{"id":118,"date":"2009-01-27T22:29:27","date_gmt":"2009-01-27T21:29:27","guid":{"rendered":""},"modified":"2019-01-31T12:51:49","modified_gmt":"2019-01-31T11:51:49","slug":"2-spolupraca-atm-existujucich-sieti-protokolov","status":"publish","type":"post","link":"https:\/\/nil.uniza.sk\/en\/2-spolupraca-atm-existujucich-sieti-protokolov\/","title":{"rendered":"2. Spolupr\u00e1ca ATM a existuj\u00facich siet\u00ed a protokolov"},"content":{"rendered":"

2. Spolupr\u00e1ca ATM a existuj\u00facich siet\u00ed a protokolov<\/h2>\n

ATM ako sie\u0165ov\u00e1 architekt\u00fara m\u00e1 mno\u017estvo vynikaj\u00facich vlastnost\u00ed. Samozrejme, pou\u017e\u00edvate\u013e m\u00e1 z nich osoh a\u017e vtedy, ke\u010f ATM sie\u0165 re\u00e1lne vyu\u017e\u00edva. Nasadenie ATM siet\u00ed v praxi je v\u0161ak podmienen\u00e9 hlavne t\u00fdm, ako dobre sa ATM „zn\u00e1\u0161a“ s existuj\u00facimi sie\u0165ov\u00fdmi aplik\u00e1ciami. ATM sa pritom v mnoh\u00fdch aspektoch l\u00ed\u0161i od klasick\u00fdch d\u00e1tov\u00fdch siet\u00ed. Mo\u017enosti existuj\u00fa preto v z\u00e1sade dve: bu\u010f existuj\u00face aplik\u00e1cie prep\u00edsa\u0165, alebo vytvori\u0165 nejak\u00fd mechanizmus, ktor\u00fd by pracoval ako rozhranie medzi klasick\u00fdmi aplik\u00e1ciami a ATM. Prv\u00e1 mo\u017enos\u0165 je z h\u013eadiska ATM siete v\u00fdhodnej\u0161ia (nat\u00edvna ATM aplik\u00e1cia dok\u00e1\u017ee plne vyu\u017ei\u0165 schopnosti ATM technol\u00f3gie), je v\u0161ak definit\u00edvne jasn\u00e9, \u017ee v celosvetovom meradle, kde m\u00e1 absol\u00fatnu dominanciu rodina IP protokolov, je tento sp\u00f4sob nepriechodn\u00fd. Preto sa dnes pozornos\u0165 s\u00fastre\u010fuje sk\u00f4r na to, ako spoji\u0165 ATM a klasick\u00e9 sie\u0165ov\u00e9 technol\u00f3gie, aby sie\u0165ov\u00e9 aplik\u00e1cie mohli \u010falej pracova\u0165 bezo zmien.<\/p>\n

Vz\u00e1jomn\u00e9 „zbl\u00ed\u017eenie“ klasick\u00fdch sie\u0165ov\u00fdch technol\u00f3gi\u00ed a protokolov s ATM architekt\u00farou pritom m\u00f4\u017ee prebieha\u0165 dvomi sp\u00f4sobmi: bu\u010f sa existuj\u00face sie\u0165ov\u00e9 protokoly pribl\u00ed\u017eia ATM, alebo sa ATM pribl\u00ed\u017ei klasick\u00fdm sie\u0165am. Prvou cestou sa uberalo CLIP, druhou LANE.<\/p>\n

<\/a>CLIP – Classical IP over ATM<\/h3>\n

CLIP je s\u00e9ria \u0161pecifik\u00e1ci\u00ed vytvoren\u00fdch IETF, ako prisp\u00f4sobi\u0165 tok d\u00e1t v IP protokole pre prenos ATM sie\u0165ou. Tieto \u0161pecifik\u00e1cie s\u00fa „\u0161it\u00e9 na mieru“ rodine protokolov IP a z\u00e1rove\u0148 umo\u017e\u0148uj\u00fa v IP spojeniach vyu\u017e\u00edva\u0165 roz\u0161\u00edren\u00e9 schopnosti ATM siet\u00ed, napr\u00edklad kvalitu slu\u017eieb.<\/p>\n

