{"id":33142,"date":"2019-10-31T21:50:58","date_gmt":"2019-10-31T18:50:58","guid":{"rendered":"https:\/\/prohoster.info\/blog\/printsipy-raboty-protokola-pim\/"},"modified":"2019-10-31T21:50:58","modified_gmt":"2019-10-31T18:50:58","slug":"printsipy-raboty-protokola-pim","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sq\/blog\/administrirovanie\/printsipy-raboty-protokola-pim","title":{"rendered":"Parimet e funksionimit t\u00eb protokollit PIM","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Protokolli PIM \u00ebsht\u00eb nj\u00eb grup protokollesh p\u00ebr transmetimin e multicast-it n\u00eb rrjet midis ruter\u00ebve. Marr\u00ebdh\u00ebniet e fqinj\u00ebsis\u00eb nd\u00ebrtohen n\u00eb m\u00ebnyr\u00eb t\u00eb ngjashme si te protokollet dinamike t\u00eb rutimit. PIMv2 d\u00ebrgon mesazhe Hello \u00e7do 30 sekonda n\u00eb adres\u00ebn e rezervuar multicast 224.0.0.13 ( All-PIM-Routers ). Mesazhi p\u00ebrmban Hold Timers \u2014 zakonisht \u00ebsht\u00eb i barabart\u00eb me 3.5*Hello Timer, pra 105 sekonda si parazgjedhje.
\n\"Parimet<\/a><\/noindex>
\n PIM p\u00ebrdor dy m\u00ebnyra kryesore pune \u2014 Dense dhe Sparse mode. Le t\u00eb fillojm\u00eb me Dense mode. <\/a><\/noindex>
\nPem\u00ebt e shp\u00ebrndarjes t\u00eb bazuara te burimi.<\/b>
\nRegjimi Dense-mode \u00ebsht\u00eb i p\u00ebrshtatsh\u00ebm kur ka nj\u00eb num\u00ebr t\u00eb madh klient\u00ebsh t\u00eb grupeve t\u00eb ndryshme multicast. Kur ruteri merr trafik multicast, gj\u00ebja e par\u00eb q\u00eb b\u00ebn \u00ebsht\u00eb ta kontrolloj\u00eb sipas rregullit RPF. RPF \u2014 ky rregull p\u00ebrdoret p\u00ebr t\u00eb verifikuar burimin e multicast-it ndaj tabel\u00ebs s\u00eb rutimit unicast. \u00cbsht\u00eb e nevojshme q\u00eb trafiku t\u00eb vij\u00eb n\u00eb at\u00eb interfejs pas t\u00eb cilit ndodhet ky host sipas tabel\u00ebs s\u00eb rutimit unicast. Ky mekaniz\u00ebm zgjidh problemin e krijimit t\u00eb lakut gjat\u00eb transmetimit t\u00eb multicast-it.
\n \"Parimet<\/a><\/noindex>
\nNga mesazhi multicast, R3 identifikon burimin e multicast-it ( Source IP ) dhe kontrollon dy flukset nga R1 dhe R2 sipas tabel\u00ebs s\u00eb vet t\u00eb rutimit unicast. Fluksi nga ai interfejs t\u00eb cilit i referohet tabela ( R1 te R3 ) do t\u00eb p\u00ebrcillet m\u00eb tej, nd\u00ebrsa fluksi nga R2 do t\u00eb hidhet posht\u00eb, sepse p\u00ebr t\u00eb arritur te burimi i multicast-it, paketat duhet t\u00eb d\u00ebrgohen p\u00ebrmes S0\/1.
\nPo \u00e7far\u00eb ndodh n\u00ebse keni dy rrug\u00eb ekuivalente me t\u00eb nj\u00ebjt\u00ebn metrik\u00eb? N\u00eb k\u00ebt\u00eb rast, ruteri do t\u00eb zgjedh\u00eb sipas next-hop t\u00eb k\u00ebtyre rrug\u00ebve. Fiton ai q\u00eb ka adres\u00ebn IP m\u00eb t\u00eb lart\u00eb. N\u00ebse duhet ndryshuar kjo sjellje, mund t\u00eb p\u00ebrdoret ECMP. M\u00eb shum\u00eb detaje k\u00ebtu<\/a><\/noindex>.
