M HNH OSI (Lin kt ni cc h thng m)Open Systems Interconnection Reference Model, vit ngn lOSI ModelhocOSI Reference Model) - tm dch lM hnh tham chiu kt ni cc h thng m Host l 1 thc th mng c kh nng truyn c cc ng dng. (PC-Computer) M hnh OSI

Ti sao phi s dng m hnh phn lp: Reduces complexity : Gim thiu c phc tp ca cc h thng truyn d liu, trong sn xut thit b. Standardizies interfaces : Chun ha cc giao din ca cc dng sn phm. m bo tnh tng thch v mt cng ngh ( thit b ca hng khc nhau c th giao tip vi nhau ). Facilitates modular engineering: Thc y k thut Modul ha.

Thc y s pht trin ca ngnh cng ngh mng. n gin cho vic dy v hc.

1. Lp Physical ( vt l ): Truyn 1 dng bit qua 1 ng truyn vt l no , v duy tr kt ni (dng in, dy mng, s thy dc) => xy dng c 1 ng truyn vt l cho cc HOST.Quy nh cc c im ca ng truyn vt l c, in, quang cc th tc chc nng truyn mt dng bt nh phn qua ng truyn vt l, Xy dng ng truyn vt l qua cc hostVd: Bt 1 l 5v - bt 0 l 0v2. Lp DataLink (Lin kt d liu ):

iu khin vic truy nhp d liu vo ng truyn vt l Cung cp c ch d li. Giao tip vi lp mng (Network) bn trn n.

**** nh dng d liu, ng khung d liu, cu trc ha d liu & a ra cc c ch iu tit d liu t lp Data Link & cc lp trn c th truy nhp & write vo ng truyn vt l ****

3. Lp Network (Mng):

Phn b d liu 1 cch ti u nht. nh tuyn ( routes) gia cc gi d liu, chn ra ng i ti iu nht phn phi d liu. nh ngha ra cc giao thc ( giao thc gi l nh tuyn ) a ch logic ( a ch IP )

4. Lp Transport (Giao vn):

Qun l cc kt ni u cui End to End . S l cc vn truyn dn gia cc HOST, m bo rng d liu c truyn 1 cch ng tin cy trong mng. m bo thit lp, duy tr v gii phng cc ng mch o.Rcmd Cung cp cc c ch sa li tin cy, d li tin cy v phc hi thng tin bng cch iu khin lung.

5. Lp Session (Phin):

cc ng dng 6,7 c th truy nhp vo ng truynThit lp, qun l v gii phng cc session ca ng dng (t chc cc phin kt ni, phn bit cc ng dng), phn bit ng dng v cc ng dng khc nhau.

6. Lp Presentation (Trnh by):Vn : Cha chc d liu ny truyn m u kia c th hiu c ?Khi Lp Presentatiom s nh mt ngi Thng Ngn: T chc li d liu Cu trc li d liu Thng lng cc c php truyn d liu cho tng ng dng Cung cp c ch m ha

7. Lp Application (ng dng):

Giao tip trc tip vi ngi dng Cung cp cc ng dng mng , cc dch mng cho tng ng dng ( mail, chuyn file, truy nhp t xa..) Cung cp c ch xc thc ngi dng ( user name , pass..)

Tin trnh ng gi d li ti u gi:Header : (tiu ) vit tt l HDR

Ban u Sender gi 1 User Data xung Application. Vi mi tng User data s c gn thm cc HDR ca tng . Ton b gi tin lp trn s l d liu ca gi tin lp diRing n lp 2 th bc thm kim tra li FCS .Sau khi n tng Physical th User Data c chuyn thnh cc bits ri di chuyn n ngi nhn.Bn u nhn d liu th tin trnh c din ra ngc li vi u gi.

Tin trnh truyn thng ngang hng:

n v d liu ca lp Transport l Segmentsn v d liu ca lp Network l Packetsn v d liu ca lp Data Link l Framesn v d liu ca lp Physical l Bits

M HNH TCP/IP

So snh gia hai m hnh: