{"id":77041,"date":"2020-04-07T13:42:46","date_gmt":"2020-04-07T11:42:46","guid":{"rendered":"https:\/\/prohoster.info\/blog\/administrirovanie\/podrobnosti-realizaczii-protokola-sinhronizaczii-vremeni-ptpv2"},"modified":"2020-04-07T13:42:46","modified_gmt":"2020-04-07T11:42:46","slug":"podrobnosti-realizaczii-protokola-sinhronizaczii-vremeni-ptpv2","status":"publish","type":"post","link":"https:\/\/prohoster.info\/ro\/blog\/administrirovanie\/podrobnosti-realizaczii-protokola-sinhronizaczii-vremeni-ptpv2","title":{"rendered":"Lansarea Firefox 75","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"<p><b>Introducere<\/b><\/p>\n<p>Conceptul de construire a \u00abSubsta\u021biei Digitale\u00bb \u00een energetica electric\u0103 necesit\u0103 sincronizare cu o precizie de 1 \u03bcs. De asemenea, pentru efectuarea tranzac\u021biilor financiare este necesar\u0103 o precizie \u00een \u03bcs. \u00cen aceste aplica\u021bii, precizia timpului NTP este deja insuficient\u0103.<\/p>\n<p>Protocolul de sincronizare PTPv2, descris de standardul IEEE 1588v2, permite ob\u021binerea unei precizii de sincronizare de c\u00e2teva zeci de nanosecunde. PTPv2 permite trimiterea pachetelor de sincronizare prin re\u021bele L2 \u0219i L3.<\/p>\n<p>Principalele domenii \u00een care se aplic\u0103 PTPv2 sunt:<\/p>\n<ul>\n<li>energetic\u0103;<\/li>\n<li>echipamente de m\u0103surare \u0219i control;<\/li>\n<li>complexul industrial \u0219i de ap\u0103rare;<\/li>\n<li>telecomunica\u021bii;<\/li>\n<li>sectorul financiar.<\/li>\n<\/ul>\n<p>\n\u00cen aceast\u0103 postare se analizeaz\u0103 cum func\u021bioneaz\u0103 protocolul de sincronizare PTPv2.<\/p>\n<p>Avem mai mult\u0103 experien\u021b\u0103 \u00een industrie \u0219i \u00eent\u00e2lnim frecvent acest protocol \u00een aplica\u021bii energetice. Prin urmare, vom face o revizuire av\u00e2nd \u00een vedere <noindex><a rel=\"nofollow\" href=\"https:\/\/www.phoenixcontact.com\/online\/portal\/ru?1dmy&amp;urile=wcm%3apath%3a\/ruru\/web\/main\/products\/subcategory_pages\/Managed_switches_P-08-10-16-01\/aead25f7-3319-485d-8868-126c62b77cb1\">sectorul energetic<\/a><\/noindex>.<\/p>\n<p><b>De ce este necesar?<\/b><\/p>\n<p>\u00cen prezent, \u00een STC 34.01-21-004-2019 al PJSC \u201eRosseti\u201d \u0219i \u00een STC 56947007-29.240.10.302-2020 al PJSC \u201eFSK EES\u201d exist\u0103 cerin\u021be pentru organizarea magistralei de proces cu asigurarea sincroniz\u0103rii timpului prin PTPv2.<\/p>\n<p>Acest lucru se datoreaz\u0103 faptului c\u0103 la magistrala de proces sunt conectate terminale de protec\u021bie prin relee \u0219i aparate de m\u0103sur\u0103, care prin magistrala de proces, folosind a\u0219a-numitele fluxuri SV (fluxuri multicast), transmit valori instantanee ale curentului \u0219i tensiunii.<noindex><a rel=\"nofollow\" name=\"habracut\"><\/a><\/noindex><\/p>\n<p>Terminalele de protec\u021bie prin relee folosesc aceste valori pentru implementarea protec\u021biilor conexiunilor. Dac\u0103 precizia m\u0103sur\u0103rilor \u00een timp este mic\u0103, unele protec\u021bii pot reac\u021biona fals.<\/p>\n<p>De exemplu, victimele unei sincroniz\u0103ri temporale \u00abslabe\u00bb pot deveni protec\u021biile cu selec\u021bie absolut\u0103. De obicei, logica unor astfel de protec\u021bii se bazeaz\u0103 pe compararea a dou\u0103 m\u0103rimi. Dac\u0103 m\u0103rimile se abate suficient de mult, protec\u021bia se activeaz\u0103. Dac\u0103 aceste m\u0103rimi au fost m\u0103surate cu o precizie \u00een timp de 1 ms, se poate ob\u021bine o diferen\u021b\u0103 mare acolo unde valoriile se afl\u0103 de fapt \u00een norm\u0103, dac\u0103 sunt m\u0103surate cu o precizie de 1 \u03bcs.<\/p>\n<p><b>Versiunile PTP<\/b><\/p>\n<p>Protocolul PTP a fost descris ini\u021bial \u00een 2002 \u00een standardul IEEE 1588-2002 \u0219i a avut denumirea \u201eStandard pentru un protocol de sincronizare precis\u0103 a ceasului pentru sisteme de m\u0103surare \u0219i control \u00een re\u021bea\u201d. \u00cen 2008 a fost lansat un standard actualizat, IEEE 1588-2008, care descrie PTP Versiunea 2. \u00cen aceast\u0103 versiune a protocolului s-a \u00eembun\u0103t\u0103\u021bit precizia \u0219i stabilitatea, \u00eens\u0103 nu s-a p\u0103strat compatibilitatea \u00eenapoi cu prima versiune. De asemenea, \u00een 2019 a fost lansat\u0103 versiunea standardului IEEE 1588-2019, care descrie PTP v2.1. Aceast\u0103 versiune adaug\u0103 mici \u00eembun\u0103t\u0103\u021biri la PTPv2 \u0219i este compatibil\u0103 \u00eenapoi cu PTPv2.