{"id":544,"date":"2020-04-07T18:48:30","date_gmt":"2020-04-07T16:48:30","guid":{"rendered":"http:\/\/tech.sosthe.sk\/?p=544"},"modified":"2020-04-12T18:24:51","modified_gmt":"2020-04-12T16:24:51","slug":"3-osi-model","status":"publish","type":"post","link":"http:\/\/tech.sosthe.sk\/index.php\/2020\/04\/07\/3-osi-model\/","title":{"rendered":"3. OSI model"},"content":{"rendered":"

Popis\u00a0OSI modelu<\/strong><\/em>\u00a0vznikol u\u017e pred radom rokov a napriek tomu, \u017ee sa pova\u017euje za z\u00e1klad pre sie\u0165ov\u00e9 technol\u00f3gie, tak nebol nikdy presne realizovan\u00fd.\u00a0Obdobou OSI modelu je\u00a0TCP\/IP<\/strong> , u ktor\u00e9ho m\u00f4\u017eeme poveda\u0165, \u017ee vych\u00e1dza z OSI modelu, ale upravuje ho, aby bol viac flexibiln\u00fd. Pod\u013ea OSI modelu<\/strong><\/em>\u00a0je v\u017edy mo\u017en\u00e9 komunikova\u0165 iba s vrstvou nad alebo pod.\u00a0A v\u0161etky vrstvy musia by\u0165 v komunik\u00e1cii obsiahnut\u00e9, \u010do v rade praktick\u00fdch \u00faloh prin\u00e1\u0161a zbyto\u010dn\u00fa z\u00e1\u0165a\u017e (\u010dasov\u00fa i d\u00e1tov\u00fa).\u00a0Napriek tomu je OSI model dobr\u00fd pre interpret\u00e1ciu a teoretick\u00fd opis siet\u00ed.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n
<\/td>\nvrstva AJ<\/span><\/strong><\/td>\nvrstva SK<\/span><\/strong><\/td>\njednotka<\/span><\/strong><\/td>\nfunkcie vrstvy<\/span><\/strong><\/td>\npr\u00edklad<\/span><\/strong><\/td>\n<\/tr>\n<\/thead>\n
layer 7<\/strong><\/span><\/td>\nApplication<\/span><\/td>\nAplika\u010dn\u00e1<\/span><\/td>\nd\u00e1ta<\/span><\/td>\nSie\u0165ov\u00e9 procesy pre aplik\u00e1ciu, overenie pou\u017e\u00edvate\u013eov, v\u0161etko z\u00e1visl\u00e9 na aplik\u00e1ciu.<\/span><\/td>\nTelnet, FTP<\/span><\/td>\n<\/tr>\n
layer 6<\/strong><\/span><\/td>\nPresentation<\/span><\/td>\nPrezenta\u010dn\u00e1<\/span><\/td>\nd\u00e1ta<\/span><\/td>\nReprezent\u00e1cia d\u00e1t a \u0161ifrovanie.\u00a0Rie\u0161i rozdiely v reprezent\u00e1cii d\u00e1t medzi aplik\u00e1ciou a sie\u0165ov\u00fdm form\u00e1tom – k\u00f3duje d\u00e1ta pre prenos.<\/span><\/td>\nMIDI, MPEG<\/span><\/td>\n<\/tr>\n
layer 5<\/strong><\/span><\/td>\nSession<\/span><\/td>\nRela\u010dn\u00e1<\/span><\/td>\nd\u00e1ta<\/span><\/td>\nSpojenie medzi aplik\u00e1ciami, spr\u00e1va session.\u00a0Komunik\u00e1cia jednej aplik\u00e1cie s druhou, posielanie viac d\u00e1t po sebe.\u00a0Udr\u017euje cel\u00e9 spojenie medzi dvoma po\u010d\u00edta\u010dmi.<\/span><\/td>\nNetBIOS<\/span><\/td>\n<\/tr>\n
layer 4<\/strong><\/span><\/td>\nTransport<\/span><\/td>\nTransportn\u00e1<\/span><\/td>\nSegments (segmenty)<\/span><\/td>\nEnd-to-end spojenie syst\u00e9mov, spo\u013eahlivos\u0165 – zais\u0165uje kompletn\u00fa prenos d\u00e1t, kvalita slu\u017eby.\u00a0Rie\u0161i spo\u013eahliv\u00e9 odoslanie v\u0161etk\u00fdch d\u00e1t zo zdroja do cie\u013ea pomocou segment\u00e1cie a potvrdzovanie.<\/span><\/td>\nTCP, UDP<\/span><\/td>\n<\/tr>\n
layer 3<\/strong><\/span><\/td>\nNetwork<\/span><\/td>\nSie\u0165ov\u00e1<\/span><\/td>\nPackets (pakety)<\/span><\/td>\nLogick\u00e1 adres\u00e1cia – routovanie – ur\u010denie cesty paketu, prenos d\u00e1t z bodu do bodu, pou\u017e\u00edva IP adresy.\u00a0Komunik\u00e1cia medzi zdrojov\u00fdm a cie\u013eov\u00fdm zariaden\u00edm pomocou IP adresy.<\/span><\/td>\nIP, ICMP, ARP, RIP<\/span><\/td>\n<\/tr>\n
layer 2<\/strong><\/span><\/td>\nData Link<\/span><\/td>\nLinkov\u00e1<\/span><\/td>\nFrames (r\u00e1mce)<\/span><\/td>\nFyzick\u00e1 adres\u00e1cia, MAC – media access control a LLC – logical link control, d\u00e1tov\u00fd tok, synchroniz\u00e1cia r\u00e1mov, komunik\u00e1cia 1 hop, pou\u017e\u00edva MAC adresy.\u00a0Detekcia ch\u00fdb, riadenie toku a pr\u00edstupu na m\u00e9dium.\u00a0Komunik\u00e1cia medzi dvoma zariadeniami v jednom subnetu (alebo na br\u00e1nu) pomocou MAC adresy.\u00a0Vytv\u00e1ra r\u00e1mca (hlavi\u010dka + d\u00e1ta + p\u00e4ta).<\/span><\/td>\nEthernet, FDDI, Token Ring, PPP, SLIP<\/span><\/td>\n<\/tr>\n
layer 1<\/strong><\/span><\/td>\nPhysical<\/span><\/td>\nFyzick\u00e1<\/span><\/td>\nBits (bity)<\/span><\/td>\nFyzick\u00e9 parametre linky – m\u00e9dia (k\u00e1ble, r\u00e1dio, svetlo), sign\u00e1ly a bin\u00e1rne prenos.\u00a0Rie\u0161i fyzickej poslanie d\u00e1t (pren\u00e1\u0161an\u00fdm bitom neprira\u010fuje \u017eiadny v\u00fdznam).<\/span><\/td>\n100BaseT, RS-232, 802.11g<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Porovnanie OSI vs.\u00a0TCP \/ IP<\/h3>\n

