Mang & truyen du lieu -HCN TPHCM.PDF

Trng ai Hoc Cong Nghiep Tp. Ho Ch Minh

Giao trnh Mang va Truyen d lieu. 1

KHAI NIEM C BAN VE MANG

I. CAC KHAI NIEN C BAN. - Mang may tnh la gi : Mang may tnh la 1 nhom cac may tnh,

thiet b ngoai vi c noi ket vi nhau thong qua cac phng tien truyen truyen dan nh cap, song ien t, tia hong ngoai..giup cho cac thiet b nay co the trao oi d lieu vi nhau 1 cach de dang. - Cac thanh phan c ban cau thanh mang may tnh :

+ May tnh : May tnh s dung trong mang bao gom cac loai may Mainframe, minicomputer, Laptop, Personal Computer..moi thanh phan nay la 1 iem noi vat ly lien ket tren mang.

+ Cac thiet b giao tiep dung lien ket cac thanh phan mang : Card mang ( NIC hay adapter ), HUB, SWITCH, ROUTER.

+ Moi trng truyen dan : hu tuyen ( cap ), vo tuyen ( song ien t, tia hong ngoai )

+ Cac thiet b ngoai vi : May PRINTER, FAX, MODEM, SCANER + Cac giao thc ( TCP/IP, IPX/SPX, NetBeui.) + Cac he ieu hanh mang : WinNT, Novell Netware, Unix.

- Cac thuat ng lien quan : + Server : La may phuc vu c cai at he ieu hanh va cac phan

mem chuyen dung lam cac chc nang quan ly va cung cap cac dch vu cho cac may tnh khac. Tuy theo dch vu cung cap ma ngi ta chia ra lam cac loai server sau: File server : dung cung cap cac dch vu ve file va folder. Print Server : Cung cap cac dch vu ve in an.. Do cac may server lam chc nang phuc vu nen cau hnh may server phai manh thng la cac may chuyen dung cua cac hang nh Intel, IBM..

+ Client : La may s dung cac dch vu ma may server cung cap. Do s ly cong viec khong ln nen thong thng cac may nay khong yeu cau cau hnh manh.

+ Host : Host la 1 diem noi tren mang. Host co the la client hay server.

+ Resource : La nhng tai nguyen tren mang gom : tap tin, th muc, may in, may Fax..



+ Share data : la tap hp cac tap tin, th muc ma cac may tnh chia se e cac may khac truy cap s dung chung thong qua mang.

+ User : la tai khoan ngi dung khi s dung may tram( client ) e truy xuat en nhng tai nguyen mang. Thong thng 1 user se co 1 username va password do nha quan tr cung cap, he thong se da vao username va password e nhan biet ban la ai va co quyen hay khong co quyen vao mang, co quyen hay khong co quyen s dung tai nguyen tren mang.

+ Administrator : La tai khoan quan tr he thong. + Phng thc gi d lieu tren he thong mang : D lieu c gi t iem nay en iem khac trong mot bo phan nho goi la: goi, khung hoac o d lieu (ATM). Goi c xac nh bang ngon ng hoac giao thc c dung trong mang.

Header Data Footer II. MO HNH MANG MAY TNH Mang tap trung : Toan bo tien trnh x ly tai may tnh trung tam. Cac

may tnh tram cuoi ( terminal ) c noi mang vi may tnh trung tam va hoat ongn nh nhng thiet b xuat nhap d lieu cho phep ngi dung ch xem tren man hnh va nhap d lieu t ban phm. Mo hnh x ly mang tren co the trien khai tren he thong phan cng hoac phan mem c cai tren server u iem : D lieu c bao mat an toan, de dang backup va diet virus, chi ph cho cac theit b thiet lap mang thap. Nhc iem : Kho ap ng cac yeu cau cua nhieu ng dung khac nhau, toc o truy xuat cham.



Mang phan tan : Cac may tnh co kha nang hoat ong oc lap, cac cong viec c tach nho va giao cho nhieu loai may tnh khac nhau x ly thay v x ly tai may tnh trung tam. Tuy d lieu c x ly va lu tr tai cac ,may cuc bo nhng chung c noi mang vi nhau nen chung co the trao oi d lieu va dch vu.

u iem : Truy xuat nhanh, phan ln khong gii han cac ng dung Nhc iem : D lieu lu tr ri rac kho ong bo, backup va rat de nhiem virus.

Mang cong tac : Gom nhieu may tnh co the tng tac vi nhau e thc hien 1 cong viec. 1 may tnh co the mn nang lc cua may khac bang cach chay chng trnh tren may khac nam trong mang.



u iem : Rat nhanh va manh, co the chay cac ng dung co cac phep toan ln. Nhc iem : Cac d lieu lu tr tren cac v tr khac nhau nen rat kho ong bo va backup, kha nang nhiem virus rat cao.

III. CAC LOAI MANG MAY TNH. Mang cuc bo LAN ( Local Area Network )

Mang LAN c xay dng tren c s gom 1 nhom cac may tnh va thiet b truyen thong c noi vi nhau trong 1 pham vi nho. ( trng hoc, nha cao oc.) Mang LAN thng co cac ac iem sau: + Bang thong ln, Truyen tai d lieu vi toc o cao. + Ton tai trong 1 pham vi hep, kch thc b gii han. + Chi ph cho cac thiet b ket noi mang LAN tng oi re. + Cong viec quan tr mang n gian, de dang.

Mand dien rong WAN ( Wide Area Network )

Mang WAN c xay dng tren c s nh 1 mang c bao phu 1 vung a ly rong ln co the la 1 quoc gia, 1 chau luc hay toan cau. Mang WAN thng c cac cong ty a quoc gia xay dng. Do pham vi mang rong ln nen thong thng WAN la tap hp bi nhng mang LAN noi lai vi nhau thong qua cac thiet b truyen thong : ve tinh, song viba, cap quang, cap ien thoai.. Mang WAN thng co ac iem sau : + Bang thong nho, truyen tai d lieu vi toc o thap. De b mat ket noi thng ch phu hp vi cac ng dung nh Email, Web, ftp. + Ton tai trong pham vi rong, kch thc khong b gii han.



+ Chi ph cho viec xay dng Wan rat at tien. + Do ket noi nhieu LAN nen mang rat phc tap va co tnh toan cau

nen phai co to chc quoc te ng ra qui ng va quan tr. Internet : internet la mang may tnh ln nhat the gii hoac chnh xac

hn la mang cua cac mang tc la bao gom rat nhieu .nhieu nhng may tnh noi lai vi nhau. No cho phep bat ky 1 may tnh nao trong mang co the ket noi vi bat ky may nao khac tren mang va trao oi thong tin vi nhau. 1 khi ket noi vao internet may tnh cua ban se la 1 trong hang chuc trieu thanh vien cua mang khong lo nay.

IV. MO HNH QUAN TR MANG + Workgroup : Trong mo hnh nay cac may tnh co quyen han ngang nhau va khong co cac may chuyen dung lam nhiemvu cung cap dch vu hay quan ly dch vu. Cac may tnh lam viec che o workgroup t bao mat va quan ly tai nguyen cua rieng mnh ong thi no cung chng thc cho ngi dung cuc bo + Domain : trong mo hnh nay trong he thong co cac may tnh chuyen dung lam nhiem vu cung cap cac dch vu, quan ly va chng thc ngi dung, quan ly cac may tram. Cac tai nguyen cung c quan ly va cap quyen han cho ngi tng ngi dung. V. CAC KIEU NOI MANG :



+ Peer to Peer ( Mang ngang hang ) - Mang ngang hang bao gom 1 nhom cac may tnh c ket noi vi nhau, lam viec cung vi nhau. - Tat ca cac may trong mang eu co quyen nh nhau, khong co bat ky 1 may tnh nao ong vai tro phuc vu. Ngi dung tren tng may chu trach nhiem ieu hanh, quan ly va chia se cac tai nguyen cua chnh may tnh mnh s dung. - Lam viec tot vi cau hnh mang t hn 10 may.

u iem : n gian, de dang cai at, to chc va quan tr, chi ph thiet b dung thiet lap mang thap

Khuyet iem : khong quan ly tap trung nen d lieu phan tan. Kha nang bao ve rat thap, rat de b xam nhap.

+ Client / Server ( Mang khach / chu ) - Mang Client / Server bao gom 1 nhom may phuc vu cung cap cac tai nguyen va dch vu cho ca he thong mang s dung goi la he thong may chu (server). Mot he thong gom nhieu may tnh s dung cac tai nguyen va dch vu do he thong may chu cung cap goi la may khach (Client). - Tai khoan ngi dung (USER) do may chu cung cap va c quan ly bi may chu. Ch may chu mi co quyen giai quyet cac yeu cau cua USER. - Cac may server thng co cau hnh manh ( toc o x ly nhanh, khong gian lu tr ln) thng s dung cac may tnh chuyen dung. - Da vao chc nang ta co the chia he thong SERVER ra thanh cac loai server nh sau : + File server : Cung cap dch vu phuc vu cac yeu cau ve file trong mang + Print server : Cung cap cac dch vu ve in an + Application server : Cung cap cac dch vu cho phep cac ng dung chay tr6en server va tra ket qua ve cho client. + Mail server : Cung cap cac dch vu ve gi va nhan MAIL + Web server : Cung cap cac dch vu ve WEB + Database server : Cung cap cac dch vu ve lu tr, tm kiem thong tin + Communication server : Quan ly cac ket noi t xa. u iem : D lieu c lu tr tap trung, de dang backup va ong bo vi nhau. Tai nguyen va dch vu tap trung nen de chia se quan ly va phuc vu cho nhieu ngi dung. Kha nang bao mat d lieu cao, theo nhieu lp.



Khuyet iem : Cac server chuyen dung at tien va phai co oi ngu quan tr he thong mang. VI. CAC DCH VU MANG Dich vu mang la ly do tai sao chung ta s dung he thong mang. phan nay mo ta cac hau het cac dch vu trong he thong mang. + C s e lien ket cac dch vu mang : Tat ca cac PC trong mang phai c cai at he ieu hanh va he thong phan mem chuyen dung cho phep chung lam viec c vi nhau trong moi trng mang.

+ Redirector service : redirector la 1 chng trnh chay tren may tram lam viec kiem soat nhng yeu cau lien quan en mang. Chang han 1 ngi dung tren tram lam viec yeu cau cac tap tin noi bo th Redirector se chuyen nhng yeu cau o en HH noi bo. Neu yeu cau o nham vao nhng tap tin may tnh khac tren mang th Redirector se kiem tra cac yeu cau va sau o gi cac yeu cau chuyen tiep qua mang e en ch thong qua 1 ng truyen nh san. - Yeu cau c at trong 1 goi tin co a ch tram dch vu. - Phan mem Redirector c cai at rieng moi tram lam viec cung vi phan mem ieu khien crad mang.

+ Server service : May tnh server phai co nhng thanh phan tiep nhan nhng yeu cau t cac client trong mang va thc hien nh tuyen hoi ap nhng yeu cau thong qua he thong mang ti cac client. file service :

+ file service cho phep cac may tnh mang chia se file, thao tac tren cac tap tin nay nh : lu tr, tm kiem, di chuyen.. + file service cho phep user : oc, viet, quan ly file va data. + file service rat quan trong oi vi mang kieu noi mang client/server va peer to peer. + May tnh cung cap cac dch vu ve file goi la file server. Co 2 kieu file server : Chuyen dung va khong chuyen dung.

- File server chuyen dung thng dung trong mang kieu client/server va ch lam 1 nhiem vu duy nhat ap ng tat ca cac yeu cau t client trong mang.

- File server khong chuyen dung thng s dung trong mang kieu peer to peer no lam 1 luc 2 nhiem vu. Cho phep may tnh va ong vai tro la file server ap ng tat ca cac yeu cau t cac may tnh khac trong mang va ong vai tro la user yeu cau s dung file t file server khac.



