{"id":698,"date":"2020-04-13T13:07:33","date_gmt":"2020-04-13T11:07:33","guid":{"rendered":"http:\/\/tech.sosthe.sk\/?page_id=698"},"modified":"2020-04-13T13:07:33","modified_gmt":"2020-04-13T11:07:33","slug":"aktivne-sietove-prvky","status":"publish","type":"page","link":"http:\/\/tech.sosthe.sk\/index.php\/sietove-technologie\/aktivne-sietove-prvky\/","title":{"rendered":"Akt\u00edvne sie\u0165ov\u00e9 prvky"},"content":{"rendered":"

Po\u010d\u00edta\u010dov\u00e1 sie\u0165<\/span><\/em><\/strong>\u00a0sa sklad\u00e1 z akt\u00edvnych a pas\u00edvnych sie\u0165ov\u00fdch prvkov.\u00a0Medzi<\/span>\u00a0pas\u00edvne sie\u0165ov\u00e9 prvky<\/span><\/em><\/strong>\u00a0patr\u00ed kabel\u00e1\u017e a konektory.\u00a0Medzi<\/span>\u00a0akt\u00edvne sie\u0165ov\u00e9 prvky<\/span><\/em><\/strong>\u00a0patr\u00ed sie\u0165ov\u00e1 karta (NIC), switch, router, firewall, a pod.<\/span><\/p>\n

Repeater (opakova\u010d)<\/span><\/h4>\n
    \n
  • pracuje na prvej vrstve OSI modelu (Layer 1)<\/span><\/li>\n
  • v\u00e4\u010d\u0161inou m\u00e1 iba dva porty<\/span><\/li>\n
  • sl\u00fa\u017ei na pred\u013a\u017eenie dosahu sign\u00e1lu, hlavne u zbernicovej topol\u00f3gie<\/span><\/li>\n
  • dnes sa nepou\u017e\u00edva<\/span><\/li>\n<\/ul>\n

    princ\u00edp funkcie<\/span><\/strong><\/p>\n

      \n
    • d\u00e1ta, ktor\u00e9 prijme na jednom porte, elektricky obnov\u00ed a okam\u017eite preposiela na druh\u00fd port<\/span><\/li>\n<\/ul>\n

       <\/p>\n

      Hub (rozbo\u010dova\u010d)<\/span><\/h4>\n
        \n
      • ozna\u010duje sa aj ako multipoint repeater<\/span><\/li>\n
      • pracuje na prvej vrstve OSI modelu (Layer 1)<\/span><\/li>\n
      • v\u00e4\u010d\u0161inou m\u00e1 4 – 24 portov<\/span><\/li>\n
      • z\u00e1kladn\u00fd prvok pre hviezdicov\u00fa topol\u00f3giu<\/span><\/li>\n
      • dnes sa nepou\u017e\u00edva<\/span><\/li>\n<\/ul>\n

        princ\u00edp funkcie<\/span><\/strong><\/p>\n

          \n
        • d\u00e1ta, ktor\u00e9 prijme na jednom porte, okam\u017eite preposiela na v\u0161etky porty okrem portu odkia\u013e ich prijal<\/span><\/li>\n<\/ul>\n

           <\/p>\n

          Bridge (most)<\/span><\/h4>\n
            \n
          • pracuje na druhej vrstve OSI modelu (Layer 2) – rozhoduje pod\u013ea MAC adresy<\/span><\/li>\n
          • v\u00e4\u010d\u0161inou m\u00e1 iba dva porty<\/span><\/li>\n
          • sl\u00fa\u017ei k prepojeniu \/ oddeleniu segmentov<\/span><\/li>\n
          • zni\u017euje ve\u013ekos\u0165 kol\u00edznej dom\u00e9ny<\/span><\/li>\n
          • Broadcast a multicasty sa posielaj\u00fa v\u0161ade<\/span><\/li>\n
          • dnes sa u\u017e nepou\u017e\u00edva<\/span><\/li>\n<\/ul>\n

