Jun 29, 2015

Computer Network - Lesson 04

http://www.aluth.com/2015/06/computer-network-lesson-04.html
f;afrk isxyf,ka mß.Kl fkÜj¾lska 04 fjks mdvu¡

wlKavj Tnfj; f.k wd fuu mdvï ud,jg w¨;a fjí wvúfha risl msßia fndfydauhla wmfj; Bfï,a lsÍfuka ia;+;shs iy lD;{;dj m,lr isáhd¡

b;ska Tkak ;j;a mud fkdlr wo 04 fjks mdvu n,uq¡
  • o;a; iïfma%IKh wdldr
o;a; iïfma%IKh jk wdldr my; f,i j¾. lr oelaúh yel'
  1. Band width of transmission
  2. Serial and Parallel transmission
  3. Direction of transmission
  4. Mode of transmission
  5. Protocols


 1. Band width of transmission 

ta ta udOHfha o;a; iïfma%Ik fõ.h" ;rx. mrdih keue;s ixl,amh u.ska m%ldY lrkq ,efí' tu o;a; .uka lsÍfï fõ.h ;;amrhg bytes j,ska ukskq ,efí'f ï jkúg ;rx. mrdi 3la Ndú;d fõ'

  • Voice band
  • Medium band
  • Broadband

- Voice band

idudkH ÿrl:k moao;s ioyd Ndú;d lrkq ,nk twisted pair udOHh fï ioyd Ndú;d lrhs' fï ioyd fõ. iSudj 110 bps ( byte per second ) 9600 bps w;r mj;S'

- Medium band
,Sia ,hska fyj;a Dedicated udOHh Ndú;d flf¾' fï ioyd wod, fõ. mrdih 9600 bps - 256000 bps w;r fõ'

- Broadband
fuys o;a; iïfma%Ik fõ.h 256000 bps-1000000 bps mrdihl mj;S' tys  udOHla f,i coaxial cable, fiber optic, microwaves, satellite oelaúh yelsh'




  2. Serial and parallel transmission  


mß.Kl wdOdrfhka o;a; iïfma%Ikh ioyd serial fyda parallel port Ndú;d lsÍug mq¿jk serial port tl parallel port tlg jvd fõ.j;a fõ' mß.Kl cd, weiqfrka o;a; yqjudre lsÍu ioyd idudkHfhka serial port Ndú;d lrhs'


  3.Direction of transmission    ^úldYk ÈYdj&

o;a; iïfma%IkfhaÈ o;a; .,k ÈYdj b;d jeo.;a fõ' fuh ixl,am 3la u; mokï ù we;'

  • Simplex communication ^talm;a ixksfõokh&
  • Half duplex communication ^w¾O oaõm;a ixksfõokh&
  • Full duplex communication ^mQ¾K oaõm;a ixksfõokh&

- Simplex communication

 
fuu l%ufhaÈ f;dr;=re tla ÈYdjlg muKla .uka lrhs'o;a; ixksfõokfhaÈ fuh b;d wvqfjka Ndú;d fõ'







- Half duplex communication


fuu l%ufhaÈ f;dr;=re fome;a;gu .,d hd yels w;r tlu fõ,dfõÈ tfia isÿ fkdfõ' fï ioyd WodyrK f,i idudkHh ÿrl:k /yeka Ndú;d lr mß.Kl 2la iïnkaO lsÍu oelaúh yel' fujeks wjia:djl isÿjkafka tlajrl§ o;a; tlaÈYdjlg muKla .,d hEuhs'


Wod - fjdals fgdals




- Full duplex communication

fuu l%uh b;d ÈhqKq l%uhla jk w;r tlu fõ,dfõÈ fome;a;gu f;dr;=re .,d hhs' fï ioyd ñ, wêl WmlrK Ndú;d fõ'



  4. Mode of transmission   ^úldYk wdldrh&

hï lsis ld,hla ;=<§ yqjudre lr.kakd f;dr;=re j, m%udKh b;d jeo.;a fõ' fï ioyd ixl,am 2la we;'

  • Asynchronous transmission
  • Synchronous transmission

- Asynchronous transmission

fuu l%ufhaÈ jrlg Bit 1l o;a; heùu fyda ,nd.ekSu isÿ lrhs' fõ.h b;du;a wvq WmlrK j,ska o;a; iïfma%Ikh lsÍfïÈ fuu l%uh Ndú;d flf¾' hjkakdg myiq fõ,djl§ f;dr;=re heùu l< yels ùu fuu l%ufha jdishls'key board yd Serial port u.ska o;a; yqjudrej fï ioyd WodyrK fõ'

- Synchronous transmission
fuu l%ufhaÈ msgq iuQyhla Block tlla fia o;a; heùu fyda ,n.ekSu isÿ l< yel' fuu l%uh Ndú;d lrkq ,nk moaO;s j, f;dr;=re heùu fyda ,nd.ekSu iqÿiq f,i ld,h mejÍfuka yd ie,iqï iy.;j isÿ l, yel'


  5. Protocols   
mß.Kl w;r o;a; iïfma%Ikhg fhdod .kq ,nk kS;sÍ;S iuQyh protocols f,i yeÈkafõ' fuh ,efnkqfha computer programme tlla f,ih' b;du ckm%sh protocol tlla f,i TCP yd IP yeÈkafõ' ^ Transmission control protocols $ internet protocols & úfYaIfhka fuh wka;¾cd, lghq;= i|yd Ndú;d fõ'

wka;¾cd, iïnkaO;djh fkdue;s LAN tll§ jqjo TCP yd IP fhdod.; yelsh' fufyhqï moaO;sh wOdrfhka mß.Kl w;r TCP yd IP u.ska yqjudre lsÍu ioyd fuh Ndú;d fõ' Network card Tiafia cd, ieliSu ioyd wksjdrHfhkau protocol tlla ‍wjYHh jk w;r Protocol lsysmhla Network card tllska yeisrùuo l< yelsh'



- Modem

Modem tflys m%Odk ldrHh jkqfha Yío ix{d ixLHdxl ix{d njg m;a lsÍu;a ixLHdxl ix{d Yío ix{d njg m;a lsÍu;ah' we;eï mß.Kl moaO;s j, yqjudrejg Network card fhdod .;a;o ÿrl:k moaO;s yd iïnkaO ù cd,;ekSfïÈ Network card Ndú;d l< fkdyelsh' thg uQ,sl fya;=j jkqfha ÿrl:k /yeka j, .uka lrkqfha Analog signal h'

fuu analog signal , Digital fyj;a 0"1 hk udOHfha o;a; yqjudre lrk mß.Klhg f;areï .; fkdyelsh' tu ksid wod, ldrHh isÿ lr.ekSug Modem Ndú;d lrhs' Modem hkq Modulator yd Demodulator hkak flá lr oelaùuls'


;;amrhg heúh yels Bites m%udKh o;a; yqjudre lrk fõ.h uekSu ms,sn| uQ,sl ixl,amhla fõ' 1200 bps" 2400bps" 9600bps" 14400bps" 28800bps" 33600bps hk fõ. iys; Modem wo ,n.; yelsh' Modem tflys o;a; ixksfõok fõ.hg iudkj ixksfõok udOHh i;= fõ.ho n,mdkq ,nhs'

Modem
j¾.¡
- Internal modem
- External modem
- Wireless modem





fuu fudvï j¾. .ek wms 05 fjks mdvfuka tlska tl jeäÿr f;dr;=re oek.uq¡ miq.sh mdvï n,mq ke;s wh my;ska msúi n,kak¡



 
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