{"id":316,"date":"2020-04-06T00:03:07","date_gmt":"2020-04-05T22:03:07","guid":{"rendered":"http:\/\/tech.sosthe.sk\/?p=316"},"modified":"2020-04-06T16:31:44","modified_gmt":"2020-04-06T14:31:44","slug":"4-1-uloha-sietovej-vrstvy","status":"publish","type":"post","link":"http:\/\/tech.sosthe.sk\/index.php\/2020\/04\/06\/4-1-uloha-sietovej-vrstvy\/","title":{"rendered":"4.1.\u2002\u00daloha sie\u0165ovej vrstvy"},"content":{"rendered":"<p>Sie\u0165ov\u00e1 aplik\u00e1cia posiela cez soket spr\u00e1vy aplika\u010dnej vrstvy transportnej vrstve. Transportn\u00e1 vrstva del\u00ed spr\u00e1vy na men\u0161ie \u010dasti, prid\u00e1va k nim hlavi\u010dky transportnej vrstvy, \u010d\u00edm vznikaj\u00fa segmenty. Segmenty s\u00fa \u010falej odovzd\u00e1van\u00e9 sie\u0165ovej vrstve, ktor\u00e1 ku ka\u017ed\u00e9mu segmentu prid\u00e1 \u010fal\u0161iu hlavi\u010dku, \u010d\u00edm vznikne\u00a0<strong>datagram<\/strong>. Zjednodu\u0161ene sa d\u00e1 poveda\u0165, \u017ee spr\u00e1vy s\u00fa ur\u010den\u00e9 pre cie\u013eov\u00fa aplik\u00e1ciu a segment pre cie\u013eov\u00fd po\u010d\u00edta\u010d (typicky jeho opera\u010dn\u00fd syst\u00e9m) a datagram pre v\u0161etky routre (smerova\u010de) na ceste od odosielate\u013ea k pr\u00edjemcovi.<\/p>\n<p>\u00dalohou sie\u0165ovej vrstvy je dopravi\u0165 datagram od odosielate\u013ea k pr\u00edjemcovi a to \u010do mo\u017eno najefekt\u00edvnej\u0161ie, t.j. najr\u00fdchlej\u0161ou cestou. Routre s\u00fa zariadenia, ktor\u00e9 s\u00fa priamo napojen\u00e9 na viac zariaden\u00ed (\u010fal\u0161ie routre, switche, koncov\u00e9 zariadenia). Z ka\u017ed\u00e9ho z t\u00fdchto zariaden\u00ed router dost\u00e1va mnoho datagramov a jeho \u00falohou je ka\u017ed\u00fd z t\u00fdchto datagramov posla\u0165 t\u00fdm spr\u00e1vnym smerom na jeho ceste k cie\u013eovej stanici. Na to, aby router vedel, kam m\u00e1 ktor\u00fd datagram odosla\u0165, pou\u017e\u00edva\u00a0<strong>smerovaciu tabu\u013eku<\/strong>, ktor\u00e1 pre ka\u017ed\u00fa cie\u013eov\u00fa adresu ur\u010duje, ktor\u00e9mu z na\u0148ho pripojen\u00fdch zariaden\u00ed maj\u00fa by\u0165 datagramy zasielan\u00e9, presnej\u0161ie ktor\u00fdm rozhran\u00edm.<\/p>\n<p>Obsah smerovacej tabu\u013eky upravuj\u00fa\u00a0<strong>smerovacie algoritmy<\/strong>, ktor\u00e9 s\u00fa opakovane sp\u00fa\u0161\u0165an\u00e9 routrami, aby reagovali na zmeny v ich okol\u00ed (zahltenia resp. uvo\u013enenia spojen\u00ed, odst\u00e1vky in\u00fdch routrov, preru\u0161enia spojen\u00ed, vytvorenia spojen\u00ed a tak podobne) a zasielali datagramy st\u00e1le aktu\u00e1lne najlep\u0161\u00edmi smermi.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Sie\u0165ov\u00e1 aplik\u00e1cia posiela cez soket spr\u00e1vy aplika\u010dnej vrstvy transportnej vrstve. Transportn\u00e1 vrstva del\u00ed spr\u00e1vy na men\u0161ie \u010dasti, prid\u00e1va k nim hlavi\u010dky transportnej vrstvy, \u010d\u00edm vznikaj\u00fa&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"_links":{"self":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/posts\/316"}],"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=316"}],"version-history":[{"count":1,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/posts\/316\/revisions"}],"predecessor-version":[{"id":317,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/posts\/316\/revisions\/317"}],"wp:attachment":[{"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/media?parent=316"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/categories?post=316"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/tech.sosthe.sk\/index.php\/wp-json\/wp\/v2\/tags?post=316"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}