            princ\u00edp funkcie<\/span><\/strong><\/p>\n

              \n
            • u prich\u00e1dzaj\u00facich r\u00e1mcov \u010d\u00edta zdrojov\u00fa MAC adresu a vytv\u00e1ra v pam\u00e4ti tabu\u013eku MAC adries a portov, odkia\u013e poch\u00e1dza<\/span><\/li>\n
            • pokia\u013e nem\u00e1 pre cie\u013eov\u00fa MAC adresu z\u00e1znam, tak r\u00e1mec odo\u0161le na v\u0161etky porty<\/span><\/li>\n
            • ak z\u00e1znam existuje a ak le\u017e\u00ed pr\u00edjemca v rovnakom segmente ako odosielate\u013e, tak sa d\u00e1ta neposielaj\u00fa do ostatn\u00fdch segmentov<\/span><\/li>\n<\/ul>\n

               <\/p>\n

              Switch (prep\u00edna\u010d)<\/span><\/h4>\n
                \n
              • ozna\u010duje sa aj ako multipoint bridge<\/span><\/li>\n
              • pracuje na druhej vrstve OSI modelu (Layer 2) – rozhoduje pod\u013ea MAC adresy<\/span><\/li>\n
              • v\u00e4\u010d\u0161inou m\u00e1 4 – 48 portov<\/span><\/li>\n
              • sl\u00fa\u017ei k prepojeniu \/ oddeleniu segmentov<\/span><\/li>\n
              • zni\u017euje ve\u013ekos\u0165 kol\u00edznej dom\u00e9ny<\/span><\/li>\n
              • Broadcasty sa posielaj\u00fa v\u0161ade<\/span><\/li>\n
              • pracuje r\u00fdchlo<\/span><\/li>\n
              • z\u00e1kladn\u00fd prvok pre hviezdicov\u00fa topol\u00f3giu<\/span><\/li>\n
              • neupravuje r\u00e1mec<\/span><\/li>\n<\/ul>\n

                princ\u00edp funkcie<\/span><\/strong><\/p>\n

                  \n
                • u prich\u00e1dzaj\u00facich r\u00e1mcov \u010d\u00edta zdrojov\u00fa MAC adresu a vytv\u00e1ra v pam\u00e4ti tabu\u013eku MAC adries a portov, odkia\u013e poch\u00e1dza, tabu\u013eka sa ozna\u010duje ako CAM (Content addressable Memory) tabu\u013eka<\/span><\/li>\n
                • pokia\u013e nem\u00e1 pre cie\u013eov\u00fa MAC adresu z\u00e1znam, tak r\u00e1mec odo\u0161le na v\u0161etky porty mimo prich\u00e1dzaj\u00faceho<\/span><\/li>\n
                • ak m\u00e1 v tabu\u013eke cie\u013eov\u00fa MAC adresu, tak r\u00e1mec po\u0161le iba na dan\u00fd port<\/span><\/li>\n<\/ul>\n

                  M\u00f3dy switcha<\/span><\/h4>\n

                  Kv\u00f4li h\u013eadaniu kompromisu medzi me\u0161kan\u00edm a spo\u013eahlivos\u0165ou existuje nieko\u013eko met\u00f3d.<\/span><\/p>\n

                    \n
                  • Cut-Through<\/span><\/strong><\/em> – r\u00fdchle, ale bez kontroly ch\u00fdb, preposiela r\u00e1mce okam\u017eite, kedy pozn\u00e1 cie\u013eov\u00fa MAC adresu<\/span><\/li>\n
                  • Store-and-Forward<\/span><\/strong><\/em>\u00a0– najprv sa cel\u00fd r\u00e1mec prijme, over\u00ed sa FCS (CRC) a a\u017e potom posiela alebo zahod\u00ed<\/span><\/li>\n
                  • Fragment-Free<\/span><\/strong><\/em>\u00a0(Modified Cut-Through) – kompromis, najprv na\u010d\u00edta prv\u00fdch 64 bytov (vr\u00e1tane hlavi\u010dky) a potom preposiela<\/span><\/li>\n<\/ul>\n