<\/p>\n<p>Cu alte cuvinte, avem urm\u0103toarea situa\u021bie cu versiunile:<\/p>\n<p>PTPv1<br \/>\n(IEEE 1588-2002)<\/p>\n<p>PTPv2<br \/>\n(IEEE 1588-2008)<\/p>\n<p>PTPv2.1<br \/>\n(IEEE 1588-2019)<\/p>\n<p>PTPv1 (IEEE 1588-2002)<\/p>\n<p> \u2014<br \/>\nIncompatibile<\/p>\n<p>Incompatibile<\/p>\n<p>PTPv2 (IEEE 1588-2008)<\/p>\n<p>Incompatibile<\/p>\n<p> \u2014<br \/>\nCompatibile<\/p>\n<p>PTPv2.1 (IEEE 1588-2019)<\/p>\n<p>Incompatibile<\/p>\n<p>Compatibile<\/p>\n<p> \u2014 <\/p>\n<p>\nDar, ca \u00eentotdeauna, exist\u0103 nuan\u021be.<\/p>\n<p>Incompatibilitatea \u00eentre PTPv1 \u0219i PTPv2 presupune c\u0103 un dispozitiv care suport\u0103 PTPv1 nu se poate sincroniza de la ceasuri precise care func\u021bioneaz\u0103 pe PTPv2. Pentru sincronizare, utilizeaz\u0103 formate diferite de mesaje.<\/p>\n<p>Dar este totu\u0219i posibil s\u0103 combin\u0103m dispozitive cu PTPv1 \u0219i dispozitive cu PTPv2 \u00eentr-o singur\u0103 re\u021bea. Pentru aceasta, unii produc\u0103tori permit alegerea versiunii protocolului pe por\u021bile ceasurilor de frontier\u0103. Adic\u0103, ceasurile de frontier\u0103 se pot sincroniza prin PTPv2 \u0219i \u00een acela\u0219i timp pot sincroniza alte ceasuri conectate la ele at\u00e2t prin PTPv1, c\u00e2t \u0219i prin PTPv2.<\/p>\n<p><b>Dispozitive PTP. Ce tipuri exist\u0103 \u0219i cu ce se deosebesc?<\/b><\/p>\n<p>Standardul IEEE 1588v2 descrie mai multe tipuri de dispozitive. Toate acestea sunt prezentate \u00een tabel.<\/p>\n<p>Dispozitivele interac\u021bioneaz\u0103 \u00eentre ele printr-o re\u021bea local\u0103, folosind PTP.<\/p>\n<p>Dispozitivele PTP sunt denumite ceasuri. Toate ceasurile preiau timpul exact de la ceasurile grandmaster.<\/p>\n<p>Exist\u0103 5 tipuri de ceasuri:<\/p>\n<p>Grandmaster clock (Ceasuri grandmaster)<\/p>\n<p>Sursa principal\u0103 de timp exact. Adesea dotat\u0103 cu o interfa\u021b\u0103 pentru conectarea GPS-ului.<\/p>\n<p>Ordinary Clock (Ceasuri obi\u0219nuite)<\/p>\n<p>Dispozitiv cu o singur\u0103 poart\u0103 care poate fi master (ceasuri principale) sau slave (ceasuri secundare)<\/p>\n<p>Ceasuri principale (master)<\/p>\n<p>Sunt sursa de timp exact \u00een jurul c\u0103reia se sincronizeaz\u0103 celelalte ceasuri<\/p>\n<p>Ceasuri secundare (slave)<\/p>\n<p>Dispozitiv final care se sincronizeaz\u0103 de la ceasurile principale<\/p>\n<p>Boundary Clock (Ceasuri de frontier\u0103)<\/p>\n<p>Dispozitiv cu mai multe por\u021bi care poate fi master sau slave.<\/p>\n<p>Adic\u0103 aceste ceasuri se pot sincroniza de la ceasurile principale superioare \u0219i pot sincroniza ceasurile secundare inferioare.<\/p>\n<p>Ceas Transparent End-to-End<\/p>\n<p>Dispozitiv cu mai multe porturi care nu este nici ceas de referin\u021b\u0103, nici ceas secundar. Acesta transmite date PTP \u00eentre dou\u0103 ceasuri. <\/p>\n<p>\u00cen timpul transmiterii datelor, ceasurile transparente corecteaz\u0103 toate mesajele PTP. <\/p>\n<p>Corectarea se face prin ad\u0103ugarea timpului de \u00eent\u00e2rziere pe acest dispozitiv \u00een c\u00e2mpul de corectare din antetul mesajului transmis.<\/p>\n<p>Ceas Transparent Peer-to-Peer<\/p>\n<p>Dispozitiv cu mai multe porturi care nu este nici ceas de referin\u021b\u0103, nici ceas secundar. <br \/>\nAcesta transmite date PTP \u00eentre dou\u0103 ceasuri. <\/p>\n<p>\u00cen timpul transmiterii datelor, ceasurile transparente corecteaz\u0103 toate mesajele PTP Sync \u0219i Follow_Up (despre care se discut\u0103 mai jos).<\/p>\n<p>Corectarea se realizeaz\u0103 prin ad\u0103ugarea \u00eent\u00e2rzierilor din c\u00e2mpul de corectare al pachetului transmis \u0219i din canalul de transmisie a datelor.<\/p>\n<p>Nod de Management<\/p>\n<p>Dispozitiv care configureaz\u0103 \u0219i diagnosticheaz\u0103 alte ceasuri.<\/p>\n<p>Ceasurile de referin\u021b\u0103 \u0219i secundare sunt sincronizate folosind marcaje temporale \u00een mesajele PTP. Exist\u0103 dou\u0103 tipuri de mesaje \u00een protocolul PTP:<\/p>\n<ul>\n<li>Mesaje de Eveniment \u2013 acestea sunt mesaje sincronizate care presupun generarea marcajului temporal \u00een momentul trimiterii \u0219i \u00een momentul primirii mesajului.<\/li>\n<li>Mesaje Generale \u2013 aceste mesaje nu necesit\u0103 marcaje temporale, dar pot con\u021bine marcaje temporale pentru mesaje corelate.