCIKh jeämqr u Ndú; jQfha wefu˙ld
tlai;a ckmofha yd cmdkfha h' wfkla iEu rgl u
mdfya Ndú; jQfha$Ndú; jkafka ^fojk cx.u ≥rl:k
hq.h ;=<& GSM ;dCIKhhs'
1982 ° Conference of European Posts 4 Telegraphs
(CEPT) kï tl;=j úiska Groupe Spécial Mobile (GSM)
kñka wOHhk ljhla (Study Group) we;s lr.kakd ,†'
fuu GSM u.ska n,dfmdfrd;a;= jQ wx.hka jQfha''
Good subjective speech quality
Low terminal & service cost
Support for international roaming
Ability to support handled femminals
Support for range of new services
Specfral efficiency
lSDN compatibility
1989 ° GSMys j.lSu European Telecommunication
Standards Institute (ETST)g mej˙◊' GSM m%:u w†hfr®
úfYAI;d (Specifications) uqøKh flrefKa ^ck;djg ksl=;a
flrefKa& 1990 ° h' 1993 jk úg f,dalfha rgj,a 22l
GSM cd, 36la ;sì◊' oekg f,dalfha rgj,a 110l muK
GSM cd, 200lg jeä m%udKhla l%shd;aul fõ'
GSM uÛska iemfhk fiajdjka
uÛska iemfhk fiajdjka
uÛska iemfhk fiajdjka
uÛska iemfhk fiajdjka
uÛska iemfhk fiajdjka
• GSMys uQ,sl u ldr®hh jkqfha Telephony kï fiajdj
iemhSuhs' tkï m%;siu wdldrhg (Analog) mj;sk ñksia
y~ ä‚g,a l%uhg yrjd wfkla wka;fha wikakdg Y%jKh
ls¯ug yels jk whq˙ka iïfma%IKh ls¯uhs'
• óg wu;rj wxl 3la §vh,a¶ ls¯fuka ^Y%S ,xldfõ kï
114" 118" 119 jeks& y†is weu;=ï fiajd ,nd °fï myiqlu
o GSM u.ska iemfha'
• tfukau X.25 fyda X. 32 jeks m%fõY fla; .Kkdjla
Ndú; lrñka POTS (Plain Old Telephone Service), ISDN,
Packet Switched Pubic Data Networks iy Circuit Switched
Public PR Netwares fiajd Ndú; lrkakka fj; 9600 bps
olajd jk fõ.hlska o;a; iïfma%IKh ls¯fï yelshdj
GSM uÛska iemfha'
• GSM hkq ä‚g,a fiajdjla ksid GSM cd,h yd
md˙fNda.slhd w;r m◊jqv yqjudrej i|yd MODEM wjYH
jkafka ke;' tfy;a GSM cd,h ;=< POTS iuÛ m◊úv
yqjudrej Audio Modem tlla wjYH ffõ''
• GSMj, we;s úfYaIs; ,CIKh jkafka wm ljqre;a
fyd¢ka okakd SMS (Short Message Services) fiajdjhs'
th wfkl=;a wekf,d.a m◊úv yqjudre l%u ;=< olakg
fkd ,efnk fiajdjls' SMS hkq oaú †Yd (Bidirectional)
fiajdjla jk w;r nhsÜia 160 (160 bytes) olajd Od˙;djla
fojeks hq.fha cx.u ≥lr:k
fojeks hq.fha cx.u ≥lr:k
fojeks hq.fha cx.u ≥lr:k
fojeks hq.fha cx.u ≥lr:k
fojeks hq.fha cx.u ≥lr:k
(Second Generation Mobile Phones)
we;s wxl yd wlaIr fojr®.h u SMS m◊úvhl wka;r®.;
l< yels h' SMS m◊úv §.nvd lr fn∞ye¯fï¶ (Store-
and-forward fashion) wdldrhg iïfm%aIKh flfrhs'
GSM cd,fha wdlD;sh
cd,fha wdlD;sh
cd,fha wdlD;sh
cd,fha wdlD;sh
cd,fha wdlD;sh