\nPas verifikimit t\u00eb rregullit RPF, ruteri d\u00ebrgon paket\u00ebn multicast te t\u00eb gjith\u00eb fqinj\u00ebt e tij PIM, me p\u00ebrjashtim t\u00eb atij nga i cili u mor kjo paket\u00eb. Ruter\u00ebt e tjer\u00eb PIM e p\u00ebrs\u00ebrisin k\u00ebt\u00eb proces. Rruga q\u00eb ka p\u00ebrshkuar paketa multicast nga burimi deri te marr\u00ebsit p\u00ebrfundimtar\u00eb formon nj\u00eb pem\u00eb q\u00eb quhet \u2014 source-based distribution tree, shortest-path tree (SPT), source tree. Tre em\u00ebrtime t\u00eb ndryshme, zgjidhni cilindo.
\nSi zgjidhet problemi kur disa ruter\u00eb nuk kan\u00eb fare nevoj\u00eb p\u00ebr nj\u00eb fluks t\u00eb caktuar multicast dhe nuk kan\u00eb kujt t\u2019ia d\u00ebrgojn\u00eb, nd\u00ebrsa ruteri n\u00eb nivel m\u00eb t\u00eb lart\u00eb vazhdon t\u2019ua nis\u00eb? P\u00ebr k\u00ebt\u00eb \u00ebsht\u00eb krijuar mekanizmi Prune.
\nMesazhi Prune.<\/b>
\nP\u00ebr shembull, R2 do t\u00eb vazhdoj\u00eb t\u2019i d\u00ebrgoj\u00eb multicast R3, edhe pse R3, sipas rregullit RPF, e hedh posht\u00eb at\u00eb. Pse t\u00eb ngarkohet kanali? R3 d\u00ebrgon nj\u00eb mesazh PIM Prune dhe R2, pasi ta marr\u00eb k\u00ebt\u00eb mesazh, do ta heq\u00eb nd\u00ebrfaqen S0\/1 nga lista ( outgoing interface list ) p\u00ebr k\u00ebt\u00eb rrjedh\u00eb, pra nga lista e nd\u00ebrfaqeve ku duhet t\u00eb d\u00ebrgohet ky trafik. <\/p>\n

M\u00eb posht\u00eb \u00ebsht\u00eb nj\u00eb p\u00ebrkufizim m\u00eb formal i nj\u00eb mesazhi PIM Prune:
\nMesazhi PIM Prune d\u00ebrgohet nga nj\u00eb router te nj\u00eb router i dyt\u00eb p\u00ebr t\u00eb b\u00ebr\u00eb q\u00eb routeri i dyt\u00eb t\u00eb heq\u00eb lidhjen n\u00eb t\u00eb cil\u00ebn \u00ebsht\u00eb marr\u00eb Prune nga nj\u00eb (S,G) SPT i caktuar.<\/p><\/blockquote>\n

\nPas marrjes s\u00eb mesazhit Prune, R2 vendos nj\u00eb koh\u00ebmat\u00ebs Prune prej 3 minutash. Pas tre minutash, ai do t\u00eb nis\u00eb s\u00ebrish t\u00eb d\u00ebrgoj\u00eb trafik, derisa t\u00eb marr\u00eb nj\u00eb tjet\u00ebr mesazh Prune. Kjo vlen p\u00ebr PIMv1.
\nN\u00eb PIMv2 \u00ebsht\u00eb shtuar koh\u00ebmat\u00ebsi State Refresh ( si parazgjedhje 60 sekonda ). Sapo d\u00ebrgohet mesazhi Prune nga R3, ky koh\u00ebmat\u00ebs niset n\u00eb R3. Me p\u00ebrfundimin e k\u00ebtij afati, R3 do t\u00eb d\u00ebrgoj\u00eb nj\u00eb mesazh State Refresh, i cili do t\u00eb rivendos\u00eb koh\u00ebmat\u00ebsin 3-minut\u00ebsh Prune n\u00eb R2 p\u00ebr k\u00ebt\u00eb grup.
\nArsyet p\u00ebr d\u00ebrgimin e nj\u00eb mesazhi Prune:<\/p>\n