File transfer service : + Dch vu truyen tai tap tin : Cho phep truyen tai file, data t ni nay sang ni khac nhanh chong de dang. Gia s co 1 tap tin hay tai lieu muon di chuyen t v tr nay sang v tr khac th ta co cac giai phap thc hien la :

- Dung o a di dong e sao chep, di chuyen d lieu.( Kho khan khi di chuyen d lieu en nhng ni xa. - S dung ket noi dial up e ket noi 2 may tnh lai va sao chep, di chuyen d lieu gia chung( toc o ng truyen qua cham, sao chep va di chuyen d lieu lau). - Trong ca 2 giai phap tren th eu co nhng nhc iem rat ln. Do

vay neu co mang va s dung dch vu truyen tai file se cho chung ta kha nang truyen tai d lieu de dang vi toc o cao. + Hau het cac he thong mang eu co 1 vai trung tam lu tr file e lu tr nhng file quan trong trong nhieu nam. File, data thng c lu tr theo cac cach sau : - Lu tr trc tuyen (online storage) : D lieu c lu tr trong a cng nen truy xuat de dang nhanh chong bat ke thi gian. Nhng phng phap nay co 1 nhc iem la chung khong the thao ri e trao oi hoac lu tr tach ri ong thi chi ph cho 1 MB d lieu online tng o cao. - Lu tr ngoai tuyen (offline storage) : Thng ap dung cho nhng d lieu t khi can truy xuat. Cac thiet b pho bien dun cho phng phap nay la Bang t va a quang. Phng phap nay khi truy xuat kha cham. - Lu tr can tuyen (Near-line storage): Thng dung thiet b jukebox e t ong quan ly cac bang t, a quang. Cho toc o truy xuat nhanh hn lu tr ngoai tuyen nhng chi ph khong cao. + Chuyen di d lieu (data migration) : La cong nghe t ong di cac d lieu t dung t kho lu tr trc tuyen sang kho lu tr can tuyen hay ngoai tuyen. Noi cach khac la qua trnh chuyen cac file, data t dang lu tr nay sang dang lu tr khac.



+ Sao lu d phong (File archive) : La qua trnh sao chep va lu tr 1 ban sao d lieu t thet b lu tr chnh. Khi thet b lu tr chnh co s co th chung ta dung dung ban sao d phong e phuc hoi lai d lieu. + ong bo hoa viec cap nhat d lieu (File-update Synchronization) : Theo doi cac thay oi khac nhau len cung 1 tap tin, e am bao rang tat ca moi ngi dung eu co ban sao mi nhat cua tap tin va tap tin khong b hong.

Printer service : Dch vu in an la 1 ng dung mang ieu khien va quan ly viec s dung cac may in trong mang. Cac li ch cua dch vu in an : - Nhieu ngi cung s dung chung may PRINTER lam giam chi ph. - May in co the at tai bat ky ni au trong he thong mang. - Dung c che hang i in cho phep an nh mc o u tien cua cac tai lieu can in.

Application service :



Dch vu nay cho phep cac ng dung co the huy ong nang lc cua cac may tnh chuyen dung khac tren mang. VD : Khi may client thc hien 1 phep toan can kha nang x ly manh. No s dung nang lc cua may chuyen dung khac tren mang x ly phep toan cho no roi tra ket qua ve lai cho client.

Database service :

Dch vu c s d lieu cho phep cac ng dung c thiet ke chay ng dung tai client va c s d lieu c lu tr, quan ly bi server. Dch vu c s d lieu thc hien cac chc nang sau :

- Bao mat c s d lieu. - Toi u hoa tien trnh thc hien cac tac vu c s d lieu. - Xac nh v tr tot nhat e lu tr d lieu (khong bat buoc client phai biet vi tr cua d lieu). - Phuc vu so lng ngi dung ln, truy cap nhanh vao c s d lieu. - Phan phoi d lieu qua nhieu he phuc vu c s d lieu.

+ Cac phng phap cap nhat d lieu sao lu d phong - Master-driven updates : May phuc vu chnh nhan tat ca nhng thong tin cap nhat va khi he thong m no cap nhat tat ca nhng thong tin mi len ban lu tr d phong trc o. - Locally driven updates : Bat ky v tr may phuc vu nao nhan c ban cap nhat mi nhat va no chu trach nhiem phan phoi s thay oi en nhng ban lu tr d phong trc o.



Message / Communication service :

La dch vu cho phep gi va nhan thong tin t ni nay sang ni khac. Thong thng bao gom 3 dang sau : Mail, Voicemail, Fax Mail : La he thong th ien t cho phep gi va nhan trong LAN hay nhan thong qua internet.

- 1 so he thong Email phc tap co ho tr them ve sound, graphics va videoe2

- 1 vai loai Email server chyen nghiep : Microsoft Exchange Server, Novells Group Wise, Lotus Notes. Voice mail : Cho phep ket noi may tnh en he thong ien thoai va nha cung cap cac dch vu ve truyen cac ban tin nhan dang tieng thong qua may tnh. No ket hp he thong truyen tieng noi tren may tnh vi tieng noi tao ra voice mail truyen en may tnh khac thong qua mang. Fax service : Cho phep gi nhan FAX thong qua he thong mang. Thong thng may FAX trong he thong mang c quan ly bi fax serve[r.

Diectory service : Dch vu nay cho phep tch hp moi thong tin ve cac oi tng tren mang thanh 1 cau truc dang th muc dung chung nh o ma qua trnh quan ly va chia se tai nguyen tr nen hieu qua hn.

Sercurity service : Bao mat la 1 van e het sc quan trong trong he thong mang. Thong thng viec bao mat tai nguyen va d lieu cho toan he thong mang co the do ngi quan tr mang hay chnh ngi chu cua d lieu quan ly bang cach ap chnh sach truy xuat cho tng ngi dung hoac tng nhom ngi dung tren mang.



V du : Khi ban chia xe tai nguyen hay d lieu tren he thong mang ban co quyen ieu khien hoac ch nh nhng ai co quyen truy xuat en tai nguyen o va lam c cai g vi no.



MO HNH THAM CHIEU OSI I. CAC TO CHC NH CHUAN VA ISO + ITU ( International Telecommunication Union ) : Hiep hoi vien thong quoc te + IEEE ( Institute of Electronic and Electronic Engeneers ) : Vien cac ky s ien ien t + ISO ( International Standard Organization ) : To chc tieu cuan quoc te, tru s tai Genever, Thuy S. Vao nam 1977, ISO c giao nhiem vu thiet ke 1 chuan truyen thong da tren ly tuyet ve kien truc he thong m lam c s e thiet ke mang may tnh. Mo hnh nay co ten OSI ( Open System Interconnection : Tng ket cac he thong m ) II. QUI LUAT VA QUA TRNH THONG TIN : Truyen thong tren mang rat giong thong tin gia con ngi vi nhau phai co nhng qui luat e ngi nay co the noi chuyen vi ngi khac. Mang may tnh that s co rat nhieu qui luat e trao oi thong tin. 1 vai qui trnh c quan ly bi nhng tieu chuan cua mang la : + Nhng qui trnh dung e thiet lap va ket thuc qua trnh thong tin. + Nhng tn hieu dung mieu ta d lieu trong moi trng truyen thong. + Nhng kieu cua tn hieu s dung. + Nhng phng phap truyen tn hieu thong qua moi trng truyen thong. + Nhng phng phap s dung e nh hng ban tin en ch nh trc. + Nhng qui trnh dung ieu khien toc o cua dong chay d lieu. + Nhng phng phap cho phep cac loai may tnh khac nhau thong tin vi nhau. + Nhng ng i e bao am ban tin a c nhan la chnh xac. III. MO HNH THAM CHIEU OSI Vao nam 1978 ISO ban hanh tap hp ac iem ky thuat mo ta kien truc mang danh cho viec ket noi nhng thiet b mang khong cung chung loai. Nam 1984 ISO phat hanh ban sa oi mo hnh nay va goi la mo hnh tham chieu OSI. Ban sa oi nam 1884 tr thanh tieu chuan quoc te va c dung nh hng dan mang. Mo hnh OSI la hng dan thong dung va noi tieng trong viec mo ta moi trng mang, no mo ta phng thc hoat ong cua phan cng va phan mem da



tren kien truc phan tang va cung cap khung tham chieu mo ta cac thanh phan mang hoat ong ra sao. MO HNH THAM CHIEU OSI NH NGHA CAC QUI TAC CHUAN SAU : + Cach thc cac thiet b giao tiep va truyen thong c vi nhau. + Cac phng phap e cac theit b tren mang khi nao c truyen va khi nao khong c truyen d lieu. + Cac phng phap e am bao truyen ung d lieu va ung en ch. + Cach thc van tai, truyen, sap xep va ket noi d lieu vi nhau. + Cach thc am bao cac thiet b mang duy tr toc o truyen d lieu thch hp. + Cach thc bieu dien 1 bit tren thiet b truyen dan. CAU TRUC MO HNH OSI : Mo hnh OSI co 7 lp moi lp mo ta 1 phan chc nang oc lap. S tach lp em lai nhng li ch sau. + Chia hoat ong thong tin mang thanh nhng thanh phan nho hn, n gian hn giup chhung ta de dang khao sat va tm hieu. + Chuan hoa cac thanh phan mang e cho phep phat trien mang t nieu nha cung cap san pham. + Ngan chan c tnh trang thay oi 1 lp lam anh hng en cac lp khac nh vay giup cho moi lp phat trien oc lap hn.



NGUYEN TAC HOAT ONG TONG QUAT OSI

Gia s co 2 may tnh ket noi vi nhau. Ban truyen d lieu t may nay sang may kia. Muon truyen d lieu gia 2 may th phai am bao 2 may phai co cung giao thc, Ngha la chung phai hieu nhau trc khi viec thc hien truyen d lieu gia chung. Qua trnh truyen d lieu tong quat thc hien theo nguyen tac sau

+ Tai may truyen d lieu : D lieu se c truyen thong qua 7 lp ( lan lt t lp 7 en lp 1 )trong mo hnh OSI. Tai moi lp trong mo hnh OSI no se them vao nhng thong tin ac trng cua lp o vao au va cuoi cua d lieu.

+ Tai may nhan d lieu : D lieu nhan c cung c truyen thong qua 7 lp ( t lp 1 en lp 7 ) trong mo hnh OSI. Tai moi lp trong mo hnh OSI no se g bo i nhng thong tin ac trng tai tng lp au va cuoi cua d lieu, tai tao lai d lieu ban au.



CHC NANG CUA CAC LP TRONG MO HNH THAM CHIEU OSI + Application Layer ( Lp ng dung ) La giao dien gia cac chng trnh ng dung cua ngi dung va mang. Lp nay khong cung cap cac dch vu cho bat c lp nao trong mo hnh OSI. Lp Application lien quan en viec cung cap cac dch vu ng dung trong he thong mang bao gom : file services , Print services, Application services. + Presentation Layer ( Lp trnh bay ) Lp nay chu trach nhiem thng lng va xac lap dang d lieu c trao oi. No am bao thong tin ma lp ng dung cua 1 he thong gi i th lp ng dung cua he thong khac co the oc c. Lp Presentation thong dch gia nhieu dang d lieu khac nhau thong qua 1 dang chung, ong thi no cung nen va giai nen d lieu, quan ly cac cap o nen d lieu nham giam so bit can truyen. Data formatting (nh dang d lieu): Bit/byte-orther translation : Th t truyen bit/byte c qui c bi qui tac gi va nhan. Character code translation ( bang ma ky t ): moi loai he thong may tnh se s dung 1 loai bang ma hoa ky t khac nhau . VD : e bieu dien ky t cua tieng Anh th Minicomputer va Microcomputer s dung bang ma ASCII(American Standard Code for Information Interchange) trong khi o may tnh Mainframes cua IBM s dung bang ma EBCDIC(Exchange Binary Code Decimal Interchamge Code)

File syntax translation ( tap tin dang cu phap ): La nhng kieu nh dang khac nhau gia cac loai may tnh khac nhau. VD : Tap tin thong ke trong may kieu Macintosh s dung s lien ket gia 2 tap tin data fork va resource fork. Trong khi may PC ch bao gom 1 tap tin.



Encryption ( Ma hoa d lieu ): Viec ma hoa d lieu tuy theo nhu cau can bao mat ve thong tin ma ngi ta co cac cach ma hoa d lieu khac nhau nh sau : Public key ( Bang ma thong dung ): Phng phap ma hoa chung a c nh theo chuan quoc te.



Private key ( Bang ma rieng ) : Phng phap ma hoa rieng khong tuan theo chuan quoc te. No tuan theo qui tac ma ngi ma hoa lam ra.

+ Session Layer ( Lp phien ) Chu trach nhiem quan ly ve phng phap hoi thoai gia 2 may tnh bi cac

chc nang thiet lap, quan ly va nh gii han phien thong tin gia 2 thiet b truyen va nhan, ieu chnh ben nao truyen va truyen trong bao lau va ngc lai.