Jedn\u00fdm zo z\u00e1kladn\u00fdch pojmov v \u0161tandardoch CLIP je<\/p>\n

LIS<\/span><\/p>\n

– Logical IP Subnet. LIS z poh\u013eadu IP protokolu je jednoducho jedna IP podsie\u0165. Z h\u013eadiska 2. vrstvy OSI modelu je LIS virtu\u00e1lnym anal\u00f3gom LAN siete, v ktorej existuje mechanizmus prekladu adries sie\u0165ovej vrstvy na adresy linkovej vrstvy. V jednej LIS patria v\u0161etky stanice do rovnakej IP siete a maj\u00fa rovnak\u00fa sie\u0165ov\u00fa masku. Viacer\u00e9 LIS medzi sebou m\u00f4\u017eu komunikova\u0165 len prostredn\u00edctvom smerova\u010dov (v z\u00e1sade je to po\u017eiadavka IP protokolu, aby medzi dvomi r\u00f4znymi IP sie\u0165ami existoval smerova\u010d), a to i v pr\u00edpade, \u017ee by sa mohli v r\u00e1mci ATM infra\u0161trukt\u00fary spoji\u0165 priamo.<\/p>\n

\u010eal\u0161\u00edm d\u00f4le\u017eit\u00fdm pojmom je<\/p>\n

ATMARP server<\/span><\/p>\n

. V klasick\u00fdch LAN sie\u0165ach je potrebn\u00e9 IP adresy mapova\u0165 na MAC adresy stan\u00edc a t\u00fato funkciu zabezpe\u010duje ARP protokol. V LIS je potrebn\u00e9 preklada\u0165 IP adresy na ATM adresy, a o tento preklad sa star\u00e1 pr\u00e1ve ATMARP server. Ten udr\u017eiava dynamick\u00fa datab\u00e1zu ATM adries po\u010d\u00edta\u010dov v LIS a ich pr\u00edslu\u0161n\u00fdch IP adries. V ka\u017edej LIS mus\u00ed existova\u0165 aspo\u0148 jeden ATMARP server.<\/p>\n

V CLIP je realiz\u00e1cia vysielania obe\u017en\u00edkov (broadcastov resp. multicastov) problematick\u00e1. Pre podporu obe\u017en\u00edkov\u00e9ho vysielania bola vytvoren\u00e1 \u0161pecifik\u00e1cia tzv.<\/p>\n

MARS servera<\/span><\/p>\n

(Multicast Address Resolution Server), ktor\u00fd sp\u00e1ja funkcionalitu klasick\u00e9ho IP multicastingu a mapovania IP multicastov\u00fdch skup\u00edn a brodcastov\u00fdch adries do mno\u017e\u00edn ATM adries.<\/p>\n

CLIP svojou relat\u00edvnou jednoduchos\u0165ou a priamo\u010diaros\u0165ou implement\u00e1cie umo\u017e\u0148uje ve\u013emi efekt\u00edvny prenos IP datagramov cez ATM infra\u0161trukt\u00faru. Ke\u010f\u017ee je dobre prisp\u00f4soben\u00fd protokolu IP, pren\u00e1\u0161a len m\u00e1lo dodato\u010dn\u00fdch inform\u00e1ci\u00ed. CLIP dovo\u013euje z\u00e1rove\u0148 vyu\u017eitie slu\u017eieb QoS v ATM.<\/p>\n