(Architecture of the GSM Network)
GSm cd,h;a m%Odk jYfhka fldgia 3lg fnfoa
GSM Network
Mobile station Network sub section
Base station sub system
my; rEmigyk fyd¢ka n,kak tu rEmfha fmkajkafka
GSM ys ir, u wdlD;shhs'
SIM - Subscrber Identity Module ^≥rl:kfha isï tl&
MS - Mobile Station
BSC - Base Station controller
BTS - Base Transceiver Station
MSC - Mobile Service Switching Cenler
HLR - Home Location Register
VLR - Visitor Location Register
PSTN & ISDN - Fixed networks
wms B<Û ,smsfhka cx.u ≥rl:k ms<sn|j idlÉPdj
wjika lr w¨;a ud;D;djlska yuq fjuq'
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
SIM
MS
BSC
BSC
BTS
BTS
MSC
HLR VLR
PSTN
ISDN
PSPDN
CSPDN
Mobile
Station
Base Station
Sub System
Network
Sub System
υm
A
A
Abis
TDM Frame
Upstream
1850.01MHz
Mobile to base
1 2 3 1 2 3
3 1 2 3 1 2
Dowstream
1930.05MHz
Base to mobile
40ms
324 bit slot
-64 bits of controll
-101 bits of error correction
0159 bits of speech data
TDM Frame
Upstream
1850.01MHz
Mobile to base
1 2 3 4 5 6
6 1 2 3 4 5
Dowstream
1930.05MHz
Base to mobile
40ms
TDM - Time Division Multiplexing

13. 26
ú≥y,
2009 uehs 6
;dlaIK wxYh
cx.u ≥lr:k ;j≥rg;a''
cx.u ≥lr:k ;j≥rg;a''
cx.u ≥lr:k ;j≥rg;a''
cx.u ≥lr:k ;j≥rg;a''
cx.u ≥lr:k ;j≥rg;a''
miq.sh ,smsfhka wm l;d lf<a cx.u ≥rl:k b;sydifha
2 jk hq.h ms<sn|jhs' tys ° wm GSM (Global System
for Mobile Communications) ms<sn|j jeä wjOdkhla fhduq
l<d u;l we;s' wo ,smsfhka" wms cx.u ≥rl:k mrsKdufha
fojk hq.fha ;j;a iqúfYaIS wx.hla jk CDMA ms<sn|
j;a" cx.u ≥rl:kj, 3 jk hq.h ms<sn| j;a l;d lruq'
fï ,smsh" ≥rl:k ikaksfõokh ms<sn| ,sms fmf<a wjidk
,smshhs'
CDMA (Code Division Multiple Access)
jr®;udkfha" /yeka iys; ≥rl:k udr®. ,nd.;
fkdyels fndfyda ksfjiaj, Ndú; jkafka CDMA ≥rl:k
h' ,xldfõ ls%hd;aul jk ≥rl:k fiajd imhkakka
ish,a,ka u mdfya CDMA ;dlaIKh ish md˙fNda.sslhskag
,nd fok nj wo wms oksuq' fudlla o fï CDMA ≥rl:k
lshkafka@
CDMA ≥rl:k /yeka rys; ≥rl:k udr®.hls' tneúka
th cx.u (Mobile) ≥rl:k .Khg jefghs' CDMA ≥rl:k
;dlaIKh" wm uq,ska l;d l< AMPS D-AMPS yd GSM
hk ;dlaIKhg jvd fjkia jQjls'
CDMAys †.yereKq wr®:h Code Division MultipleAccess
hkakhs' ,enqKq ixLHd; mrdih (Allowed frquency range)
l=vd pek, .Kkdjlg fnokjd fjkqjg CDMA u.ska
flfrkafka" iEu ikaksfõok l=¨klska u uqΩ ixLHd;
mrdih mqrd u ix{d iïfma%IKh ls¯uhs' tljr fjkia
ixLHd; Tiafia flfrk iïfma%IKhka fjka lr .kafka
úfYaIs; ¯;shlg (A coding theory) wkqj h'