Cac phng phap truyen thong tin thng c ap dung Simplex dialogs ( n cong ) Hafl-duxplex dialogs ( Ban song cong ) Full-duxplex dialogs ( Song cong )

Session Player hoat ong t nhat thong qua 4 bc Connection establishment ( Thiet lap ket noi) Data Tranfer ( Truyen d lieu ) Connection release ( Ngat ket noi ) Error Correction ( Kiem tra loi )



Giai oan thiet lap ket noi se thiet lap thong so cho phien thong tin. Thc te qua trnh thiet lap ket noi se lam 1 vai nhng nhiem vu sau : + Ch ro nhng dch vu c yeu cau e s dung. + Tham nh quyen ang nhap va nhng thu tuc bao mat khac. + Thoa thuan gia cac bo giao thc va nhng thong so giao thc. + Thong bao ket noi IDs + Thiet lap ieu khien hoi thoai, nh bao nhan tin va thu tuc truyen lai Sau khi thiet lap ket noi, Thiet b lien quan co the khi chay hoi thoai va bat au giai oan truyen d lieu. Lp phien co the cung ket hp chat che vi nhng giao thc e phuc hoi lai nhng thong tin b h hong. Kiem tra viec ket noi co b mat hay khong. Sau khi d lieu c truyen het se ngat ket d lieu va ngat ket noi gia nhng thiet b. + Transport Layer ( Lp van chuyen ) Phan oan d lieu tai he thong may truyen va tai thiet lap d lieu tai he thong may nhan, am bao viec ban giao cac thong iep chnh xac.Lp nay bao gom cac hoat ong sau Repackaging ( Xep th t cac phan oan ) : Khi 1 thong iep ln c tach thanh nhieu phan oan nho e truyen. Khi nhan cac phan oan nho lp van chuyen se sap xep th t cac phan oan trc khi rap noi thanh thong iep ban au. Error Control ( Kiem soat loi ) : khi co phan oan trong qua trnh truyen b that bai, sai hoac trung lap no se yeu cau truyen lai. End to End Flow control ( Kiem soat luong chay d lieu ) : Lp van chuyen s dung tn hieu bao nhan e xac nhan a nhan c cho ben gi. Ben gi se khong truyen tiep cac phan oan d lieu neu nh ben nhan cha gi i tn hieu bao a nhan c phan oan d lieu trc o ay u.

Cac phng thc truyen goi d lieu: Circuit switching :

Thiet lap ng dan va gi ng dan trong suot qua trnh truyen. D lieu i theo 1 ng truyen nhat nh a c nh san. Mat nhieu thi gian thiet lap ket noi gia thiet b truyen va nhan, Nhng lu thong khac tren mang khong the chia se moi trng truyen thong do bang thong con lai hep.



Message switching : Thiet lap ket noi truyen d lieu theo nhieu hng khac nhau e i en ung

ni can en ( Dang nay ch thiet lap ng dan va gi ng dan trong tng oan d lieu truyen qua )

Packet switching : D lieu c chia thanh nhieu goi nho moi goi nho c truyen i theo

nhieu hng khac nhau tren he thong mang. Thiet lap ket noi va gi ket noi trong



thi gian rat ngan. Do truyen dang goi nen qua trnh truyen van co the chia se c moi trng truyen.

Virtual Circuit Packet Switching : Chuyen mach ao hoat ong thiet lap ket noi gia 2 thiet b thong. Khi thiet

b bat au phien lam viec no thiet lap cac thong so cho thong tin, Chang han nh kch thc toi a cho 1 ban tin chuyen i, ca so truyen thong va nhng ng dan mang. Khi hnh thanh virtual circuit xac nh ro ng dan thong qua s tng tac gia nhng thiet b truyen thong. Mach ao nay la gi nguyen tnh trang cho en khi thiet b ket thuc thong tin.

Packet switching co nhng thuan li sau : Packet switching toi u hoa viec s dung bang thong bi v no cho phep nhieu thiet b nh tuyen nhng goi d lieu thong qua nhng kenh mang. Tai bat ky 1 thi iem nao chuyen mach co the nh tuyen nhng goi d lieu en vai thiet b ch khac nhau. ieu chnh tuyen ng i cho cac goi d lieu e at c hieu qua cao nhat. Bi v toan bo ban tin kkong lu tr tai chuyen mach trc khi truyen tiep, S truyen tre t hn nhng so vi message switching.

+ Network Layer ( Lp mang ) Chu trach nhiem thiet lap cac thong iep, dien dch a ch va ten logic thanh a ch vat ly ong thi no cung chu trach nhiem gi cac packet t nguon en ch. Lp nay ng i t may tnh nguon en may tnh ch. No quyet nh d lieu se truyen theo ng nao da vao tnh trang u tien dch vu va cac yeu to khac.



No quan ly lu lng tren mang, chuyen oi goi tin, nh tuyen va kiem soat s tac nghen d lieu. Neu thch ng mang tren bo nh tuyen khong the truyen u nguyen oan d lieu ma may tnh nguon gi i th lp network tren bo nh tuyen se chia d lieu thanh nhng n v nho hn. au nhan lp network rap noi lai d lieu ( packet hay datagram )

+ Data link Layer ( Lp lien ket d lieu ) : Gi cac khung d lieu t tang network en tang physical. au nhan no ong goi d lieu dang tho t tang physical thanh cac khung d lieu. Cung cap kha nang truyen d lieu xuyen qua 1 lien ket vat ly. Tai ay cac bit en t lp physical c lien ket thanh cac frame. Lp nay lien quan en - a ch vat ly - Mo hnh mang - C che truy cap ng truyen - Thong bao loi - Th t phan phoi frame - ieu khien dong. Lp data link c phan lam 2 lp con LLC va MAC MAC ( Media Access Control ) : ieu khien khi nhieu tram cung truy cap chia se 1 kenh truyen thong e truyen thong e truyen thong tin. Lp MAC co the cung cap thong tin ve a ch cho viec thong tin gia cac thiet b mang. LLC ( Logical Link Control ) : lp LLC thiet lap va duy tr lien ket gia nhng thiet b thong tin

+ Physical Layer ( Lp vat ly ) : tang nay truyen cac luong bit d lieu thong qua lien ket vat ly( cap mang). nh ngha cac qui cach ve ien, thu tuc va cac ac ta chc nang dung e kch hoat, duy tr va ngat lien ket vat ly gia cac thiet b au cuoi. 1 so ac iem trong lp vat ly nay bao gom : - Mc ien the - Khoang thi gian thay oi ien the - Toc o d lieu vat ly - Khoang ng truyen toi a - Cac au noi vat ly



IV. CAC BC CHI TIET TRONG VIEC VAN CHUYEN GOI D LIEU : Sinh ven da vao qua trnh phan tch 7 lp tren e xay dng qua trnh chi tiet van chuyen d lieu gia 2 may tinh thong qua moi trng mang. _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ V. MO HNH TCP/IP Mo hnh tham chieu TCP/IP tng t nh mo hnh tham chieu OSI. Tai moi phan lp no co 1 so tnh chat sau :

APPLICATION TRANSPORT INTERNET

NETWORK INTERFACE Lp Application : Bao gom cac ng dung nh FTP, HTTP, SMTP.. Lp Transport : Bao gom 2 ghi thc TCP va UDP

Lp Internet : Nghi thc IP Lp Network layer : Co tnh chat tng t nh 2 lp data link va physical cua mo hnh OSI Cac bc ong goi d lieu trong mo hnh TCP/IP

DATA TCP/ DATA

TCP / DATA / IP LD/ TCP / DATA / IP / LD

Sinh ven da vao 7 lp OSI va TCP/IP e so sanh 2 mo hnh.



________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

VI. HO IEEE 802 IEEE (institute of Eletronic Engineers = vien cac ky s ien t )la mot to chcchuyen nghiep ln nhat the gii vaco anh hng rat quan trong oi v viec xay dng cac chuan. Uy ban 802 cua IEEE d9a phat trien mot loat cac chuan cho LAN, MAN, va WAN. Cac chuan nay c tha nhan va c ISO tai cong bo di dang chuan ISO 802. Mi hai tieu ban a xem xet chuan 802 (mot tieu ban th mi ba a c e ngh e phat trien chuan 100BASEX). Hnh 1.6 mihn hoa v tr cua moi chuan trong mo hnh tham khao OSI. IEEE 802.2 chuan IEEE802.2dnh ngha mot tang con LLC c cac giao thc tang pha di khac s dung. Do cac giao thc tang pha di s dung ch mot tang giao thc LLC n le, nen cac giao thc tang mang co the c thiet ke oc lap vi tang vat ly cua mang va cac thc thi tang con MAC. LLC chap vao cac goi tin mot phan au nh danh cac giao thc tang pha tren, ket hp vi khung. Phan au cung khsi bao cac tien trnh la nguong va ch cua moi goi tin. I2EEE 802.3 Chuan IEEE 802.3 nh ngha la mot mang phai, sinh t mang ethernet, thoat au c phat trien bi cac hang digital, intel,xerox. Chuan nay nh ngha cac ac tnh lien quan en tang con MAC cua tang noi ket d lieu va tang vat ly OSI. Ngoai mot chi tiet khac biet nho kieu khung, cac chc nang IEEE 802.3 Ethernet giong y het DIX Ethernet v.2. tham ch hai chuan co the cung ton tai



tren cung mot he cap, tuy cac thiet b dung chuan nay khong the trryen thong tin trc tiep vi cac thiet b dung chuan kia. Tang con MAC dung dang truy cap tranh chap co ten CSMA/CP. K thuat nay giam bt tnh trang va cham bang cach e moi thiet b lang ch mang e xac nh no a yen hay cha( cam ng tan so tai); mot thiet b ch gang truyen khi mang yen lang. ieu nay giup giam bt song khong loai han cac s co va cham bi cac tn hieu phai mat mot thi gian nhat nh e loan tryen qua mang. Khi cac thiet b truyen chung tiep tuc lang ch, do o chung co the phat hien ra mot va cham neu no xay ra. Khi mot va cham xay ra, tat ca cac thiet b ngng tryen va gi mot tn hieu ang ket e thong bao cho tat ca cac tram ve s co va cham. Sau o moi thiet b i mot thi lng ngau nhien trc khi gang tryen lai. To hp bao ve nay lam giam bt ang ke cac s co va cham tren tat ca ngoai tr cac mang ban ron nhat. Phan nh ngha tang vat ly mo ta phng phap phat tn hieu( ca day tan c s lan dai tan rong ieu san co), cac toc o d lieu, van tai, va cac topo. Vai bien the tang vat ly cung c nh ngha. Moi bien the c at ten theo mot qui c qui nh toc o phat tn hieu(1 hay 10) Mbps, che o giai tan c s( BASE) hoac giai tang( BROAD), va mot ch nh cac ac tnh van tai. Ghi chu: Nganh cong nghiep a khong nhat tr trong viec dung ung an ten Ethernet. Xerox a a ten Ethernet vao lnh vc cong, co ngha la khong ai co the xac nhan tham quyen tren no. Nhng ngoi theo chu ngha thuan tuy thng hay cho rang ethernet ch co ngha la chuan digitalintelxerox ban au. Tuy nhen, ngi ta lai thng dung thuat ng e ch bat k mang nao da tren phng phap ieu khien ttruy cap CSMA/CD. Thong thung ta phai cu the ve chuan ap dung cho mot cau hnh mang nhat nh. Chuan ban au co ten la ethernetversion 2( version1 van thnh thoang c dung) hoac Ethernet 2 chuan IEEE c phan biet bi ten uy ban cua no 802.3 S phan biet ay la quang trong bi ethernet version 2 va ethernet 802.3 s dung cac kieu khung khong tng thch. cac thiet b ch mot kieu khung se khong the truyen thong vi cac thiet b dung kieu khung kia. IEEE802.4 Chuan 802.4 mo ta mot mang co topo buyt vat ly ieu khien viec truy cap van tai theo c che the bai. Chuan a c thiet ke e thoa cac nhu ccau cua cac he thong t ong hoa ve cong nghiep nhng lai t c pho dung. Ca hai cap hnh giai tan c s lan day tan rong( dung cap ong truc 75 ohm) ieu co san. IEEE802.5