<\/li>\n<\/ul>\n<p><\/p>\n<p>Mesaje de Eveniment<\/p>\n<p>Mesaje Generale<\/p>\n<p>Sync<br \/>\nDelay_Req<br \/>\nPdelay_Req<br \/>\nPdelay_Resp<\/p>\n<p>Anun\u021bare<br \/>\nFollow_Up<br \/>\nDelay_Resp<br \/>\nPdelay_Resp_Follow_Up<br \/>\nManagement<br \/>\nSignaling<\/p>\n<p>\u00cen continuare, toate tipurile de mesaje vor fi discutate \u00een detaliu.<\/p>\n<p><b>Problemele principale de sincronizare<\/b><\/p>\n<p>Atunci c\u00e2nd un pachet de sincronizare este transmis printr-o re\u021bea local\u0103, acesta este \u00eent\u00e2rziat de comutator \u0219i de canalul de transmisie. Orice comutator va oferi o \u00eent\u00e2rziere de aproximativ 10 \u03bcs, ceea ce este inacceptabil pentru PTPv2. Este necesar ca la dispozitivul de destina\u021bie s\u0103 ob\u021binem o precizie de 1 \u03bcs. (Aceasta dac\u0103 se refer\u0103 la energie. Alte aplica\u021bii pot necesita o precizie chiar mai mare.)<\/p>\n<p>\u00cen IEEE 1588v2 sunt descrise mai multe algoritmi de lucru care permit m\u0103surarea \u00eent\u00e2rzierii \u00een timp \u0219i corectarea acesteia.<\/p>\n<p><b>Algoritmul de func\u021bionare<\/b><br \/>\n\u00cen condi\u021bii normale de func\u021bionare, protocolul func\u021bioneaz\u0103 \u00een dou\u0103 faze.<\/p>\n<ul>\n<li>Faza 1 \u2013 stabilirea ierarhiei \"Ceasuri de referin\u021b\u0103 \u2013 Ceasuri secundare\".<\/li>\n<li>Faza 2 \u2013 sincronizarea ceasurilor prin mecanismul End-to-End sau Peer-to-Peer.<\/li>\n<\/ul>\n<p>\n<i>Faza 1 \u2014 Instalarea ierarhiei \u201eMaster-Slave\u201d<\/i><\/p>\n<p>Fiecare port al ceasurilor obi\u0219nuite sau de frontier\u0103 are un num\u0103r specific de st\u0103ri (ceasuri secundare \u0219i ceasuri principale). Standardul descrie algoritmul de tranzi\u021bie \u00eentre aceste st\u0103ri. \u00cen programare, un astfel de algoritm este numit automat\u0103 finit\u0103 sau ma\u0219in\u0103 de st\u0103ri (mai multe detalii \u00een Wiki).<\/p>\n<p>Aceast\u0103 automat\u0103 finit\u0103 utilizeaz\u0103 algoritmul Best Master Clock Algorithm (BMCA) pentru a stabili masterul atunci c\u00e2nd se conecteaz\u0103 dou\u0103 ceasuri.<\/p>\n<p>Acest algoritm permite ceasurilor s\u0103 \u00ee\u0219i asume responsabilit\u0103\u021bile ceasurilor de mare m\u0103estrie, atunci c\u00e2nd ceasurile de mare m\u0103estrie superioare pierd semnalul GPS, se deconecteaz\u0103 de la re\u021bea etc.<\/p>\n<p>Tranzi\u021biile \u00eentre st\u0103ri conform BMCA sunt prezentate sumar \u00een urm\u0103torul grafic:<br \/>\n<img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/add811d60135de3be9c6865a5e4493c1.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nInforma\u021biile despre ceasuri de la cel\u0103lalt cap\u0103t al \u201ecablului\u201d sunt trimise \u00eentr-un mesaj special (mesaj de anun\u021bare). Odat\u0103 ce aceste informa\u021bii sunt primite, algoritmul ma\u0219inii de st\u0103ri este activat \u0219i se compar\u0103 care ceas este mai bun. Portul ceasurilor superioare devine ceas principal.<\/p>\n<p>Ierarhia simpl\u0103 este reprezentat\u0103 \u00een schema de mai jos. C\u0103r\u021bile 1, 2, 3, 4, 5 pot con\u021bine ceasuri transparente (Transparent clock), dar nu particip\u0103 la stabilirea ierarhiei \u201eCeasuri principale \u2013 Ceasuri secundare\u201d.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/05831c032a2d4df286ef41c531c949a3.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Faza 2 \u2014 Sincronizarea ceasurilor obi\u0219nuite \u0219i a ceasurilor de frontier\u0103<\/b><\/p>\n<p>Imediat dup\u0103 stabilirea ierarhiei \u201eCeasuri principale \u2013 Ceasuri secundare\u201d \u00eencepe faza de sincronizare a ceasurilor obi\u0219nuite \u0219i a ceasurilor de frontier\u0103.<\/p>\n<p>Pentru sincronizare, ceasurile principale trimit ceasurilor secundare un mesaj care con\u021bine un timestamp.<\/p>\n<p>Ceasurile principale pot fi:<\/p>\n<ul>\n<li>unice;<\/li>\n<li>dual.<\/li>\n<\/ul>\n<p>\nCeasurile unice pentru sincronizare trimit un singur mesaj Sync.<\/p>\n<p>Ceasurile duale pentru sincronizare utilizeaz\u0103 dou\u0103 mesaje \u2013 Sync \u0219i Follow_Up.<\/p>\n<p>Pentru faza de sincronizare pot fi utilizate dou\u0103 mecanisme:<\/p>\n<ul>\n<li>Mecanismul de cerere-r\u0103spuns pentru \u00eent\u00e2rziere (Delay request-response mechanism).<\/li>\n<li>Mecanismul de m\u0103surare a \u00eent\u00e2rzierei nodului vecin (Peer delay measurement mechanism).<\/li>\n<\/ul>\n<p>\nLa \u00eenceput, s\u0103 analiz\u0103m aceste mecanisme \u00een cel mai simplu caz \u2013 atunci c\u00e2nd nu se utilizeaz\u0103 ceasuri transparente.