CDMAys ls%hdld˙;ajh b;d ir,j
• CDMA ;dlaIKh ix{d §nyqúOlrK¶ ;dlaIKhls'
(Multiplexing technique)
• th Spread Spectum ix{d Ndú; lr.kS'
• mgka.efkkafka Data Signal Rate tllsks' ^o;a;
iïfma%IK fõ.hlsks'& th Dj,ska wr®: olajuq'
• ,efnk iEu bit tlla u w∞< md˙fNda.slhd f.a
≥rl:khg muKla wkkH jQ rgdjla jk Chips §k¶
m%udKhlg fnfoa' wms th Users code f,iska y∫kajuq'
w¨;a pek,fha Chip date rate tl §kD¶j,ska iukaú; h'
fï lshQ foh" W∞yrKhlska Tng meye†,s fõú'
k = 6" A, B, C hkqfjka md˙fNda.slhska ;sfofkls' A, B,
C hk ;sfokd u Base receiver, R iu. ikaksfõokfhka
iïnkaO fõ'
Code for A = < 1, -1, -1, 1, -1, 1 >
Code for B = < 1, 1, -1, -1, 1, 1 >
Code for C = < 1, 1, -1, 1, 1, -1 >
fyd|hs oeka my; ls%hdld˙;ajh fyd¢ka n,kak'
is;kak A" Base receiver (R) iu. ix{d yqjudre
lr.kafka h lshd' ta jf.a u A iy R hk fofokd u
m◊úv ^ix{d& yqjudrej ms<sn|j oek f.k isákjd
lshd o is;kak' (Assume Comumication already
synchroized)
• §ä‚g,a 1¶ Rg hjkakg A g wjYHhs" tneúkaA úiska
A f.a Code tl jk < 1"-1"-1" 1" -1" 1> Rg hefjhs'
(Sends A's chip pattern to R).
• §ä‚g,a 0¶ R hjkakg Ag wjYH kï" A úiska
< -1, 1, 1, -1,1, -1 > hk Chip pattern tl hefjhs' fuu
Chip pattern tl l,ska tflys Complement tl f,i
y∫kajuq' tkï l,ska A f.a bit rgdj ^-1&ka .=K l<
,efnk rgdjhs'
• Decoder tl A f.a Code mdúÉÑ lrk úg wfkla
≥rl:kj,ska (B fyda C) tk ix{d fkdi,ld y¯'
• R g ,enqKq Chip pattem tl A f.a Code tflka
.=K flfr®' tfia .=K lr ,efnk bit 6 tl;= l< úg 6la
,efí kï R fj; meñ◊fha ä‚g,a 1 nj R y∫kd.kS' ta
jf.au tu w.h -6la kï R fj; meñ◊fha ä‚g,a 0 nj
R y∫kd.kS'
my; igyka ks¯laIKh lrkak' fï lshQ foa Tng
fyd|g jegfyaú'
pek, 7 l CDMA moaO;shla Encoding yd Dewding
ls%hdj my; oelafõ'
f;jk hq.fha cx.u ≥rl:k
f;jk hq.fha cx.u ≥rl:k
f;jk hq.fha cx.u ≥rl:k
f;jk hq.fha cx.u ≥rl:k
f;jk hq.fha cx.u ≥rl:k
(3rd
Generation Mobile phones)
(Digital Voice and Date)
1992 ° ITU (International Telecommunication Union)
úiska IMT-2000 f,iska ixiohla msysgqjd .kafka f;jk
hq.fha cx.u ≥rl:k mrïmrdfõ wdrïNh iksgqyka lrñks'
IMT hkq International Mobile Telecommunication hkakhs'
§2000¶ u.ska yeÛjqfKa"
1' fuys fiajdjka md˙fNda.slhdg ,efnk jir
2' tys ls%hd;aul jk ixLHd;h MHzj,ska'
3' tys ls%hdld¯ mrdih (Bandwidth) kHzj,ska'
IMT-2000 cd,h wruqKq lr.;a m%Odk fiajdjka 4la
my; oelafõ' ^th bx.S%isfhka u i|yka lrkakï&'
1' High - quality voice transmission'
2' Messaging (Replacing e-mail, fax" SMS, Chat....)