<\/a>LANE – LAN Emulation<\/h3>\n

Jednou z hlavn\u00fdch nev\u00fdhod CLIP pr\u00edstupu je, \u017ee je stavan\u00fd len pre protokol IP. Akon\u00e1hle by bolo potrebn\u00e9 cez ATM sie\u0165 pren\u00e1\u0161a\u0165 napr\u00edklad pakety protokolu IPX alebo AppleTalk, CLIP samotn\u00e9 by n\u00e1m nepomohlo. Vytv\u00e1ra\u0165 pod\u013ea vzoru CLIP analogick\u00e9 \u0161tandardy pre v\u0161etky mo\u017en\u00e9 \u010fal\u0161ie sie\u0165ov\u00e9 protokoly nie je rie\u0161enie. Preto sa v\u00fdvoj s\u00fastredil in\u00fdm smerom – na vytvorenie mechanizmov, pomocou ktor\u00fdch by ATM sie\u0165 spr\u00e1vala vo\u010di vy\u0161\u0161\u00edm sie\u0165ov\u00fdm protokolom ako klasick\u00e1 LAN. Povedan\u00e9 in\u00fdmi slovami, cie\u013eom bolo vytvorenie emul\u00e1cie siet\u00ed LAN nad sie\u0165ou ATM. Nad takouto emul\u00e1ciou by u\u017e bolo mo\u017en\u00e9 prev\u00e1dzkova\u0165 ak\u00fdko\u013evek sie\u0165ov\u00fd protokol – z jeho poh\u013eadu by sa ATM toti\u017e javila ako oby\u010dajn\u00e1 LAN sie\u0165, s ktorou nie je probl\u00e9m spolupracova\u0165. T\u00e1to emul\u00e1cia po svojom vzniku a \u0161tandardiz\u00e1cii dostala meno LANE. V s\u00fa\u010dasnosti s\u00fa \u0161tandardizovan\u00e9 dva typy LANE – typ Ethernet a typ TokenRing. L\u00ed\u0161ia sa hlavne vo form\u00e1te pren\u00e1\u0161an\u00fdch r\u00e1mcov a v niektor\u00fdch podrobnostiach smerovania pren\u00e1\u0161an\u00fdch d\u00e1t.<\/p>\n

LANE pozost\u00e1va zo \u0161tyroch hlavn\u00fdch komponentov. Prv\u00fdm je<\/p>\n

LEC<\/span><\/p>\n

– LAN Emulation Client. LEC je vlastne klient LANE siete. Pr\u00edsne po\u0148at\u00e9, LEC je logick\u00e1 \u010das\u0165 ka\u017edej stanice pracuj\u00facej v LANE, ktor\u00e1 pre t\u00fato stanicu zabezpe\u010duje pr\u00edjem a vysielanie d\u00e1t do siete LANE, mapovanie adries, a je vlastne spojovac\u00edm \u010dl\u00e1nkom – rozhran\u00edm – medzi vy\u0161\u0161\u00edmi sie\u0165ov\u00fdmi protokolmi a LANE sie\u0165ou. V praxi v\u0161ak posta\u010d\u00ed, ke\u010f sa na LEC budeme pozera\u0165 jednoducho ako na stanicu v LANE sieti.<\/p>\n

\u010eal\u0161\u00edm komponentom je<\/p>\n

LES<\/span><\/p>\n

– LAN Emulation Server. LES udr\u017eiava pre dan\u00fa LANE zoznam MAC adries a pr\u00edslu\u0161n\u00fdch ATM adries \u010dlensk\u00fdch stan\u00edc. Svojou funkciou LES pripom\u00edna ATMARP server zo \u0161tandardu CLIP. V pr\u00edpade, \u017ee LES nem\u00e1 po\u017eadovan\u00fa inform\u00e1ciu ulo\u017een\u00fa, m\u00f4\u017ee po\u017eiadavok distribuova\u0165 ostatn\u00fdm staniciam v LANE sieti. Ka\u017ed\u00fd LEC sa registruje pr\u00e1ve u jedn\u00e9ho LES. V\u0161etky LEC, ktor\u00e9 sa registrovali u rovnak\u00e9ho LES, patria do rovnakej LANE siete.<\/p>\n

Tret\u00edm komponentom LANE siet\u00ed je<\/p>\n

BUS<\/span><\/p>\n

– Broadcast and Unknown Server. ATM samotn\u00e9 nem\u00e1 nat\u00edvne prostriedky pre realiz\u00e1ciu neadresn\u00fdch alebo adresn\u00fdch obe\u017en\u00edkov (broadcasty, multicasty), v klasick\u00fdch LAN sie\u0165ach s\u00fa v\u0161ak hlavne neadresn\u00e9 obe\u017en\u00edky ve\u013emi d\u00f4le\u017eit\u00e9. V LANE zabezpe\u010duje distrib\u00faciu obe\u017en\u00edkov pr\u00e1ve BUS server, ktor\u00fd si v LES registruje MAC adresu FF:FF:FF:FF:FF:FF – t\u00fdmto sp\u00f4sobom sa na\u0148 odosielaj\u00fa v\u0161etky d\u00e1ta adresovan\u00e9 ako obe\u017en\u00edky a BUS ich \u0161\u00edri \u010falej pomocou spojen\u00ed typu point-to-multipoint v\u0161etk\u00fdm relevantn\u00fdm pr\u00edjemcom. Okrem toho BUS \u0161\u00edri ako broadcasty tie pakety, ktor\u00e9 s\u00fa s\u00edce ur\u010den\u00e9 jedin\u00e9mu pr\u00edjemcovi, av\u0161ak ktor\u00e9ho MAC adresa e\u0161te nebola prelo\u017een\u00e1 na ATM adresu.<\/p>\n