<\/p>\n<p>Mecanismul de cerere-r\u0103spuns pentru \u00eent\u00e2rziere (Delay request-response mechanism)<\/p>\n<p>Mecanismul presupune dou\u0103 etape:<\/p>\n<ol>\n<li>M\u0103surarea \u00eent\u00e2rzierii \u00een transmiterea mesajului \u00eentre ceasurile principale \u0219i cele secundare. Aceasta se face prin mecanismul de cerere-r\u0103spuns pentru \u00eent\u00e2rziere.<\/li>\n<li>Se efectueaz\u0103 corectarea diferen\u021bei de timp precis.<\/li>\n<\/ol>\n<p>\n<i>M\u0103surarea \u00eent\u00e2rzierii<\/i><br \/>\n<img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/3a0d534384329c6232259736995eb0bd.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nt1 \u2013 Timpul de trimitere a mesajului Sync de c\u0103tre ceasurile principale; t2 \u2013 Timpul de primire a mesajului Sync de c\u0103tre ceasurile secundare; t3 \u2013 Timpul de trimitere a cererii de \u00eent\u00e2rziere (Delay_Req) de c\u0103tre ceasurile secundare; t4 \u2013 Timpul de primire a Delay_Req de c\u0103tre ceasurile principale.<\/p>\n<p>C\u00e2nd ceasurile secundare cunosc timpul t1, t2, t3 \u0219i t4, ele pot calcula \u00eent\u00e2rzierea medie la transmiterea mesajului de sincronizare (tmpd). Aceasta se calculeaz\u0103 dup\u0103 cum urmeaz\u0103:<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/513eb7352a143073835fe36aedd9cb98.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nLa transmiterea mesajului Sync \u0219i a Follow_Up se calculeaz\u0103 \u00eent\u00e2rzierea de timp de la master la slave \u2013 t-ms.<\/p>\n<p>La transmiterea mesajelor Delay_Req \u0219i Delay_Resp se calculeaz\u0103 \u00eent\u00e2rzierea de timp de la slave la master \u2013 t-sm.<\/p>\n<p>Dac\u0103 \u00eentre aceste dou\u0103 valori apare o asimetie, atunci apare o eroare de corec\u021bie a timpului exact. Eroarea este determinat\u0103 de faptul c\u0103 \u00eent\u00e2rzierea calculat\u0103 este media \u00eent\u00e2rziatelor t-ms \u0219i t-sm. Dac\u0103 \u00eent\u00e2rzierea nu sunt egale \u00eentre ele, atunci vom corecta timpul imprecis.<\/p>\n<p><i>Corec\u021bia deplas\u0103rii timpului exact<\/i><\/p>\n<p>Dup\u0103 ce \u00eent\u00e2rzierea dintre ceasurile principale \u0219i cele secundare este cunoscut\u0103, ceasurile secundare efectueaz\u0103 corec\u021bia timpului.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/27f230252126a768273b40e8c8e7cc4e.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nCeasurile secundare utilizeaz\u0103 mesajul Sync \u0219i mesajul op\u021bional Follow_Up pentru a calcula deplasarea timpului exact la transmiterea pachetului de la ceasurile principale la cele secundare. Deplasarea este calculat\u0103 conform urm\u0103toarei formule:<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/190604a9287f285e191eb26381fca52c.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Mecanismul pentru m\u0103surarea \u00eent\u00e2rzierei nodului vecin (Peer delay measurement mechanism)<\/b><\/p>\n<p>Acest mecanism utilizeaz\u0103 de asemenea dou\u0103 etape pentru sincronizare:<\/p>\n<ol>\n<li>Dispozitivele m\u0103soar\u0103 \u00eent\u00e2rzierea timpului c\u0103tre to\u021bi vecinii prin toate porturile. Pentru aceasta, ele utilizeaz\u0103 mecanismul de \u00eent\u00e2rziere peer.<\/li>\n<li>Corec\u021bia deplas\u0103rii timpului exact.<\/li>\n<\/ol>\n<p>\n<i>M\u0103surarea \u00eent\u00e2rzierei \u00eentre dispozitive care suport\u0103 modul Peer-to-Peer<\/i><\/p>\n<p>\u00cent\u00e2rzierea \u00eentre porturile care suport\u0103 mecanismul peer-to-peer este m\u0103surat\u0103 folosind urm\u0103toarele mesaje:<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/897c9914110e9a56f98f4fa835f524cd.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nC\u00e2nd portul 1 cunoa\u0219te timpul t1, t2, t3 \u0219i t4, el poate calcula \u00eent\u00e2rzierea medie (tmld). Aceasta se calculeaz\u0103 conform urm\u0103toarei formule:<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/17416bf3b60f86136002b27cf4987b27.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nApoi, portul utilizeaz\u0103 aceast\u0103 valoare la calcularea c\u00e2mpului de corec\u021bie pentru fiecare mesaj Sync sau mesajul op\u021bional Follow_Up care trece prin acest dispozitiv. <\/p>\n<p>\u00cent\u00e2rzierea final\u0103 va fi egal\u0103 cu suma \u00eent\u00e2rzierei la transmiterea prin acest dispozitiv, \u00eent\u00e2rzierea medie la transmiterea prin canalul de date \u0219i \u00eent\u00e2rzierea deja con\u021binut\u0103 \u00een acest mesaj, inclus\u0103 pe dispozitivele superioare.