3' Multimedia (Playing music , Viewing videos, Films, TV)
4' Internet Access
oeka" Tn okakd m˙† by; fiajdjka 4 u jr®;udk
cx.u ≥rl:k yryd wmg ,nd.; yels h' fndfyda úg
Tn Ndú; lrk ≥rl:kfha;a by; lS ,laIK ;sfnkjd
we;s' fï jk úg wms 3'5G ^3'5 Generation& hq.fha isáuq'
f;jk mrïmrdfõ cx.u ≥rl:kj, ,laIK
(Features) iM, lr.kakg m%Odk jYfhka fhdackd 2la
meñ◊fha h'
1' W-CDMA (Widebind CDMA)
2' UMTS ( Universal Mobile Telecommunication System)
fojk hq.fha wjidkfha ° yd f;jk hq.fha wdrïNfha
° Ndú; jk úfYaIs; ,laIKhka jkafka GPRS hkakhs'
(General Packet Radio Service)
(GPRS - An overlay Pocket network on top of D-AMPS or
GSMs. It allows mobile stations to send and receive IP
packets in a cell runing voice system.)
GPRSys ° tla tla ixLHd;j, ° ld,h fldgia lSmhlg
fnfoa' bka ld, fldgia lSmhla
Packet trafic i|yd fjka flfr®' fï ld, fldgia
(Time slots) .;slj md,kh (Dynamically managing) l<
yelafla (Base station tlg h' úúO ld, fldgia tla
tla ;dr®lsl fldgiaj,g (Logical Channels ) fnfok w;r
tu ;dr®lsl fldgia úúO fiajdjka i|yd fhd∞ .efka'
Base Station tl úiska l=uk ;dr®lsl fldgia l=uk ld,
fldgig wh;a oehs ksr®Kh lr .efkhs' tla ;dr®lsl
pek,hla (Logical channel) yd.; ls¯ï i|yd (Download)
fhd∞ .efkk w;r wka;r®cd,h yd Base tl w;r
we;af;a fN!;sl (wired connection ) iïnkaOhls'
GPRS .ek ;j≥rg;a ixlSr®Kj l;d l< yels uq;a
th Tng t;rï u jeo.;a fkd jkq we;' GPRS .ek
woyila ±ka Tng we;ehs is;ñ' fï ,smsfhka ≥rl:k cd,
ms<sn|j f.k wd ,sms fm< wjika fõ'
B<Û ,smsfhka wms m˙.Kl NdIdjla y∞ruq'
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy

14. 18
2010 uehs 19
ú≥y,
wms oeka n,uq fldfdydu o Struct type Pointer Variable tllg
Memory allocate lrkafka lshd'
uq,ska u Malloc.h hk header file tl include l< hq;=hs'
B<Ûg Pointer variablre tl (Struct type) wod< memory location
tllg assign l< hq;=hs'
ta i|yd WodyrKh - Size of Memory in bytes
emp1 = (Struct employee*) malloc (Size of (Struct empoyee));
fu;ek ° Struct type tlg memory location tl yrjd .ekSu is≥
fjhs'
jeo.;a -
jeo.;a -
jeo.;a -
jeo.;a -
jeo.;a - Structure Variable i|yd fuf,i wms u;lh fjka lrkafka
Structure tlla ;=< úúOdldr úp,H jr®. ;sìh yels ksid" ta ta
úp,H fjk fjk u access lr .; hq;= ksid;a h'
fyd|hs oeka wms my; Programs Type lr run lr n,uq' ta Program
kej; kej; n,d wOHhkfhys fhfokak
File handling in C