V praktickom pr\u00edpade a hlavne, ke\u010f pou\u017e\u00edvame protokol TCP\/IP, m\u00f4\u017eeme pou\u017ei\u0165 TCP\/IP model. Hrub\u00e9 porovnanie s ISO OSI modelom je tu.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n
TCP \/ IP<\/td>\nOSI<\/td>\n<\/tr>\n<\/thead>\n
Aplika\u010dn\u00e1<\/span><\/td>\nAplika\u010dn\u00e1<\/span><\/td>\n<\/tr>\n
Prezenta\u010dn\u00e1<\/span><\/td>\n<\/tr>\n
Rela\u010dn\u00e1<\/span><\/td>\n<\/tr>\n
Transportn\u00e1<\/span><\/td>\nTransportn\u00e1<\/span><\/td>\n<\/tr>\n
Sie\u0165ov\u00e1<\/span><\/td>\nSie\u0165ov\u00e1<\/span><\/td>\n<\/tr>\n
Vrstva sie\u0165ov\u00e9ho rozhrania<\/span><\/td>\nLinkov\u00e1<\/span><\/td>\n<\/tr>\n
Fyzick\u00e1<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

Popis\u00a0OSI modelu\u00a0vznikol u\u017e pred radom rokov a napriek tomu, \u017ee sa pova\u017euje za z\u00e1klad pre sie\u0165ov\u00e9 technol\u00f3gie, tak nebol nikdy presne realizovan\u00fd.\u00a0Obdobou OSI modelu je\u00a0TCP\/IP…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12],"tags":[],"_links":{"self":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/posts\/544"}],"collection":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/comments?post=544"}],"version-history":[{"count":12,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/posts\/544\/revisions"}],"predecessor-version":[{"id":648,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/posts\/544\/revisions\/648"}],"wp:attachment":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/media?parent=544"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/categories?post=544"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/tags?post=544"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}