<\/p>\n<p>Mesajele Pdelay_Req, Pdelay_Resp \u0219i op\u021bional Pdelay_Resp_Follow_Up permit ob\u021binerea \u00eent\u00e2rzierii de la maestru la slaiv \u0219i de la slaiv la maestru (circular\u0103).<\/p>\n<p>Orice asimetrie \u00eentre aceste dou\u0103 valori va introduce o eroare de corectare a decalajului de timp precis.<\/p>\n<p><i>Corectarea decalajului de timp precis<\/i><\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/c9cdedffd98db044718b8bc0eef156b9.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nCeasurile slave utilizeaz\u0103 mesajul Sync \u0219i mesajul op\u021bional Follow_Up pentru a calcula decalajul de timp precis la transferul pachetului de la ceasurile principale la cele slave. Decalajul este calculat conform urm\u0103toarei formule:<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/dff497d0f5644c3591f05f99e4c8c23a.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nAvantajele corect\u0103rii mecanismului peer-to-peer \u2013 decalajul fiec\u0103rui mesaj Sync sau Follow_Up este calculat pe parcursul transmiterii \u00een re\u021bea. Prin urmare, modificarea traseului de transmitere nu va afecta deloc acurate\u021bea corect\u0103rii.<\/p>\n<p>C\u00e2nd se folose\u0219te acest mecanism, sincronizarea timpului nu necesit\u0103 calcularea decalajului de timp pe traseul parcurs de pachetul de sincronizare, a\u0219a cum se face \u00een schimbul de baz\u0103. Asta \u00eenseamn\u0103 c\u0103 mesajele Delay_Req \u0219i Delay_Resp nu sunt trimise. \u00cen aceast\u0103 metod\u0103, decalajul dintre ceasurile principale \u0219i cele slave este pur \u0219i simplu sumat \u00een c\u00e2mpul de corectare al fiec\u0103rui mesaj Sync sau Follow_Up.<\/p>\n<p>Un alt avantaj \u2013 ceasurile principale sunt desc\u0103rcate de obliga\u021bia de a procesa mesajele Delay_Req.<\/p>\n<p><b>Modurile de operare ale ceasurilor transparente<\/b><\/p>\n<p>\u00cen consecin\u021b\u0103, acestea au fost exemple simple. Acum s\u0103 presupunem c\u0103 pe calea de sincronizare apar comutatoare.<\/p>\n<p>Dac\u0103 se folosesc comutatoare f\u0103r\u0103 suport pentru PTPv2, atunci pachetul de sincronizare va fi \u00eent\u00e2rziat pe comutator cu aproximativ 10 \u03bcs.<\/p>\n<p>Comutatoarele cu suport pentru PTPv2, conform terminologiei IEEE 1588v2, sunt numite ceasuri transparente (Transparent clock). Ceasurile transparente nu se sincronizeaz\u0103 de la ceasurile principale \u0219i nu particip\u0103 \u00een ierarhia \u201eCeasuri principale \u2013 Ceasuri slave\u201d, dar la transmiterea mesajelor de sincronizare, acestea re\u021bin c\u00e2t de mult mesajul a fost \u00eent\u00e2rziat pe ele. Acest lucru permite corectarea decalajului de timp.<\/p>\n<p>Ceasurile transparente pot func\u021biona \u00een dou\u0103 moduri:<\/p>\n<ul>\n<li>End-to-End.<\/li>\n<li>Peer-to-Peer.<\/li>\n<\/ul>\n<p>\n<b>End-to-End (E2E)<\/b><\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/94e5d2f343d1657f1458adcbb344d024.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nCeasurile transparente E2E transmit mesajele Sync \u0219i mesajele asociate Follow_Up pe toate porturile. Chiar \u0219i pe cele care sunt blocate de anumite protocoale (de exemplu, RSTP).<\/p>\n<p>Comutatorul aminte\u0219te marca de timp c\u00e2nd pachetul Sync (Follow_Up) a fost primit la port \u0219i c\u00e2nd a fost trimis de la port. Pe baza acestor dou\u0103 m\u0103rci de timp, se calculeaz\u0103 timpul de procesare al mesajului de c\u0103tre comutator. \u00cen standard, acest timp se nume\u0219te timpul de reziden\u021b\u0103.<\/p>\n<p>Timpul de procesare este ad\u0103ugat \u00een c\u00e2mpul correctionField al mesajului Sync (ceasuri unistep) sau Follow_Up (ceasuri dualstep).<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/b04cfa6cd1a93f25222079d5bb864a6d.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nCeasurile transparente E2E m\u0103soar\u0103 timpul de procesare pentru mesajele Sync \u0219i Delay_Req care trec prin comutator. Dar este important s\u0103 \u00een\u021belegi c\u0103 \u00eent\u00e2rzierea de timp \u00eentre ceasurile ma\u00eetre \u0219i cele slave este calculat\u0103 folosind mecanismul de solicitare-r\u0103spuns al \u00eent\u00e2rzierii. Dac\u0103 ceasurile ma\u00eetre se schimb\u0103 sau calea de la ceasurile ma\u00eetre la cele slave se schimb\u0103, atunci \u00eent\u00e2rzierea este m\u0103surat\u0103 din nou. Acest lucru m\u0103re\u0219te timpul de tranzi\u021bie \u00een cazul unor modific\u0103ri \u00een re\u021bea.