Chuan IEEE 802.5 xuat hpat t mang tokenring cua IBM, s dung topo logic vongkhau va c che ieu khien trruy cap van tai goc the bai. Toc o d lieu 1, 4, va 16 Mbps a c nh ngha. Chuan IEEE 802.5 khong mo ta mot he au cap. Hau het cac thc thi ieu da tren he cap IBM, s dung cap xoan cap oc au day theo hnh sao vat ly. IEEE802.6 Chuan IEEE802.6 mo ta mot chuan MAN ten DQDP( distributed queue dual bus= buyt oi co hang i phan phoi). Khong ch la mot cong nghe mang d lieu, DQDP rat thch hp vi cac phien truyen d lieu, tieng, va video. Manh da tren cap quang theo cau hnh topo buyt oi. Lng lu thong tren moi buyt la mot chieu. Khi hoat ong theo tng cap, hai buyt cung cap mot cau hnh dung loi. Bang thong c phan bo bang cac khe thi gian, va cac che o ong bo va b bo ieu c ho tr. IEEE802.9 Chuan IEEE 802.9 ho tr mot kenh d bo 10 Mbps, cung vi 96 kenh 64 KBPS( tong bang thong 6 Mbps) co the chuyen trach cac luon d lieu cu the. Tong bang thong la 16 mbps. Chuan nay co ten la Ethernet ang thi(IsoEnet) va c thiet ke cho cac c s co lg lu thong gian oan va quan trong ve thi gian. IEEE802.11 IEEE802.11 la mot chuan cho cac lan vo tuyen, hien dang phat trien. Mot phng phap CSMA/CD a c cchng nhan, nhng chuan chung cuoc van ang ch giai quyet. IEEE 802.13 Chuan IEEE 802.13 5a tren mot e ngh 100 Mbps cua cac hang AT&T, IBM va hewlettpackard. c goi la 100 VGAnyLAN, mang nay da tren mot topo au day hnh sao va mot phng phap truy cap goc tranh chap qua o cac thiet b cho o cai au day ve mot nhu cau truyen d lieu. Cac thiet b ch co the truyen khi uc o cai giao giay phep. Chu trng cua chuan nay la cung cap mot mang cao cap co the hoat ong trong cac moi trng hon hp ethernet va tokenRing bang cach ho tr ca hai kieu khung



MOI TRNG TRUYEN THONG Tren mot mang bat ky, cac iem noi tren mang phai truyen thong vi nhau c thong qua mot dang truyen tai nao o. Con ngi co the truyen thong tin vi nhau qua ng day ien thoai hoac song am thanh trong khong kh. May tnh co the truyen thong thong qua day cap, anh sang va song radio. Ky thuat truyen tai cho phep may tnh gi va nhan cac thong iep. Chng nay mo ta loai vat tai truyen pho dung nhat tren mang. Ta se tm hieu cac noi dung sau : I. CAC TAN SO TRUYEN



Vat truyen tai giup truyen cac tn hieu ien t t may tnh nay sang may tnh khac. Cac tn hieu ien t nay bieu at cac gia tr d lieu theo dang so nh phan (bat/tat). Cac tn hieu nay c truyen thong qua mang bang mot to hp cac thiet b ien t (cac board mach, hub, ) va vat truyen tai (day cap, song vo tuyen, ) cho en khi chung en c may tnh ch. o, chung lai c chuyen oi thanh cac tn hieu thanh cac d lieu ben trong may tnh nhan.

Tat ca cac tn hieu truyen gia cac may tnh eu bao gom mot dang song ien t (electromagnetic - EM) nao o, t cac tan so radio en viba va tia hong ngoai. Cac vat tai khac nhau c dung e truyen cac tn hieu tuy theo tan so cua dang song EM.

Cac song tan so radio thng c dung e phat tn hieu LAN. Cac tan so radio co the c dung vi cap ien (xoan cap hay ong truc) hoac thong qua viec truyen phu song radio.

Cac ky thuat truyen viba c dung e truyen thong gia cac tram at va cac ve tinh hay dung e truyen iem-iem tren mat at. Cac song viba cung co the c dung theo cac dang cong suat thap e phu rong cac tn hieu t mot tram phat en nhieu tram thu. Cac mang ien thoai te bao la nhng v du ve cac he thong dung cac tn hieu viba cong suat thap e phu rong cac tn hieu.

Tia hong ngoai co the c truyen tren cac khoang cach tng oi ngan va co the c phat song gia hai iem hoac t mot iem phu song cho nhieu tram thu. Co the truyen tia hong ngoai va cac tan so anh sang cao hn thong qua cap quang. ac tnh cua vat tai truyen : Moi loai vat truyen tai eu co cac tnh nang ac biet thch hp vi mot kieu dch vu cu the vi cac ac tnh sau ay :Gia thanh, Cac yeu cau cai at, Bang thong, Suy hao, Mien nhieu ien t. Ba ac tnh sau se c giai thch ky hn. BANG THONG :

Trong lnh vc mang may tnh, thuat ng bang thong (bandwidth) co ngha la so o cong suat cua mot vat tai e truyen d lieu. Mot vat tai co cong suat han che se co bang thong thap. Co the v bang thong nh cac voi nc. Neu mot voi nc ng knh na inch co the tai luong nc t nho giot len en bang thong 2 gallon/phut th co the xem voi o co mot bang thong 2 gallon/phut.



Cac toc o truyen d lieu thng c phat bieu di dang cac bit co the truyen moi giay. Tren ly thuyet, mot LAN Ethernet co the truyen 10 trieu bit/giay va co mot bang thong 10 megabit/giay (Mbps). Bang thong cua mot cap phan nao c xac nh bi chieu dai cap. Mot oan cap ngan thng co bang thong ln hn mot oan cap dai va la mot ly do ma moi thiet ke cap ch nh cac chieu dai toi a e chay cap. Neu vt qua cac gii han nay, cac tn hieu tan so cao nhat co the b hong va co the bat au xay ra loi trong cac tn hieu d lieu. Ghi chu : Thuat ng bang thong cung co mot ngha khac. Trong lnh vc ien t bang thong co ngha la mien cac tan so san co gia tan so gii han thap va tan so gii han cao. Cac tan so c o bang Hertz (Hz) hoac so chu ky/giay. Bang thong mot tuyen thoai la 400-4,000Hz, ngha la tuyen nay co the truyen cac tn hieu theo cac tan so t 400 en 4,000 chu ky/ giay. SUY HAO :

Suy hao la so o mc suy yeu cua mot tn hieu khi no di chuyen qua mot vat tai. ay ta khong e cap hien tng suy hao theo ngha chnh quy ma ch xet en tac ong cua no oi vi kha nang van hanh.

Suy hao la ly do th hai ma cac thiet ke cap phai ch nh cac gii han ve chieu dai chay cap. Khi cng o tn hieu tut xuong di mot so gii han nhat nh, cac thiet b ien t ang nhan tn hieu se kho long co lap tn hieu ban au vi am nhieu hien dien trong moi phien truyen ien t. Hieu ng nay giong het nh ang gang bat song cac tn hieu radio t xa. Cho du co the thu c tn hieu tren ai radio, song noi chung am thanh van cha nhieu am nhieu. NHIEU IEN T :

Nhieu ien t (electromagnetic interference EMI) bao gom cac am nhieu ien t ben ngoai lam bien dang tn hieu trong mot vat tai. Khi nghe mot ai phat thanh AM, ta thng nghe am nhieu do cac ong c hay tia chp gay ra.

II. MOI TRNG TRUYEN HU TUYEN

1. Cap dung cho mang ien thoai : La loai day thng dung trong lam day ien thoai dan tn hieu t tram tong ai ien thoai en tram ien tong ai ien thoai hay t tram ien tong ai ien thoai en ni s dung. Chung ta thng s dung ket noi vi internet thong qua ng day nay.

+ T tong ai ni s dung : thng la 1 oi day va chung c phan lam 2 loai goi la cap inside va cap outside.



+ T tong ai tong ai : Thong thng loai day nay thng c cau thanh tng oi va bo lai vi nhau thanh tng bo. Tuy theo cau truc ma no c bo thanh tng bo : 5 oi, 10 oi, 25 oi, 50 oi.. va no co qui nh mau sac e nhan dang thong thng nh sau (TC USA)

5 mau chnh 5 mau phu Trang Dng o Cam en Luc Vang Nau Tm Xam

Truyen tn hieu tng t co tan so len en 250 KHz vi c ly len en 5Km 6Km. Truyen tn hieu so toc o toi a 100Kb/s vi tram lap 2 Km - 3 Km. Neu muon truyen xa hn phai co mach K tang tn hieu va phai chu y en kha nang b meo xuyen am neu vo boc chong nhieu khong tot.

2. Cap ong truc (coaxial cable) : La loai cap au tien s dung cho he thong mang LAN. Goi la cap ong

truc v co hai day dan dung chung mot truc, ng cap thng c xem la ong truc.

+ Cau tao cap ong truc : - Mot day dan trung tam, thng la day ong ac - Mot day dan pha ngoai tao thanh mot ng ong bao quanh day dan trung tam. Day dan nay co the dung cac si day kim loai dang li, la kim loai, hoac ca hai. Do day dan nay cung bao ve day dan pha trong khoi b EMI, nen con c goi la mang chan.



- Mot tang cach ien e gi day dan pha ngoai cach eu vi day dan pha trong. - Mot vo bao bang nha e bao ve cap khong b dap. + Phan loai cap ong truc :

Thin net ng knh : 0.25 inch Kha nang truyen MAX = 185 m Tong tr : 50 ohm Gia thanh : Re Dung lng : 2.5 Mbps ( ARCnet) 10 Mbps ( Ethernet) EMI : De b bc xa tn hieu

Thick net ng knh : 0.50 inch Kha nang truyen MAX = 500 m Tong tr : 50 ohm Gia thanh : at Dung lng : 2.5 Mbps ( ARCnet) 10 Mbps ( Ethernet) EMI : De b bc xa tn hieu

+ Cach au noi :

Cap ong truc thng c cai at theo 2 cau hnh : mac noi tiep t thiet b nay sang thiet b khac (Ethernet) va hnh sao (ARCnet).



3. Cap xoan oi : Cap xoan oi gom 2 day ong xoan lai vi nhau. Ky thuat xoan lam giam bc xa gay nhieu en nhng ng cap lan can.

+ Cap STP ( Shield Twisted Pair ) : Gom 4 oi day, 4 oi day lai

c boc trong loi li kim loai. Co kha nang chong nhieu ien gia cac oi day ben trong cap va nhieu ben ngoai cap tham nhap vao. Tr khang thng 150 Ohm, Toc o va thong lung t 10 Mbps en 100 Mbps. Chieu dai cap Max khi s dung trong mang may tnh = 100 met. Loai nay at tien va kho khan khi lap at nen t c s dung nhieu.



+ Cap UTP ( Unshield Twisted Pair ) : Gom 4 oi day c boc 1 lp cach ien va moi oi day c xoan lai vi nhau, 4 oi day c boc trong 1 ong nha. Tr khang thng 100 Ohm, Toc o va thong lung t 16 Mbps en 500 Mbps. Chieu dai Max cap khi s dung trong mang may tnh = 100 met. Loai nay gia thanh re, nho gon, de dang lap at. Qui nh ve mau day cap UTP

White Green Green White Orange Orange White Blue Blue White Brown Brown

So th t day Chun A Chun B 1 White Green White Orange

2 Green Orange 3 White Orange White Green 4 Blue Blue 5 White Blue White Blue 6 Orange Green 7 White Brown White Brown 8 Brown Brown



Nguyen tac au noi cap UTP, STP Node to Node, hub to hub

Node to Hub, hob to node



4. Cap quang : Si quang cau tao gom lp ruot ben trong lam bang thuy tinh silic cc thuan va co chiet suat cao hn lp vo bao boc ben ngoai lam bang nha deo chong am t, mai mon, va cham va cac nguy c h hong khac. Tuy nhien loai nay gia thanh rat cao va kho che tao. Sau nay ngi ta che tao loai si quang gom thuy tinh nhieu thanh phan. Loai nay gia thanh thap hn nhng van ap ng c nhu cau s dung.

Si quang thong thng co ng knh t 2 um - 125 um. Truyen tia

sang co tan so 10KHz en 10 GHz. Toc o truyen 100Mbps co the at ti 2Gbps. Chieu dai Max cap khi s dung trong mang may tnh co the len en vai Km.

e truyen tn hieu trong si quang : Tn hieu dang tng t phai chuyen oi sang dang tn hieu so roi s dung diode phat quang chuyen oi sang dang anh sang ri rac truyen i trong si quang va tai au thu ta s dung diode thu quang e thu lai anh sang ri rac sau o chuyen oi ve trang thai ban au.