≤ka ud Tng lshd fokafka" fldfydu o File tlla
Read lrkafk;a fldfydu o File tllg Write
lrkafk;a lshk ldrKd'
- Reading data from files
- Writing data to files
wms WodyrKhlska u bf.k .ksuq'
m˙.Kl NdIdjla
bf.k .ksuq - 9
(C language)
by; Program tflka flfrkafka hï ;ekl we;s
File tlla ;sfhkjd o keoao hkak wmg oek.ekSug
ie,eiaùuhs' by; Program tl ;=< file tl ;sfhk
;ek yd tys ku Hard-Code lr we;'
jeo.;a - fopen () hk function tflka wod< file
tl open lrhs' tfyu file tlla ke;skï 'fp' pointer
tl Null fjhs'
u;l ;nd .kak' fp hk poirter tl
FILE type tflka declare lr we;s nj'
fp = fopen ("C:MyProgtest.txt" , "r") ;
file extension tl
file tl ;sfnk ;ek iu. tys ku
fopen kue;s function tfla fldudfjka ol=Kqmi
wms file tl open lrkafka read lrkakg o write
lrkakg o hk j. "r" yd "w" u.ska ikd: lruq' w+
f,i fh≥fjd;a Write lrkak;a read lrkak;a mqΩjks'
test kue;s text file tl ;sfnk ;ek ú†yg "C"
drive tfla "My prog" kue;s folder tl ,nd ° we;'
oeka wms l,ska program tl jeä †hqKq lruq'
user input lrk ´kE u file kduhla search lr th
;sfnkjd o ke;a o lshd lSug' fuys ° user úiska
wod< folder path tl yd extension tl †h hq;=hs&
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy
;˙∫ ùrisxy

15. 21
ú≥y,
2010 uehs 19
ú≥ir
ú≥ir
ú≥ir
ú≥ir
ú≥ir f.k tk fuu ,sms fm<ska wm woyia lrkqfha"
m˙.Kl yd ne∫Kq úúO úIh fCIa;% flfrys ir,
wjfndaOhla Tng ,nd °uhs' m%:ufhka wms" m˙.Klhla
l%shd;aul jkafka flfia oehs ir,j wOHhkhla lruq'
How Computers Wark?
m˙.Klhla hkq" ñksia Wmfoiaj,g wkqj l%ñlj
l%shd;aul úh yels" .◊;uh yd ;r®ldkql+, l%ufõohkag
wkqj m%;sM,hla ,nd †h yels úoHq;a WmlrKhla' jr®;udk
f,dalfha m˙.Kl yd m˙.Kl Ñm fkdue;s WmlrKhla
fidhd .ekSug;a wmyiq ;rug u ;dCIKh †hqKq ù
;sfnkjd''''''''''
wo Ndú; jk fndfyda m˙.Klj, Ndú; jkafka Von
Neumann wdlD;shhs' (Neumann keue;s úoHd{hd úiska
y∫kajd ≥ka wdlD;sh& tu wdlD;shg wkqj m˙.Klh
m%Odk fldgia 4 lska iukaú;hs'
∗ .◊;uh yd ;r®ldkql+, fldgi
(Arithmetic Logic Unit - ALU)
∗ md,l fldgi (Control Circuitry)
∗ u;lh (Memory)
∗ ,nd.ekSfï yd m%;sM, ,nd°fï fldgia
(Input-Out put devices)
my; rEmigykska Von-Neumauu wdlD;sh .ek Tng
fyd| woyila ,nd.; yelshs'
Von-Neumanu wdlD;sfhka y∫kajd fok m%Odk fldgia
4" tlsfklg iïnkaO jkqfha BUSES keue;s l=vd ;U
jhr rdYshla tl;=fjka iE≥Kq iïnkaO; jdysks BUSES
md,kh jkafka tlafldA TIMER tlla u.ska fyda CLOCK