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/5bcb72a639accf802ffba7a1fa9a4767.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nCeasurile transparente P2P, pe l\u00e2ng\u0103 m\u0103surarea timpului de procesare al mesajului de c\u0103tre comutator, m\u0103soar\u0103 \u00eent\u00e2rzierea pe canalul de transfer de date p\u00e2n\u0103 la cel mai apropiat vecin, utiliz\u00e2nd mecanismul de m\u0103surare a \u00eent\u00e2rzierii nodului vecin.<\/p>\n<p>\u00cent\u00e2rzierile sunt m\u0103surate pe fiecare canal \u00een ambele direc\u021bii, inclusiv pe canalele care sunt blocate de un anumit protocol (de exemplu, RSTP). Acest lucru permite calcularea imediat\u0103 a unei noi \u00eent\u00e2rzieri pe calea de sincronizare, dac\u0103 ceasurile gromaster se schimb\u0103 sau dac\u0103 topologia re\u021belei se schimb\u0103.<\/p>\n<p>Timpul de procesare al mesajelor de c\u0103tre comutatoare \u0219i timpul de \u00eent\u00e2rziere se acumuleaz\u0103 \u00een timpul transmiterii mesajelor Sync sau Follow_Up.<\/p>\n<p><b>Tipuri de suport PTPv2 de c\u0103tre comutatoare<\/b><\/p>\n<p>Comutatoarele pot suporta PTPv2:<\/p>\n<ul>\n<li>software;<\/li>\n<li>hardware.<\/li>\n<\/ul>\n<p>\n\u00cen cazul unei implement\u0103ri software a protocoalelor PTPv2, comutatorul solicit\u0103 marca de timp de la firmware. Problema este c\u0103 firmware-ul func\u021bioneaz\u0103 ciclic \u0219i va trebui s\u0103 a\u0219tepte p\u00e2n\u0103 c\u00e2nd finalizeaz\u0103 ciclul curent, va prelua solicitarea \u0219i, dup\u0103 finalizarea ciclului urm\u0103tor, va emite marca de timp. Tot acest proces va lua timp, iar noi vom ob\u021bine o \u00eent\u00e2rziere, de\u0219i nu at\u00e2t de semnificativ\u0103 cum va fi f\u0103r\u0103 suport software pentru PTPv2.<\/p>\n<p>Respectarea preciziei necesare este posibil\u0103 doar cu suport hardware PTPv2. \u00cen acest caz, emiterea m\u0103rcii de timp este realizat\u0103 de un ASIC special instalat la port.<\/p>\n<p><b>Formatul mesajului<\/b><\/p>\n<p>Toate mesajele PTP constau din urm\u0103toarele c\u00e2mpuri:<\/p>\n<ul>\n<li>Header \u2013 34 de bi\u021bi.<\/li>\n<li>Body \u2013 dimensiunea variaz\u0103 \u00een func\u021bie de tipul mesajului.<\/li>\n<li>Suffix \u2013 op\u021bional.<\/li>\n<\/ul>\n<p>\n<img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/99086e6601dcdf8f41c10f273c4ebfdc.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Header<\/b><\/p>\n<p>C\u00e2mpul Header este identic pentru toate mesajele PTP. Dimensiunea sa este de 34 de octe\u021bi.<\/p>\n<p>Formatul c\u00e2mpului Header:<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/e4500d7e9026d9d059b1dcd668a44e5f.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>messageType <\/b>\u2013 con\u021bine tipul mesajului transmis, de exemplu, Sync, Delay_Req, PDelay_Req etc.<\/p>\n<p><b>messageLength<\/b> \u2013 con\u021bine dimensiunea total\u0103 a mesajului PTP, inclusiv header, body \u0219i suffix (dar exclude octe\u021bii de umplere).<\/p>\n<p><b>domainNumber<\/b> \u2013 define\u0219te la ce <a class=\"wpil_keyword_link\" href=\"https:\/\/prohoster.info\/ro\/domain\/\"   title=\"domeniu\" data-wpil-keyword-link=\"linked\"  data-wpil-monitor-id=\"1225\">domeniu<\/a> PTP apar\u021bine mesajul.<\/p>\n<p><b>Domeniu<\/b> \u2013 acesta este un grup de ceasuri diferite, adunate \u00eentr-un singur grup logic \u0219i sincronizate dintr-o surs\u0103 principal\u0103, dar nu neap\u0103rat sincronizate cu ceasuri care apar\u021bin altui domeniu.<\/p>\n<p><b>flags<\/b> \u2013 acest c\u00e2mp con\u021bine diverse flaguri pentru identificarea st\u0103rii mesajului.<\/p>\n<p><b>correctionField<\/b> \u2013 con\u021bine timpul de \u00eent\u00e2rziere \u00een nanosecunde. Timpul de \u00eent\u00e2rziere include \u00eent\u00e2rzierile de transmisie prin ceasuri transparente, precum \u0219i \u00eent\u00e2rzierile de transmisie prin canal \u00een modul Peer-to-Peer.<\/p>\n<p><b>sourcePortIdentity<\/b> \u2013 acest c\u00e2mp con\u021bine informa\u021bii despre portul de la care a fost ini\u021bial trimis acest mesaj.<\/p>\n<p><b>sequenceID<\/b> \u2013 con\u021bine un num\u0103r de identificare pentru mesaje individuale.<\/p>\n<p><b>controlField<\/b> \u2013 c\u00e2mp artefact=) A r\u0103mas din prima versiune a standardului \u0219i con\u021bine informa\u021bii despre tipul acestui mesaj. Practic, este acela\u0219i lucru cu messageType, dar cu mai pu\u021bine op\u021biuni.