Tuy theo kch thc si quang ma ta co cac cach truyen tn hieu anh

sang trong si quang sau. Neu ng knh si ln, chiet xuat ruot ong eu cao hn lp vo boc,

goc ti cua tia sang nho khi en au si cap tia sang se c phan chieu toan phan nhieu lan trong qua anh sang trnh truyen doc theo si cap. Ta co the truyen 1 luc nhieu tn hieu tren cung 1 si cap nhng do anh hng cua phan xa toan phan nhieu lan trong qua trnh anh sang lu thong trong si cap dan en tn hieu tai au thu co the khong ong pha nhau va dan en toc o truyen bi han che.

Neu ng knh si that nho chiet suat si ong eu th ch 1 tia tn

hieu c truyen qua si quang.

Tn hieu tng t

Tn hieu dang so

Phat anh sang ri rac

Si quang

Thu anh sang ri rac

Tn hieu dang so

Tn hieu tng t



Neu chiet xuat si khong ong eu, chiet xuat cao nhat tai tam si quang va giam dan khi ra ngoai vo th tia sang khong c phan xa toan phan tai mat tiep giap gia ruot va vo luc o no se phan xa toan phan ngay trong si quang.

5. Bang thong ke thong so cac loai cap :

Kieu cap Lap at Thong lng Pham vi Coaxial thinnet De dang lap at 10Mbps 185 met Coaxial thcknet De dang lap at 10Mbps 500 met STP ( Shielded twisted pair )

De dang lap at 16Mbps en 500Mbps

100 met

UTP ( Unshieded twist pair )

Mac tien, De dang lap at

10Mbps en 100Mbps

100 met

Fiber-optic Mac tien, kho lap at 100Mbps Vai kilomet

MOI TRNG TRUYEN VO TUYEN

Infrared ( hong ngoai) Laser Narrow-band radio ( Song radio bang thong hep ) Spread-spectrum radio ( Song radio bang thong rong ) Microwave ( song cc ngan ) Kh quyen qua at va khong gian la moi trng truyen vo tuyen. Tn hieu

truyen c trong moi trng vo tuyen phai lan truyen di dang song ien t.

NI PHAT TN HIEU

NI THU TN HIEU

KHONG GIAN

MOI TRNG VO TUYEN

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Nh chung ta biet tn hieu am tan co tan so : 20 Hz 20 KHz ay chnh la tan so ma tai ngi cam nhan c va tan so nay qua thap khong co kha nang lan truyen i xa trong khong gian. e tn hieu am tan co kha nang truyen xa trong khong gian ta s dung ky thuat ieu che e gi song am tan tren 1 song cao tan roi sau o cho no bc xa ra ngoai khong gian di dang song ien t.

Ky thuat gi song am tan tren 1 song cao tan goi la ky thuat ieu che va c thc hien theo nguyen tac sau :

Truyen song trc tiep : truyen thang t tram phat an tram thu theo ng nhn thay

Truyen thong qua tram tiep song hay tram lap : Tram lap co the at tren cao, hay

dung ve tinh a tnh.

Trai at

Tram phat Tram thu

Tn hieu am tan (AF)

ieu che ( MIX)

Dao ong cao tan ( OSC RF ). Song mang

tin

ng nhn thay



CAC KIEN TRUC VA CONG NGHE MANG LAN

I. GII THIEU : Mang c tao nen bi cau truc phan cng, giao thc, thiet b truyen, cau hnh mang. Mot cau hnh mang(topo) la 1 s o cac mat noi se c ket noi nh the nao, cac thiet b tai mat noi co chc nang nh the nao trong viec ket noi vi cac vi cac thiet b khac. Yeu to hnh thanh len topo mang chnh la s chon la phng phap truy xuat moi trng. Phng phap truy xuat la tap hp nhng nguyen tac ve viec phan chia mc o phien truyen.

Chng nay se gii thieu ve : - Phng phap truy xuat moi : CSMA/CD, CSMA/CA, token passing - Cac cau hnh mang s dung cac phng phap truy xuat moi trng

tren.

II. CAC PHNG PHAP TRUY CAP NG TRUYEN La tap hp cac qui luat quan tr cac nut mang cung chia se moi trng

truyen dan. 1. Tranh chap ( Contention ) : Tranh chap phng tien truyen dan en trc phuc vu trc.

* CSMA / CD + CS (Carier Sensor) : Cam bien song mang. Cac tram lam thc hien

viec quan sat cng o lu thong tren mang e nhan biet ng truyen co trong hay khong.

+ MA (Multiple Accesse) : a truy cap. Cho phep nhieu tram cung truy cap 1 ng truyen trong tai cung 1 thi iem.

+ CD (Cosllision Detect) : Phat hien xung ot Vi CSMA/CD moi iem tram lam viec tren mang eu co quyen bnh ang

trong viec tham nhap vao kenh truyen. Neu ca 2 tram lam viec cung luc lang nghe ng truyen nhan thay ng truyen ang ranh va ca 2 cung truyen d lieu - Xay ra xung ot lam viec truyen cua 2 tram b gian oan. Ca 2 tiep tuc quan sat mang va ch thi gian ngau nhien cho lan truyen ke tiep.



* CSMA / CA + CA ( Coillision Avoidance ) Tranh xung ot Da vao cac canh bao truyen thong lam giam s xung ot e tang cng

o lu thong tren mang.

2. Hoi vong (Polling)

Mot thiet b c xac nh e lam cong viec hoi vong se lan lc hoi cac thiet b khac se xem chung co thong tin e truyen truyen hay e nhan d lieu hay hay khong.

S hoi vong ato ra cong bang trong lu thong tren he thong mang.

3. Truyen the bai (Token Passing) S dung 1 khung goi la the bai e thiet lap th t truyen d lieu. Cac may tnh tren he thong mang nhan th t e chiem phng tien truyen dan. May nao can truyen d lieu phai i en khi nhan c the bai mi co quyen truyen d lieu. Cac mang s dung phng phap nay :



+ Token Ring + IEEE Standards 802.4 + FDDI ( Fiber distribued data interface )

4. Yeu cau u tien (Demand Priority) : la phng phap s dung cho nhng loai mang co toc o mi 100 MBps hay 100VG-AnyLAN standard. Trong phng phap nay nhng mat noi mang c noi ti HUB vao1 co the c noi ti nhng HUB khac v vay s tranh chap xay ra HUB. Demand Priority cung cap s van hanh cho nhng loai d lieu vi quyen u tien. en trc phuc vu trc. Neu tranh chap xay ra th d lieu nao co quyen u tien cao hn se c truyen trc. III. CAC KIEN TRUC MANG (TOPOLOGY) : 1. Khai niem : - Network topology la s o dung bieu dien cac kieu sap xep, bo tr vat ly

cua may tnh, day cap va nhng thanh phan khac tren mang theo phng dien vat ly.

- Co hai kieu kien truc mang chnh la : - Kien truc vat ly (physical topology) : mo ta cach bo tr ng truyen thc s cua mang, - Kien truc logic (logical topology) : mo ta con ng ma d lieu that s di chuyen qua cac nut mang.

2. Cac kieu kien truc mang chnh : * Mang Bus :



- Kien truc Bus la mot kien truc cho phep noi mang cac may tnh n gian

va pho bien nhat. No dung mot oan cap noi tat ca may tnh va cac thiet b trong mang thanh mot hang. Khi mot may tnh tren mang gi d lieu di dang tn hieu ien th tn hieu nay se c lan truyen tren oan cap ti cac may tnh con lai, tuy nhien d lieu nay ch c may tnh co a ch so khp vi a ch ma hoa trong d lieu chap nhan. Moi lan ch co mot may co the gi d lieu len mang, v vay, so lng may tnh tren bus cang tang th hieu suat thi hanh mang cang cham.

- Hien tng doi tn hieu : la hien tng khi d lieu c gi len mang, d lieu se i t au cap nay en au cap kia. Neu tn hieu tiep tuc khong ngng, no se doi ti lui trong day cap va ngan khong cho may tnh khac gi d lieu. e giai quyet tnh trang nay ngi ta dung mot thiet b terminator (ien tr cuoi) at moi au cap e hap thu cac tn hieu ien t do.

- u iem : kien truc nay dung t cap, de lap at, gia thanh re. Khi m rong mang tng oi n gian, neu khoang cach xa th co the dung repeater e khuech ai tn hieu.

- Khuyet iem : khi oan cap t oi hoac cac au noi b h ra th se co hai au cap khong noi vi terminator nen tn hieu se doi ngc va lam cho toan bo he thong mang ngng hoat ong. Nhng loi nh the rat kho phat hien ra hong cho nao nen cogn tac quan tr rat kho khi mang ln (nhieu may va kch thc ln).



* Mang Star :

- Trong kien truc nay, cac may tnh c noi vao mot thiet b au noi trung tam (Hub hoac Switch). Tn hieu nay c truyen t may tnh gi d lieu qua hub, tn hieu c khuech ai va truyen en tat ca cac may tnh khac tren mang.

- u iem : kien truc star cung cap tai nguyen va che o quan ly tap trung. Khi mot oan cap b hong th ch anh hng en may dung oan cap o, mang van hoat ong bnh thng. Kien truc nay cho phep chung ta co he m rong hoac thu hep mang mot cach de dang.

- Khuyet iem : do moi may tnh eu phai noi vao mot trung tam iem nen kien truc nay oi hoi nhieu cap va phai tnh toan v tr at thiet b trung tam. Khi thiet b trung tam iem hong th toan bo he thong mang cung ngng hoat ong.



* Mang Ring :

- Trong mang ring, cac may tnh va cac thiet b noi vi nhau thanh mot

vong khep kn, khong co au nao b h. Tn hieu c truyen i theo mot chieu va qua nhieu may tnh. Kien truc nay dung phng phap chuyen the bai (token passing) e chuyen d lieu quanh mang.

- Phng phap chuyen the bai la phng phap dung the bai chuyen t may tnh nay sang may tnh khac cho en khi ti may tnh muon gi d lieu. May nay se gi the bai va bat au gi d lieu i quanh mang. D lieu chuyen qua tng may tnh cho en khi tm c may tnh co a ch khp vi a ch tren d lieu. May tnh au nhan se gi mot mot thong iep en may tnh au gi cho biet d lieu a c nhan. Sau khi xac nhan, may tnh au gi se tao the bai mi va tha len mang. Van toc cua the bai xap x vi van toc anh sang. * Mang Mesh :

- Tng cap may tnh thiet lap cac tuyen ket noi lien iem, do o, so lng tuyen ket noi nhanh chong gia tang khi so lng may tnh trong mang tang len nen ngi ta t dung cho cac mang li ln.



* Mang Cellular : - Cac mang te bao chia vung a ly ang c phuc vu thanh cac te bao,

moi te bao c mot tram trung tam phuc vu. Cac thiet b s dung ca tn hieu radio e truyen thong vi tram trung tam va tram trung tam se nh tuyen cac thong iep en cac thiet b. V du ien hnh cua mang te bao la mang ien thoai di ong.

1. Cac kien truc mang ket hp :

* Mang Star bus : - Star bus la mang ket hp gia mang star va mang bus. Trong kien truc

nay, mot vai mang co kien truc hnh star c noi vi truc cap chnh (bus). Neu mot may tnh nao o b hong th no khong anh hng en phan con lai cua mang. Neu mot hub b hong th toan bo cac may tnh tren hub o se khong the giao tiep c.

* Mang Star ring :

- Mang Star ring tng t nh mang Star bus. Cac hub trong kien truc Star bus eu c noi vi nhau bang truc cap thang (bus) trong khi hub trong cau hnh Star ring c noi theo dang hnh star vi mot hub chnh.



IV. CAC CONG NGHE MANG LAN : 1. Ethernet : - Ethernet chuan thng co cau hnh bus, truyen vi toc o 10 Mbps va da

vao CSMA/CD (Carrier Sense Multiple Access / Collision Detection) e ieu chnh lu thong tren ng cap chnh. Tom lai, nhng ac iem c ban cua Ethernet nh sau : + Cau hnh : bus hoac star. + Phng phap truy cap : CSMA/CD. + Quy cach ky thuat IEEE802.3. + Van toc truyen : 10 100 Mbps, 1Gbps. + Cap : cap ong truc manh, cap ong truc ln, cap UTP, cap xoan.

- Card mang Ethernet : hau het cac NIC cu eu c cau hnh bang cac jump (cac chau cam chuyen) e an nh a ch va ngat. Cac NIC hien hanh c cau hnh t ong hoac bang mot chng trnh chay tren may cha card mang, no cho phep thay oi cac ngat va a ch bo nh lu tr trong mot chip bo nh ac biet tren NIC.