\u0160tvrt\u00fdm, nepovinn\u00fdm komponentom je<\/p>\n

LECS<\/span><\/p>\n

– LAN Emulation Configuration Server. LECS server uchov\u00e1va inform\u00e1cie o LANE sie\u0165ach a ich parametroch – LES serveroch, ve\u013ekosti r\u00e1mcov, type LANE siete. Ke\u010f sa stanica po \u0161tarte opera\u010dn\u00e9ho syst\u00e9mu prihlasuje do LANE, spravidla vyh\u013ead\u00e1 LECS server na zn\u00e1mej ATM adrese resp. na spojen\u00ed danom pevn\u00fdmi hodnotami VPI\/VCI a vy\u017eiada si od neho inform\u00e1cie pre prihl\u00e1senie do svojej LANE. LECS server m\u00e1 mo\u017enos\u0165 na z\u00e1klade svojich vn\u00fatorn\u00fdch pravidiel rozhodn\u00fa\u0165, do ktorej LANE dan\u00e1 stanica patr\u00ed, a pod\u013ea toho jej ozn\u00e1mi pr\u00edslu\u0161n\u00fd LES server, ve\u013ekos\u0165 r\u00e1mca, meno LANE, jej typ a pr\u00edpadne in\u00e9 podrobnosti. LECS nemus\u00ed v LANE existova\u0165, preto\u017ee v\u0161etky inform\u00e1cie, ktor\u00e9 poskytuje, s\u00fa len konfigura\u010dn\u00e9ho v\u00fdznamu a pre dan\u00fa LANE b\u00fdvaj\u00fa spravidla statick\u00e9. V sie\u0165ach LANE, kde nebe\u017e\u00ed LECS, sa tieto \u00fadaje konfiguruj\u00fa ru\u010dne priamo na \u010dlensk\u00fdch staniciach.<\/p>","protected":false},"excerpt":{"rendered":"

2. Spolupráca ATM a existujúcich sietí a protokolov<\/h2>","protected":false},"author":9,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"footnotes":""},"categories":[178],"tags":[],"class_list":["post-118","post","type-post","status-publish","format-standard","hentry","category-atm-en"],"taxonomy_info":{"category":[{"value":178,"label":"ATM"}]},"featured_image_src_large":false,"author_info":{"display_name":"palo73","author_link":"https:\/\/nil.uniza.sk\/en\/author\/palo73\/"},"comment_info":0,"category_info":[{"term_id":178,"name":"ATM","slug":"atm-en","term_group":0,"term_taxonomy_id":429,"taxonomy":"category","description":"","parent":0,"count":23,"filter":"raw","cat_ID":178,"category_count":23,"category_description":"","cat_name":"ATM","category_nicename":"atm-en","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/nil.uniza.sk\/en\/wp-json\/wp\/v2\/posts\/118","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nil.uniza.sk\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nil.uniza.sk\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nil.uniza.sk\/en\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/nil.uniza.sk\/en\/wp-json\/wp\/v2\/comments?post=118"}],"version-history":[{"count":0,"href":"https:\/\/nil.uniza.sk\/en\/wp-json\/wp\/v2\/posts\/118\/revisions"}],"wp:attachment":[{"href":"https:\/\/nil.uniza.sk\/en\/wp-json\/wp\/v2\/media?parent=118"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nil.uniza.sk\/en\/wp-json\/wp\/v2\/categories?post=118"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nil.uniza.sk\/en\/wp-json\/wp\/v2\/tags?post=118"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}