<\/p>\n<p><b>logMessageInterval<\/b> \u2013 acest c\u00e2mp este definit de tipul mesajului.<\/p>\n<p><b>Corpul<\/b><\/p>\n<p>Dup\u0103 cum a fost discutat mai sus, exist\u0103 mai multe tipuri de mesaje. Aceste tipuri sunt descrise mai jos:<\/p>\n<p><b>Mesajul Announce<\/b><br \/>\nMesajul Announce este folosit pentru a \u201eanun\u021ba\u201d alte ceasuri dintr-un domeniu despre parametrii s\u0103i. Acest mesaj permite stabilirea unei ierarhii \u201eCeasuri principale \u2013 Ceasuri secundare\u201d.<br \/>\n<img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/054b35f0c74757d531205fa352b90f4e.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Mesajul Sync<\/b><br \/>\nMesajul de sincronizare (Sync) este trimis de ceasurile principale \u0219i con\u021bine timpul ceasului principal la momentul \u00een care mesajul Sync a fost creat. Dac\u0103 ceasurile principale sunt cu dou\u0103 etape, atunci timestamp-ul din mesajul Sync va fi egal cu 0, iar timestamp-ul actual va fi trimis \u00een mesajul asociat Follow_Up. Mesajul Sync este utilizat pentru ambele mecanisme de m\u0103surare a \u00eent\u00e2rzierii.<\/p>\n<p>Mesajul este transmis prin Multicast. Op\u021bional, se poate utiliza Unicast.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/38268221aa5663ba021f225c9de01df9.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Mesajul Delay_Req<\/b><\/p>\n<p>Formatul mesajului Delay_Req este identic cu cel al mesajului Sync. Ceasurile secundare trimit Delay_Req. Acesta con\u021bine timpul de trimitere a Delay_Req de c\u0103tre ceasurile secundare. Acest mesaj este utilizat doar pentru mecanismul de solicitare-r\u0103spuns al \u00eent\u00e2rzierii.<\/p>\n<p>Mesajul este transmis prin Multicast. Op\u021bional, se poate utiliza Unicast.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/1e64f3902ff3364b968581ff6b6a6573.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Mesaj Follow_Up<\/b><\/p>\n<p>Mesajul Follow_Up este trimis op\u021bional de c\u0103tre ceasurile master \u0219i con\u021bine timpul de trimitere. <b>mesaje Sync<\/b> mesajul master. Mesajul Follow_Up este trimis doar de ceasurile master cu dou\u0103 etape.<\/p>\n<p>Mesajul Follow_Up este utilizat pentru ambele mecanisme de m\u0103surare a \u00eent\u00e2rzierii.<\/p>\n<p>Mesajul este transmis prin Multicast. Op\u021bional, se poate utiliza Unicast.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/00917743466b8a331922d18e0928d3db.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Mesaj Delay_Resp<\/b><\/p>\n<p>Mesajul Delay_Resp este trimis de ceasurile master. Acesta con\u021bine timpul de primire a Delay_Req de c\u0103tre ceasurile master. Acest mesaj este utilizat doar pentru mecanismul de solicitare-r\u0103spuns al \u00eent\u00e2rzierii.<\/p>\n<p>Mesajul este transmis prin Multicast. Op\u021bional, se poate utiliza Unicast.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/b9d0bc41f94ceee560c0c593dd9e4afd.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Mesaj Pdelay_Req<\/b><\/p>\n<p>Mesajul Pdelay_Req este trimis de dispozitivul care solicit\u0103 \u00eent\u00e2rzirea. Acesta con\u021bine timpul de trimitere a mesajului de pe portul acestui dispozitiv. Pdelay_Req este utilizat doar pentru mecanismul de m\u0103surare a \u00eent\u00e2rzierii nodului vecin.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/7eef44a2655158758cdbcfbc25fc2e48.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Mesaj Pdelay_Resp<\/b><\/p>\n<p>Mesajul Pdelay_Resp este trimis de dispozitivul care a primit solicitarea de \u00eent\u00e2rzire. Acesta con\u021bine timpul de primire a mesajului Pdelay_Req de c\u0103tre acest dispozitiv. Mesajele Pdelay_Resp sunt utilizate doar pentru mecanismul de m\u0103surare a \u00eent\u00e2rzierii nodului vecin.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/6a3bb44c70fc09db3025df93c4d58a3f.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Mesaj Pdelay_Resp_Follow_Up<\/b><\/p>\n<p>Mesajul Pdelay_Resp_Follow_Up este trimis op\u021bional de c\u0103tre dispozitivul care a primit solicitarea de \u00eent\u00e2rzire. Acesta con\u021bine timpul de primire a mesajului Pdelay_Req de c\u0103tre acest dispozitiv. Mesajul Pdelay_Resp_Follow_Up este trimis doar de ceasurile master cu dou\u0103 etape.<\/p>\n<p>De asemenea, acest mesaj poate fi utilizat pentru timpul de execu\u021bie \u00een loc de marca temporal\u0103. Timpul de execu\u021bie este timpul de la momentul primirii Pdelay-Req p\u00e2n\u0103 la trimiterea Pdelay_Resp.