- Qui luat 5-4-3 trong au noi mang : nguyen tac nay cho phep ket hp en nam oan cap c noi bi 4 bo chuyen tiep, nhng ch co 3 oan la noi tram. Theo hnh tren ta thay oan 3, 4 ch ton tai nham muc ch lam tang tong chieu dai mang va cho phep may tnh tren oan 1,2,5 nam cung tren mot mang.

10/100 : 10 hay 100 Mbps Base : Base band 2 : thin net cable 5 : thick net cabe T : UTP cable FL : Fiber optical cable VG : Voice grade X : Multiple media type - Cac loai Ethernet vi bang tan c s :

+ 10Base2 +10Base5 + 10BaseT + 10BaseFL



+ 100BaseT + 100BaseX + 100VG-AnyLAN

a. Chuan 10Base2 : - Cau hnh nay c xac nh theo tieu chuan IEEE 802.3 va bao am tuan

thu cac quy tac sau : + Khoang cach toi thieu gia hai may tram phai cach nhau 0.5m. + Dung cap thinnet (RG-58). + Toc o 10 Mbps. + Dung au noi ch T (T-connector). + Khong the vt qua phan oan mang toi a la 185m. Toan bo he thong cap mang khong the vt qua 925m. + So nut toi a tren moi phan oan mang la 30. + Terminator (thiet b au cuoi) phai co tr khang 50 Ohm va c noi at. + Moi mang khong the co tren nam phan oan. Cac phan oan co the noi toi a bon bo khuech ai va ch co ba torng so nam phan oan co the co nut mang (tuan thu quy tac 5-4-3).

- u iem cua chuan 10Base2 : gia thanh re, n gian.

b. Chuan 10Base5 : - Chuan nay tuan theo cac quy tac sau :

+ Khoang cach toi thieu gia hai nut la 2.5m. + Dung cap thicknet (cap ong day). + Bang tan c s 10 Mbps.



+ Chieu dai phan oan mang toi a la 500m. + Toan bo chieu dai mang khong the vt qua 2500m. + Thiet b au cuoi (terminator) phai c noi at. + Cap thu phat (tranceiver cable) noi t may tnh en bo thu phat, co chieu dai toi a 50m. + So nut toi a cho moi phan oan mang la 100 (bao gom may tnh va tat ca cac repeater). + Tuan theo quy tac 5-4-3.

- u iem : khac phuc c khuyet iem cua mang 10Base2, ho tr kch thc mang ln hn.

- Chu y : trong cac mang ln, ngi ta thng ket hp cap day va cap manh. Cap day dung lam cap chnh rat tot, con cap manh dung oan nhanh.

c. Chuan 10BaseT : - Chuan mang nay tuan theo cac quy tac sau :

+ Dung cap UTP loai 3,4,5 hoac STP, co mc tr khang la 85-115 Ohm. 10 Mhz. + Dung quy cach ky thuat 802.3. + Dung thiet b au noi trung tam hub. + Toc o toi a 10 Mbps. + Dung au noi RJ-45. + So nut toi a la 512 va chung co the noi vao 3 phan oan bat ky vi nam phan tuyen toi a co san. + Chieu dai toi a mot phan oan cap la 100m. + Dung mo hnh vat ly star.



+ Co the noi cac phan oan mang 10BaseT bang cap ong truc hay cap quang. + So lng may tnh toi a la 1024. + Khoang cach toi thieu gia hai may tnh la 2.5m. + Khoang cach cap toi thieu t mot hub en mot may tnh hoac mot hub khac la 0.5m.

- u iem : do trong mang 10BaseT dung thiet b au noi trung tam nen d lieu truyen tin cay hn, de quan ly. ieu nay cung tao thuan li cho viec nh v va sa cha cac phan oan cap b hong. Chuan nay cho phep ban thiet ke va xay dng tren tng phan oan mot tren LAN va co the tang dan khi mang can phat trien. 10BaseT cung tng oi re tien so vi cac phng an au cap khac.

d. Chuan 10BaseFL : - Cac ac iem cua 10BaseFL : toc o toi a : 10Mbps, truyen qua cap

quang. - u iem :

+ Do dung cap quang noi cac repeater nen khoang cach toi a cho mot oan cap la 2000m. + Khong s b nhieu ien t. + So nut toi a tren mot oan cap ln hn nhieu so vi 10Base2, 10Base5, 10BaseT.

e. Chuan 100VG AnyLAN :



- 100VG (Voice Grade) AnyLan la cong nghe mang ket hp cac thanh phan cua Ethernet va Token Ring, dung quy cach ky thuat 802.12.

- Cac ac iem ky thuat : + Toc o truyen d lieu toi thieu la 100 Mbps. + S dung cap xoan oi gom 4 cap xoan (UTP loai 3,4,5 hoac STP) va cap quang. + Kha nang ho tr sang loc tng khung co a ch tai hub nham tang cng tnh nang bao mat. + Chap nhan ca khung Ethernet lan goi Token Ring. + nh ngha trong IEEE 802.12. + Mo hnh vat ly : cascaded star, moi may tnh c noi vi mot hub. Co the m rong mang bang cach them hub con vao hub trung tam, hub con ong vai tro nh may tnh oi vi hub me. + Chieu dai toi a cua oan chay cap noi hai hub la 250m.

f. Chuan 100BaseX : - Tieu chuan 100BaseX Ethernet con goi la Fast Ethernet, la s m rong cua

tieu chuan Ethernet co san. Tieu chuan nay dung cap UTP Cat5 va phng phap truy cap CSMA/CD trong cau hnh star bus vi moi oan cap noi vao mot hub tng t 10BaseT. Toc o 100Mbps.

- Chuan 100BaseX co cac ac ta ng vi cac loai ng truyen khac nhau : + 100BaseT4 : dung cap UTP loai 3,4,5 co 4 cap xoan oi. + 100 BaseTX : dung cap UTP loai 5 co hai cap xoan oi hoac STP. + 100BaseFX : dung cap quang co hai day loi.

2. FDDI ( Fiber Distributed Data Interconnection) :



- Mot trong nhng bat li chnh cua cac mang vong tn bai la s nhay cam

cua chung vi bat trac. V moi may gan tren vong phai chuyen khung cho may ke nen mot hong hoc tren may se lam cho toan mang ngng hoat ong. Phan cng vong tn bai thng c thiet ke e tranh nhng h hong nh the. Tuy nhien, hau het cac mang vong tn bai khong the vt qua khi s ket noi b cat nh khi ng cap noi hai may bong nhien b t.

- Mot so cong nghe mang vong a c thiet ke e khac phuc c hong hoc nghiem trong. V du FDDI la cong nghe mang vong tn bai co the truyen d lieu toc o 100 trieu bit/giay, nhanh gap 8 lan mang vong tn bai IBM va nhanh hn 10 lan mang Ethernet. e cung ng toc o d lieu nhanh nh vay, FDDI dung si quang e noi cac may thay cho cap ong.

- FDDI dung tnh nang d phong e khac phuc s co. Mot mang FDDI gom 2 vong, mot dung e gi d lieu khi moi viec eu on va ch s dung vong th hai khi vong mot hong. Ve mat vat ly, hai ng noi vi mot cap may tnh la khong hoan toan cach biet. Moi si quang c boc trong mot vo nha deo va co mot vo boc cap si bao ben ngoai tng t nh cac ng day ien trong nha. V vay co the lap at hai vong cung mot luc.

ieu thu v la cac vong trong mang FDDI c goi la xoay ngc (counter rotating) v d lieu chay trong vong th hai ngi lai vi hng d lieu vong th nhat. e hieu tai sao lai dung cac vong xoay ngc, hay xet trng hp co s co nghiem trong xay ra. Th nhat v cap si noi hai tram thng i tren cung ng nen khi t mot si th thng la t luon si kia. Th hai, neu d lieu luon luon i theo mot hng tren ca hai si, viec ngat mot tram ra khoi vong (v du khi di chuyen may) se ngat truyen thong cac may khac. Tuy nhien, neu d lieu chuyen theo hng ngc lai ng d tr, cac tram con lai co the cau hnh mang e s dung ng d phong.



BAI TAP : THIET LAP 1 MOI TRNG MANG LAN

XAY DNG VA THIET LAP HE THONG MANG C BAN

CAC BC CHUAN B THIET LAP MANG : - Trc khi thiet ke he thong mang ta can khao sat thong tin, muc ch va yeu cau cua he thong o trc.

VD cac he thong mang thng gap : he thong mang dung e day hoc, he thong mang dung e chi game, he thong mang dung e chia se file, may in, internet.. Tuy theo moi trng hp ma ta co chon cac loai cap mang s dung, bang thong cho he thong, he ieu hanh s dung, giao thc va cac phan mem s dung cho phu hp.

Cac bc tien hanh : - Khao sat s o cau truc vat ly cua ni d tru lap at he thong mang. - Thiet lap s o cau truc mang( da theo chuan 802.3, IEEE). - Lc chon thiet b mang ( NIC, SWITCH, CABLE ) - La chon s dung nhng loai server nao cho cac ng dung. - La chon he ieu hanh cho cac may server mang. - La chon he ieu hanh cho cac may client trong mang. - Cai at cac chng trnh phan mem ng dung can thiet ( phu hp nhu cau

s dung ) - Cai at trnh ieu khien cho NIC - La chon giao thc s dung trong he thong mang ( TCP/IP, IPX/SPX.) - Thiet lap cac ng dung Mail server, - Chia se tai nguyen tren he thong mang ( folder, printer, internet..)



CAC BO GIAO THC Trong chng trc ban a hoc cau truc mang theo tng phan nho cua van e. Mot bo giao thc thng la toan bo mo hnh OSI. Mo hnh OSI la tieu chuan, mo ta cac hoat ong tng lp cua bo giao thc. Mo hnh OSI la 1 cong cu nh ngha trong 1 lp giao thc . Chng nay mo ta chi tiet t lp mang ti lp ng dung. Chung ta nhn mot so giao thc truyen va cac bo giao thc khac nh TCP/IP va IPX/SPX. Mat du 1 so giao thc e tng thch ung vi mo hnh tham khao OSI , s hoan toan tng thch thng khong la chuan. Rat nhieu trong cac bo giao thc nay ra i trc OSI v vay chung ch co the phu hp tng oi vi mo hnh OIS 7 lp muc ch chnh cua mo hnh OSI la lam khung giup chung ta hieu s giao tiep tren mang va so sanh cac bo giao thc vi nhau. PACKETS AND PROTOCOLS (cac goi tin va cac giao thc) Trc khi xem cac giao thc va bo giao thc, chung ta danh chut thi gian on lai 1 so van e lien quan a trnh bay trong cac chngb trc. Muc ch cua mang la trao oi thong tin gia cac may tnh, va cac giao thc la nhng qui tac e may giao tiep vi nhau. May tinh cung nh con ngi e co the trao oi thong tin c vi nhau viec gi va nhan eu tng thch nhau . Neu khong may tnh se ri vao tnh huong boi roi nh khi ban oc 1 cuon sach tieng Nga khi ban ch biet noi tieng Viet. Ban co the phan loai cac nhiem vu ma c ban giao thc phai thc thi theo cac bc i (moi bc ph gom 1 nhom cac nhiem vu phai xay ra trc khi d lieu en kenh tryen. Cac bc nay la cac lp trong 1 bo giao thc nh trong chng 2. Thuat ng lp (layer ro la 1 v du. moi lp trong bo giao thc (nh lp ng dung, trnh bay .. v..v ) cho them thong tin cua chnh lp o vao goi tin. Tai may nhan lp tng ng se nhan va x ly goi tin va nhan. Cac giao thc mo ta d lieu ong goi d lieu t au, roi truyen qua mang va sap xep lai ch thanh tap tin. Viec chia nho d lieu thanh goi nho lam cho lng thong tin tren mang lu thong de dang hn v no khong chiem het phng tien truyen dan nh nhng kieu truyen d lieu co dung lng ln hn. Hn na la cac goi tin nho do tm va sa cha loi de dang hn, tng goi tin c kiem tra va tm loi va ch ro goi tin co loi hay khong (khong phai toan tap tin) e truyen lai.