tlla u.sks' ^ld,.Klhla fyda Trf,daiqjla&
Processor (CPU) Central Proessing Unit)
Processor tl iE° ;sfnkafka ALU yd CU tflks'
(Arithmetic Logic unit & Control unit) Processor tl"
m˙.Klfha fud<h hs'
ALU m˙.Kl u.ska flfrk ishÆu .◊;uh yd ;r®luh
l%shdjka fuhska is≥ fjhs'
Arithmetic Opertions - Addition, Substraction, Multi-
plication 4 Division
Logical Opertions - AND, OR, NOT & Comparing
opertions
CU (Control Unit)
Processor tfla md,l fldgi fukñka ye¢kafjhs'
tu.ska m˙.Klh úiska tla úfgl ° l%shd;aul lrjk
Wmfoia wvx.= u;l fldgi ms<sn| o;a; ;ndf.k isák
w;r u ALU tlg l=uk Wmfoia mo l%shd;aul l< hq;= o
hkak;a lshd fokjd' tajf.a u tu Wmfoia u;lfha (RAM)
l=uk fldgiska ,nd.; hq;= o hkak;a lshd fokjd' Bg
wu;rj tla Wmfoia l%shd;aul jq miq (After an opertion)
tys m%;sM,h kej; u;lfha
r|jkjd' (Transfers the result
back to the appropriate meory
location) bkamiq B<Û Wmfoia
mo;a l%shdjg kexùu wdrïN
lrkafka fuu Control Unit tlhs'
CPU tll wx.j, o< igyka
my; olajd we;'
m˙.Kl f,dj .ek
m˙.Kl f,dj .ek
m˙.Kl f,dj .ek
m˙.Kl f,dj .ek
m˙.Kl f,dj .ek
ir,j oek.ksuq
ir,j oek.ksuq
ir,j oek.ksuq
ir,j oek.ksuq
ir,j oek.ksuq
m˙.Kl f,dj .ek
m˙.Kl f,dj .ek
m˙.Kl f,dj .ek
m˙.Kl f,dj .ek
m˙.Kl f,dj .ek
ir,j oek.ksuq
ir,j oek.ksuq
ir,j oek.ksuq
ir,j oek.ksuq
ir,j oek.ksuq
Processor
(CPU)
}
Memory
m˙.Kl u;lh wms Computer Memory f,i
y∫kajkjd' l%ñlj ;, úoHq;a wxlkfhka ie≥ï,;a l=vd
ix.Dys; m˙m:j,ska ;ekqKq Cells, m˙.Kl u;lh f,ig
wms y∫kajkjd' tu Cells o;a; (information) /ila r|jd
;nd .kakjd' fuu o;a; m˙.Klhg iemfhk Wmfoia
mo úh yels w;r u m˙.Klh ;=< ;djld,slj r|jd
;nd .kakd Wmfoia mo l%shd;aul úh hq;= wkqms<sfj,j,a
o úh yels h' m˙.Kl u;lh wms Random Access
Memory (RAM) f,i y∫kajkjd' m%Odk jYfhka fuh
fldgia 2 lska hqla;hs'
1
1
1
1
1. Static RAM ^ia:ß;sl u;lh&
^ia:ß;sl u;lh&
^ia:ß;sl u;lh&
^ia:ß;sl u;lh&
^ia:ß;sl u;lh&
g%dkaisiagr (Transistors) 4 la" 6 la fhdod f.k ;efkk
fuu u;lh (Static RAM cells) r|jd .kafka ;ks bit
tfla o;a;hs' (Single bit of data) CPU (Processor) tll
wNHka;r u;lh tkï Cache or register, fuu Static
RAM .Khg whs;shs' Static RAM; ksmoùug ;rula
wêl ms˙jehla orkakg is≥jkjd' Static RAM tl
jeämqr Ndú;d jkafka CPU tfla L2 Cache tl ;=<
h' my; oelafjkafka Static RAM tll m˙m: igykls'
;˙≥ ùrisxy
;˙≥ ùrisxy
;˙≥ ùrisxy
;˙≥ ùrisxy
;˙≥ ùrisxy