                     <\/p>\n

                    Router (smerova\u010d)<\/span><\/h4>\n
                      \n
                    • pracuje na tretej vrstve OSI modelu (Layer 3) – rozhoduje pod\u013ea IP adresy<\/span><\/li>\n
                    • hrani\u010dn\u00fd router sa ob\u010das ozna\u010duje ako gateway (br\u00e1na)<\/span><\/li>\n
                    • sl\u00fa\u017ei pre sp\u00e1janie siet\u00ed<\/span><\/li>\n
                    • pon\u00faka slu\u017eby vn\u00fatri LAN (smerovanie zo zdroja do cie\u013ea, segmentovanie siete, ARP) a prepojenie do WAN (cez serial, ISDN, DSL, optiku)<\/span><\/li>\n
                    • Broadcasty sa \u0161tandardne nepreposielaj\u00fa – zni\u017euje ve\u013ekos\u0165 broadcastovej dom\u00e9ny<\/span><\/li>\n
                    • je pomal\u0161\u00ed ako switch, \u010dasto je dnes nahradzovan\u00fd Layer 3 switchom (Multilayer Switch)<\/span><\/li>\n
                    • vytv\u00e1ra nov\u00fa hlavi\u010dku a ukon\u010denie (CRC) r\u00e1mca<\/span><\/li>\n<\/ul>\n

                      princ\u00edp funkcie<\/span><\/strong><\/p>\n

                        \n
                      • v pam\u00e4ti si zostavuje routovaciu tabu\u013eku pod\u013ea siet\u00ed, kam m\u00e1 priamo pripojen\u00e9 rozhrania (interface), pod\u013ea statick\u00fdch hodn\u00f4t a pod\u013ea inform\u00e1ci\u00ed od ostatn\u00fdch routerov (z\u00e1le\u017e\u00ed na pou\u017eitom protokole)<\/span><\/li>\n
                      • pri prich\u00e1dzaj\u00facich paketov sa pozer\u00e1 na cie\u013eov\u00fa IP adresu a pod\u013ea routovacej tabu\u013eky ur\u010duje cestu k cie\u013eu (odosiela d\u00e1ta na dan\u00fd port)<\/span><\/li>\n
                      • pri odosielan\u00ed d\u00e1t modifikuje hlavi\u010dku r\u00e1mca, ako zdrojov\u00fa MAC adresu vklad\u00e1 svojou a ako cie\u013eov\u00fa bu\u010f \u010fal\u0161\u00ed router alebo stanicu<\/span><\/li>\n
                      • ak cie\u013eov\u00e1 IP adresa patr\u00ed do niektor\u00e9ho priamo pripojen\u00e9ho subnetu, tak odosiela priamo tejto stanici, pritom sa pozrie do ARP tabu\u013eky, \u010di m\u00e1 pre dan\u00fa IP adresu MAC adresu, ak nie, tak odo\u0161le ARP dotaz (kto m\u00e1 t\u00fato IP?), ak nedostane odpove\u010f, tak r\u00e1mec zahod\u00ed, ak \u00e1no, tak dopln\u00ed ARP tabu\u013eku a r\u00e1mec odo\u0161le<\/span><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

                        Po\u010d\u00edta\u010dov\u00e1 sie\u0165\u00a0sa sklad\u00e1 z akt\u00edvnych a pas\u00edvnych sie\u0165ov\u00fdch prvkov.\u00a0Medzi\u00a0pas\u00edvne sie\u0165ov\u00e9 prvky\u00a0patr\u00ed kabel\u00e1\u017e a konektory.\u00a0Medzi\u00a0akt\u00edvne sie\u0165ov\u00e9 prvky\u00a0patr\u00ed sie\u0165ov\u00e1 karta (NIC), switch, router, firewall, a pod. Repeater…<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":14,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"_links":{"self":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/pages\/698"}],"collection":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/types\/page"}],"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=698"}],"version-history":[{"count":1,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/pages\/698\/revisions"}],"predecessor-version":[{"id":699,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/pages\/698\/revisions\/699"}],"up":[{"embeddable":true,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/pages\/14"}],"wp:attachment":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/media?parent=698"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}