Thanh phan cua1 goi tin phu thuoc vao giao thc ma ban dung. Thong thng cac goi tin cha nhng phan sau: + Header (phan au): bao hieu bat au 1 goi tin va nhieu thong so quan trong, nh a ch nguon,ch va thong tin thi gian/ ong bo. + Data (d lieu) : cha d lieu can truyen . + Trailer (dau vet): anh dau iem ket thuc cua goi tin va thng cha thong tin sa loi (kiem tra o d vong - CRC Cyclic Redundancy check) Khi d lieu truyen qua lp giao thc moi lp thc hien chc nang mac nh cua chung, nh giao tiep vi 1 ng dung ng dang d lieu kiem tra loi (nh chng 2 a xem cac chc nang cua lp giao thc trong mo hnh OSI. Khi ban hoc chng nay khong phai cac giao thc luon tng thch vi mo hnh OSI ( vi giao thc trc mo hnh OSI th khai niem va thuat ng cua mo hnh OSI lai can thiet e ta chc nang cua cac giao thc) Khi goi tin c truyen, card mang cua may khac tren oan mang se xem goi tin kiem tra a ch ch cua no. Neu a ch ch thch hp vi a ch may th bo ieu hp mang se x ly va cac lp giao thc cua may PC nhan cung se x ly goi tin

Rat nhieu cac nhiem vu c thc hien tai ay nh nh v, kiem tra loi, yeu cau truyen lai va dch vu bao nhan tin. no hau nh c ket hp chung vi mang tai lp Network va transport trong mo hnh OSI.



Chng nay mo ta bo giao thc thng gap va bo giao thc khac .Ngoai cac bo giao thc con co phan trnh bay ve lp giao thc van chuyen mang: Viec chon la giao thc truyen tai thong tin th tuy theo loai mang s dung la tokenring hay inthernet ma ta s dung cac bo giao thc khac nhau. Hien nay hau nh s dung cac kieu au mang theo chuan Inthernet. Cac giao thc chuan bao gom DLC, appleTalk, IPX, TCP/IP, NFS, SMB ). + NWLink: phien ban giao thc IPX/SPX cua Microsoft m rong lop van chuyen va lp mang + NetBEUI: thiet ke cho mang cua Microsoft. NetBEUI gom mang va van chuyen no khong dan c nen khong dung het kha nang cua lp mang + ATP va NBT: la cac lp giao thc van chuyen cua AppleTalk. + Data link control (DLC): giao thc nay ket noi voi may chu IBM va may in - Noi them ve inthernet network : Ethernet network la nh c phan cng va tieu chuan ghep noi mang cuc bo do hang Xerox Corporation a ra. No co kha nang lien ket len en 1024 nut mang trong 1 mang bus, inthernet cho phep truyen tai d lieu dang day vi toc o 10Mbs vi bang thong thc te t 2 3 Mbps. Ethernet s dung 1 ky thuat tham nhap cac iem noi = viec cam nhan song mang co do xung ot e e phong truc trac cho mang khi co 2 thiet b cung tham nhap mang I. TCP/IP GIAO THC INTERNET Bo giao thc TCP/IP ( giao thc chuan cua internet ) c phat trien bi bo quoc phong My nham phuc vu cho 1 he thong mang ln c ket noi vi nhau bi nhieu may tnh khac nhau. Muc nh nham cung co cho he thong phong thu tr nen manh me, oc lap. Noi cach khac he giao thc TCP/IP c xem nh 1 chieu thc phong thu mi cua bo quoc phong My. Nhng nam gan ay internet tr nen pho bien va c dung rong rai. TCP/IP tr nen la 1 chuan m rong pho bien e ket noi mang may tnh. ( Khong nh cac chuan IPX/SPX, DNA, SNA hoac AppleTalk tat ca nhng giao thc tren eu c quan ly bi nhng cong ty rieng) Ly do chnh la khong co 1 ai s hu no do o no c ho tr bi nhieu hang khac may tnh ln. Hau het cac nhan hieu may tnh ln eu ho tr giao thc TCP/IP.



Hnh ve cho ta biet moi quan he gia giao thc TCP/IP va mo hnh OSI. Lu y la mo hnh nay chung ta khong thay cha giao thc cho lp Data link va lp physical. Lp Data link va physical cua giao thc TCP/IP hoan toan tng thch vi lp Data link va physical mo hnh tham chieu OSI. Do bo giao thc TCP/IP c phat trien trc khi mo hnh OSI c nh ngha do o so vi mo hnh OSI ch1ng ta ch thay no co 4 lp nhng no van thc ay u chc nang nh mo hnh OSI. T mo hnh DoD nay chung ta co the thay c moi quan he gia cac lp cua mo hnh DoD nh sau : + Lp Network Access phu hp vi 2 lp cuoi cua mo hnh OSI. S phu hp nay cho phep DoD cung ton tai hien hanh vi cac chuan cho lp Data link va physical.



+ Lp Internet tng ng nh lp Network trong mo hnh OSI. Giao thc lp nay cho phep di chuyen d lieu gia cac thiet b tren mang. + Lp Host to Host tung ng vi lp Transport trong mo hnh OSI. Giao thc Host to Host cho phep cac may tram co the lien lac vi nhau tren mang tng tac ( Vao thi iem ma giao thc TCP/IP ra i th cha co khai niem ve may chu va may tram ket qua la tat ca cac may tnh noi mang eu c xem nh la ngang hang nhau. Tat ca cac may tren mang eu la may chu ) + Lp Process/ Application bao gom chc nang cua cac lp Session, Presentation, Application trong mo hnh OSI. Giao thc tai lp nay phuc vu cho cac dch vu mang. 1 so cac giao thc c ket hp s dung vi TCP/IP. Nhng giao thc nay c nhom thanh cac nhom sau : + General TCP/IP Transport protocols + TCP/IP services + TCP/IP Routing

A CH TRONG TCP/IP

a/ Thanh phn cau hnh ca a ch IP a ch IP ang c s dng hin ti (IPv4) 32 bit chia thanh 4 Octet (

mi Octet co 8 bit, tng ng 1 byte )cach m u t trai qua phi bt 1 cho n bt 32, moi Octet cach bit nhau bng du chm (.), bao gm co 3 thanh phn chnh.

Bit 1................................................................................... 32 Bit nhn dng lp ( Class bit ) a ch ca mng ( Net ID ) a ch ca may ch ( Host ID ).

+ a ch Internet biu hin dng bit nh phan : x y x y x y x y. x y x y x y x y. x y x y x y x y. x y x y x y x y x, y = 0 hoc 1.



V d:

+ a ch Internet biu hin dng thp phan : xxx.xxx.xxx.xxx

x la s thp phan t 0 n 9 V d: 146. 123. 110. 224 e n gian trong viec anh so a ch IP ngi ta khong s dung cach

anh a ch IP bang cac so nh phan v cac so nay qua kho nh ma ngi ta s dung cac so thap phan e the hien a ch IP, May se t ong chuyen oi t dang thap phan sang dang nh phan.

b/ 1 so khai niem va thuat ng lien quan :

+ a ch host: La a ch IP dung e at cho cac giao dien cua cac host (vd: at cho card mang) 2 host nam cung 1 mang se co cung network ID va khac nhau ve host ID.

+ a ch mang ( Network address ): La a ch dung e at cho giao dien cua cac host. Phan host ID la cac a ch 0. vd : 111.0.0.0

+ Mat na mang con ( subnet mask ): La 1 con so dai 32 bit, la phng tien giup may tnh xac nh c a ch mang cua 1 a ch IP bang cach AND gia a ch IP vi mat na mang con e phuc vu cho cong viec nh tuyen c / Cac lp a ch IP a ch IP chia ra 5 lp A,B,C, D, E. Hin ti ang s dung ht lp A,B va gn ht lp C, con lp D va E T chc internet ang danh cho mc ch khac nen khong phan, do o chung ta ch nghien cu 3 lp A, B, C.

Lp A bao gom 8 bit au tien la NetID, 24 bit tiep theo la HostID. e nhan

dien lp A bit au tien la bit 0.



Nh vay lp A co 8 bit lam NetID tr i 1 bit e nhan dang lp con lai 2 NetID = 128. Trong o 2 trng hp ac biet la a ch 0 khong s dung va a ch 127 la a ch boardcast. Ket qua lp A ch con lai 126 a ch mang t 1.0.0.0 en 126.0.0.0 va co 2 HostID = 16777214

Lp B bao gom 16 bit au tien la NetID, 16 bit tiep theo la HostID. e

nhan dien lp B la 2 bit au tien la bit 10 Nh vay lp B co 16 bit lam NetID tr i 2 bit e nhan dang lp con lai 2

NetID = 16382. mang t 128.0.0.0 en 191.255.0.0 va co 2 HostID = 65534 (sau khi tr i 2 trng hp ac biet)

Lp C bao gom 24 bit au tien la NetID, 8 bit tiep theo la HostID. e nhan

dien lp A la 2 bit au tien la bit 110. Nh vay lp C co 24 bit lam NetID tr i 3 bit e nhan dang lp con lai 2

NetID = 2097150 mang t 192.0.0.0.0 en 223.255.255.0 va co 2 HostID = 254 (sau khi tr i 2 trng hp ac biet)

Lp D co 4 bit u tien nhn dng la 1110, lp E co 5 bt u tien nhn dng la 11110. a ch nam trong khoang t 224 255. Cac lp nay



khong phuc vu cho viec anh a ch host ch phuc vu cho vec nghien cu va d phong nen khong trnh bay trong tai lieu nay. Bang thong so a ch IP cua cac lp

a ch lp

Vung a ch ly thuyt

Vung a ch s dng

Subnet mask S mng ti a s dng

S host ti a tren tng mng

Bit nhn dng

A 0.0.0.0 - 127.0.0.0 1 - 126 255.0.0.0 126 16777214

0

B 128.0.0.0 - 191.255.0.0

128 191 255.255.0.0 16382 65534 10

C 192.0.0.0 - 223.255.255.0

192 - 223 255.255.255.0

2097150 254 110

D 224.0.0.0 - 240.0.0.0 1110 E 241.0.0.0 - 255.0.0.0 11110 V du : Class IP Address Network ID Host ID Subnet mask Class A 102.44.7.100 102.0.0.0 X.44.7.10 255.0.0.0 Class B 131.107.4.6 131.107.0.0 X.X.4.6 255.255.0.0 Class C 200.9.88.250 200.6.88.0 X.X.X.250 255.255.255.0

ieu cuoi cung e co kien thc khi thao luan a ch IP la d kien ma moi

thiet b mang o la moi may tnh, may in, bo nh tuyen hay bat c thiet b nao khac co the c gan rieng can mot a ch IP duy nhat. Noi theo cach khac, moi thiet b tr6en he thong mang can mot a ch IP va khong co hai a ch IP giong nhau tren mot mang.

Internet Protocol (IP): Giao thc Internet (IP) la mot giao thc ket noi ma no cung cap dch vu

gam d lieu va goi tin IP thng c xem la gam d lieu IP. IP la mot giao thc



chuyen goi tin thc hien qua trnh chon a ch va nh tuyen ng i. Phan au IP c gan vao goi tin no c truyen i theo dang giao thc cap thap. IP nh tuyen cho cac goi tin qua mang tng tac bang cach s dung bang nh tuyen tham chieu tai moi bc nhay. Viec xac nh tuyen ng bang cach tham khao thong tin thiet b mang vat ly, logic va c cung cap bi giao thc phan giai a ch Address Resolution Protocol (ARP).

IP thc hien phan oan va rap lai cac goi tin theo gii han, kch c goi tin c nh bi lp vat ly va lien ket d lieu thc hien. IP cung cho phep kiem tra loi phan au d lieu bang tong kiem tra mac du lp d lieu cao hn khong c kiem tra.

Transmission Control Protocol (TCP) : Giao thc ieu khien phien truyen (TCP) la mot giao thc nh hng ket

noi tng ng vi lp van chuyen (Transport) cua OSI. TCP cung cap dch vu ket noi song cong, au cuoi cham nhau. Khi khong can s dung thong tin bao nhan gia nhng au mut th giao thc gam d lieu ngui dung User Datagram Protocol (UDP) co the c thay the cho TCP mc truyen tai host to host, TCP va UDP hoat ong tren cung mot lp.

TCP tng ng vi SXP trong moi trng Netware (xem phan Netware IPX/SPX).TCP duy tr hp ly ket noi gia he thong may gi va may nhan. Bao am tnh toan ven cua d lieu truyen. TCP do tm nhanh bat c van e nao trong viec chuyen giao va lam viec sa cha no. Ngc lai, TCP khong chay nhanh bang UDP do viec xac nhan thong tin cac may a gi.

TCP cung cung cap va tha nhan thong iep phan manh va rap lai, no co the chap nhan thong iep vi bat ky chieu dai nao t cac giao thc lp cao hn. TCP phan oan dong thong iep c ieu khien bi IP. Qua trnh nay c ng dung e chia d lieu ra thanh khoi nho hn. IP van co the phan oan cho goi tin UDP va manh hn oi vi goi tin TCP. Khi dung IP, TCP cong them dch vu ket noi nh hng va thc hien phan oan ong bo hoa, them cac so trnh t cac mc byte.

Trong viec phan oan goi tin, TCP co the ket hp nhieu cuoc thoai vi cac lp giao thc cao hn va co the cai thien lam cho bang thong nay tot hn bang cach noi nhieu thong iep vao cung phan oan. Moi ket noi mach ao c gan cho mot nhan dang ket noi goi la cong dung e nh danh viec ket hp gam d lieu vi cac ket noi o.

User Datagram Protocol (UDP):



Giao thc gam d lieu ngi dung la mot giao thc khong ket noi phien truyen (lien may chu). UDP khong cung cap tin bao nhan thong iep, no n gian hn la ch truyen tai d lieu, UDP s dung a ch e phan phoi gam d lieu. Tuy nhien, a ch UDP c u tien hn TCP. Khi van hanh chung mang viec truyen nhanh hay cham c quan tam hn la kha nang ban giao ang tin cay. Bi v UDP khong can thiet lap, duy tr va ong cac ket noi, ieu khien luong d lieu nen kha nang truyen tai nhanh hn TCP. iem yeu cua UDP la no thc hien khong tin cay nh la TCP khi truyen d lieu, do o UDP thng c dung khi truyen d lieu vi lng nho.

UDP la giao thc tang transport c dung vi SNMP(Simple network managerment protocol) chuan giao thc quan ly mang nay c dung vi mang TCP/IP, UDP cho phep SNMP cung cap s quan ly mang mc toi thieu. Address Resolution Protocol (ARP): Giao thc phan giai a ch

Co ba loai a ch c dung tren mang TCP/IP: a ch vat ly: c dung bi tang vat ly va tang lien ket d lieu. a ch IP: cung cap mang logic va ID cua may. a ch IP nay gom bon so

bieu dien dang thap phan co cham. Ten logic: xac nh va nhan dien may theo ten may, no giup cho ngi

dung de oc hn la ten a ch IP. V du ve ten logic nh MAYCCS Khi cho mot a ch IP, giao thc phan giai a ch ARP co the xac nh a

ch vat ly c s dung bi thiet b co a ch IP o. ARP duy tr bang d lieu phan giai a ch va phat tan goi tin e kham pha cac a ch trong phan oan mang hay s dung bo nh em trc o. a ch vat ly c kham pha bi ARP co the cung cap cho giao thc lp lien ket d lieu (data link). Tat ca cac a ch trong bang ARP ch la a ch cuc bo. Nhng a ch nao khong phai a ch cuc bo trong tuyen th khong co kha nang try xuat en nhng a ch cuc bo

Internet Control Message Protocol (ICMP):

Giao thc tao thong iep ieu khien ket noi mang (ICMP) tang cng ieu khien loi do IP cung cap. Giao thc khong ket noi nh IP, khong do tm loi tren mang tng tac nh tat nghen hay ng dan khong thch hp. ICMP co the tm loi card mang, thong bao cho IP va giao thc lp cao hn. Mot card mang ma no co loi thng truyen thong iep ti cac card mang khac thong qua mot goi tin ICMP.



TCP/IP SERVICES: oan nay tap trung vao mot so dch vu TCP/IP ton tai trong he giao thc TCP/IP. Nhng dch vu nay ch la mot vai trong so nhng dch vu pho bien khi ban giao tiep vi mang Microsoft.

Dynamic Host Configuration Protocol (DHCP): Giao thc cau hnh IP ong

Khi phan a ch IP co the gan a ch IP va mat na mang con mot cach thu cong ti moi may tnh tren mang. Giao thc DHCP cho phep t ong ch nh a ch IP. ieu nay thng c thc hien bi mot hoac nhieu may tnh (may chu DHCP) cung cap viec gan a ch IP va mat na mang con cho cac may tnh khac tren 1 oan mang. Moi lan khi chay e lam viec vi mang, may tnh se c may cung cap DHCP cap cho 1 a ch IP va subnet mask mi. Hau het thiet b nh tuyen eu c cau hnh khong cho phat tan ban tin i qua thiet b. Do o can co mot may chu DHCP e cap IP ong cho moi phan oan. Mot trong nhng kha nang e co the thay may chu DHCP trong moi phan oan bang cach tren moi phan oan co mot tram chuyen tiep DHCP e no chuyen yeu cau phat tin xin a ch IP cua may khach ve may chu DHCP tren mot phan oan khac.

Domain Name System (DNS): Giao thc he thong ten mien (DNS) cung cap ten may va giai ma a ch IP nh mot dch vu ng dung may khach. May chu DNS cho phep ngi s dung dung cac ten logic cua may ( ten ay u ) e truy xuat tai nguyen mang. Ten may co the dai ti 260 ky t.

Windows Internet Naming Services (WINS): Dch vu at ten mang theo Windows (WINS) cung cap chc nang tng t

nh cua DNS. No cung cap ten NetBIOS e phan giai a ch IP. ieu nay quan trong bi v tat ca cac mang cua Microsoft yeu cau kha nang tham chieu ten NetBIOS. Thong thng ten NetBIOS co c cung vi viec phat tin nhng v Router thng khong cho phep phat tin qua no. Mot WINS sever la mot giai phap e co the dung e thay the a ch IP e ap ng cac yeu cau ten NetBIOS.

File Transfer Potocol (FPT): Giao thc thc truyen tai tap tin (FPT) la mot giao thc cho phep truyen tai tap tin gia cac may noi mang. FPT cho phep ngi ang nhap vao may t xa.



Ngi dung ang nhap co the kiem tra th muc, van dung cac tap tin, thi hanh lenh va thc hien lenh khac tren may.

Simple Mail Transfer Protocol(SMTP) Giao thc chuye th n gian la mot giao thc cho dan ng th tn tren

mang.SMTP s dung cac giao thc TCP vaIP. SMTP khong cung cap giao dien th tn cho ngi dung, s sang tao ,quan ly va phan phoi cac thong iep en ngi dung cuoi c thc hien bang cac ng dung ve th tn.

Remote Terminal Emulation(TELNET) TELNET la mot giao thc mo phong thiet b cuoi .TELNET cho phep may tnh ca nhan va tram may hoat ong nh mot tram cuoi trong phien lam viec vi may chu tren mang .Viec thc hien TELNET san co nen tang may s dung lam tram cuoi.Ke ca UNIX,DOS,Windows va he ieu hanh Macintosh OS. Network File System(NFS) (He thong tap tin mang ) He thong tap tin mang (NFS),c phat trien bi Sun Microsystems la mot ho giao thc truy cap tap tin, co nhieu tien bo ang ke so vi FTP va TELNET. Bi v SUN lam cho cac chc nang NFS dung chung c va NFS a at c mc pho bien cao.NFS bao gom co 2 giao thc: eXternal Data Representation (XDR) : Ho tr viec ma hoa d lieu theo mot nh dang oc lap vi phan cng. Chng trnh C dung thu tuc th vien XDR e mo ta cac cau truc d lieu gia cac moi trng may ca nhan. Remote Procedure call (RPC Goi thu tuc t xa): Cac chc nang nh nh hng lai yeu cau dch vu, xac inh mot li goi ham thoa man mc cuc bo hay phai nh hng lai vi mot may chu xa . Cac li goi ti may xa c ong goi e van chuyen qua mang va truyen ti cac may RPC, thong thng co kha nang phuc vu nhieu yeu cau phuc vu xa .May RPC gi yeu cau dch vu va tao ra cac goi tin tra li c tra ve ni a yeu cau dch vu. TCP/IP Routing Protocols (Giao thc dan ng TCP/IP) Phan ke tiep se trnh bay hai loai giao thc dan ng pho bien nhat c TCP/IP s dung Routing Information Protocol(RIP) Giao thc thong tin dan ng(RIP) trong bo giao thc giong TCP/IP khong phai la giao thc giong RIP trong bo giao thc NetWare,mac du ca hai ieu phuc



vu nhng chc nang tng t. Internet RIP tm ng dan bang mot phng phap c ly vector, tnh toan so chang ng phai i qua e dan ng cho mot goi tin. Mac du no lam viec tot trong cac mang cuc bo nhng RIP the hien nhieu yeu iem lam gii han kha nang s dung cua no tren cac mang dien rong .Chan han nh phng phap tm ng qua c ly vector cua RIP oi nhieu thong bao hn va v vay tao ra nhieu giao thong tren mang hn mot so phng phap khac. toan ban lo trnh cung c gi i kem theo thong bao tao ra lng lu thong ln khi bang lo trnh ln len. Giao thc OSPF, s dung phng phap tm ng qua trang thai ket noi,ang dan thay the cho RIP Open Shorest Path First (OSPF) (M ng dan ngan nhat trc) Giao thc OSPF la mot giao thc tm ng qua trang thai ket noi c thiet ke e khac phuc s gii han cua RIP.Trong cac mang ln OSPF co the xac nh c cau truc lien ket mang va cai thien hieu nang can bang tai va dan ng theo phan loai dch vu. II. NETWARE IPX/SPX Cac giao thc dung vi mang NetWare c tong ket trong hnh 7.4.Cac giao thc NetWare c thiet ke mo un cao.Kha nang ieu hp nay khien cho cac giao thc NetWare phu hp vi nhieu phan cng khac nhau va n gian hoa nhiem vu ket hp vi cac iao thc khac nhau trong bo giao thc.Windows NT khong s dung bo IPX/SPX e giao tiep vi nhng tai nguyen cua IPX/SPX goi la NWLink-truyen tng thch vi IPX/SPX,no thn nho gon va nhanh hn TCP/IP va cung giong nh TCP/IP,no cung dan ng c.Tuy nhien no hoat ong yeu hn lp lien ket d lieu trong mo hnh OSI,do o no oc lap ve thiet b phan cng hn so vi giao thc TCP/IP.



General IPX/SPX Transport Protocols (Cac giao thc truyen IPX/SPX thong dung) Cac phan tiep theo se noi en cac giao thc trong bo giao thc trong bo giao thc IPX/SPX. Lien qua en cac lp mang va van chuyen cua mo hnh OSI . Addressing in IPX (anh a ch theo IPX) Viec anh a ch trong IPX/SPX(NWLink) th n gian hn han so vi TCP/IP. IPX/SPX cung co hai loai a ch phan biet: mot a ch may va mot a ch mang. a ch host trong IPX/SPX da tren a ch phan cng cua card mang. Cac a ch nay ve ban chat la cac he thap luc phan, Cac a ch s dung bi card mang c IEE phan phoi. Thong thng hai so au tien trong ba bo so e ch nha san xuat card ieu hp mang o.Sau ay la hai v du ve cac loai a ch nay: 44-45-53-54-00-00 07-00-4d-55-64-3e oi vi cac a ch mang, a ch logic nay c nh bi nha quan tr. Thong thng khi mot sever hay route c cai at, a ch mang do nha quan tr mang nh ra.a ch mang logic nay co 8 ch so thap luc phan.Sau ay la mot vai v du: 903E0467 BEEF0000 E8012000.



Tong quat cac a ch trong IPX/SPX thng c bieu dien di dang a ch may chu:a ch mang,nh sau: Vd : 55-66-00-e4-7a:E8022000 a ch nay ai dien cho may chu 55-66-00-e4-7a tren mang E8022000. IPX(Internetwork Packet Exchange Protocol) Giao thc trao oi goi tin mang (IPX)la mot giao thc lp mang(network) cung cap cac dch vu gram d lieu (datagram).(IPX c phat trien t giao thc XNS do hang Xero tao ra). IPX chu trach nhiem dan ng qua mang va duy tr cac a ch logic mang. Viec dan ng dung giao thc RIP(se c noi en trong phan sau nay)e la chon ng i.IPX co cac chc nang tng t nh nhng g UDP thc hien trong bo giao thc TCP/IP. IPX da vao a ch vat ly cua phan cng thay cac lp thap hn ,e cung cap a ch cua cac thiet b mang. IPX cung dung cac sockets hay cac a ch dch vu lp cao hn e chuyen giao cac goi tin en mot ch duy nhat. Ve pha client, IPX a ho tr cac thanh phan DOS Sehll cu va NetWare hien thi. IPX cung cap cac chc nang tng t nh UDP trong bo giao thc TCP/IP. SPX(Sequenced Packet Exchange) SPX la mot giao thc lp van chuyen giup m rong

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