<\/p>\n<p>Pdelay_Resp_Follow_Up sunt utilizate doar pentru mecanismul de m\u0103surare a \u00eent\u00e2rzierii nodului vecin.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/523043f7a880030474098fcdc1c5822d.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Mesaje de gestionare (Mesaj Management)<\/b><\/p>\n<p>Mesajele de gestionare PTP sunt necesare pentru transmiterea informa\u021biilor \u00eentre unul sau mai multe ceasuri \u0219i nodul de gestionare.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/4388d9f4b6b12f3a2cdc764c20597499.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Transmitere \u00een LV<\/b><\/p>\n<p>Mesajul PTP poate fi transmis la dou\u0103 niveluri:<\/p>\n<ul>\n<li>Nivelul de re\u021bea \u2013 ca parte a datelor IP.<\/li>\n<li>Nivelul de leg\u0103tur\u0103 \u2013 ca parte a cadrelor Ethernet.<\/li>\n<\/ul>\n<p>\nTransmiterea mesajului PTP prin UDP prin IP prin Ethernet<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/361e008fc48396915e5e9c23cc52bd63.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nPTP prin UDP prin Ethernet<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/1862a5d27931a744e75e3c5bc63d7091.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n<b>Profile<\/b><\/p>\n<p>PTP are o serie de parametri \"flexibili\" care trebuie configura\u021bi. De exemplu:<\/p>\n<ul>\n<li>Op\u021biuni BMCA.<\/li>\n<li>Mecanismul de m\u0103surare a \u00eent\u00e2rzierii.<\/li>\n<li>Intervale \u0219i valori ini\u021biale pentru to\u021bi parametrii configurabili etc.<\/li>\n<\/ul>\n<p>\n\u0218i, \u00een ciuda faptului c\u0103 anterior am spus c\u0103 dispozitivele PTPv2 sunt compatibile \u00eentre ele, \u00een realitate, nu este a\u0219a. Dispozitivele trebuie s\u0103 aib\u0103 set\u0103ri identice pentru a interac\u021biona.<\/p>\n<p>A\u0219adar, exist\u0103 a\u0219a-numitele profiluri PTPv2. Profilurile sunt grupuri configurate de set\u0103ri \u0219i restric\u021bii specifice ale protocolului, astfel \u00eenc\u00e2t s\u0103 se poat\u0103 realiza sincronizarea timpului pentru o aplica\u021bie specific\u0103.<\/p>\n<p>Standardul IEEE 1588v2 descrie un singur profil \u2013 \u201eProfilul Implicit\u201d. Toate celelalte profiluri sunt create \u0219i descrise de diverse organiza\u021bii \u0219i asocia\u021bii.<\/p>\n<p>De exemplu, profilul pentru energia electric\u0103 sau Profilul PTPv2 Power a fost creat de Comitetul de Rela\u021bii cu Sistemele de Energie \u0219i de Comitetul de Substa\u021bie din cadrul IEEE Power and Energy Society. Profilul poart\u0103 numele IEEE C37.238-2011.<\/p>\n<p>Profilul descrie c\u0103 PTP poate fi transmis:<\/p>\n<ul>\n<li>Numai prin re\u021bele L2 (adic\u0103 Ethernet, HSR, PRP, nu IP).<\/li>\n<li>Mesajele sunt transmise doar prin multicast.<\/li>\n<li>Ca mecanism de m\u0103surare a \u00eent\u00e2rzierii se utilizeaz\u0103 mecanismul de m\u0103surare a \u00eent\u00e2rzierii Peer.<\/li>\n<\/ul>\n<p>\nDomeniul implicit \u2013 0, domeniul recomandat \u2013 93.<\/p>\n<p>\u00cen filosofia cre\u0103rii C37.238-2011 a fost dorin\u021ba de a reduce num\u0103rul caracteristicilor op\u021bionale \u0219i de a p\u0103stra doar func\u021biile necesare pentru o interac\u021biune fiabil\u0103 \u00eentre dispozitive \u0219i cre\u0219terea stabilit\u0103\u021bii sistemului.<\/p>\n<p>De asemenea, a fost definit\u0103 frecven\u021ba de transmitere a mesajelor:<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/117c81192ff2eb160652738bb9ecbb1d.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\n\u00cen esen\u021b\u0103, pentru alegere este disponibil un singur parametru \u2013 tipul ceasurilor principale (un singur nivel sau dou\u0103 niveluri).<\/p>\n<p>Precizia trebuie s\u0103 fie de maximum 1 \u03bcs. Cu alte cuvinte, \u00eentr-o cale de sincronizare pot fi incluse maximal 15 ceasuri transparente sau 3 ceasuri de limit\u0103.<\/p>\n<p><img decoding=\"async\" alt=\"Lansarea Firefox 75\" src=\"\/wp-content\/uploads\/2020\/04\/d3f1cb822d01b8733eadb6cd75805b20.jpg\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>Sursa: <a content=\"nofollow\" rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/company\/phoenix_contact\/blog\/495920\/\">habr.com<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"<p>\u0412\u0432\u0435\u0434\u0435\u043d\u0438\u0435 \u041a\u043e\u043d\u0446\u0435\u043f\u0446\u0438\u044f \u043f\u043e\u0441\u0442\u0440\u043e\u0435\u043d\u0438\u044f \u00ab\u0426\u0438\u0444\u0440\u043e\u0432\u043e\u0439 \u043f\u043e\u0434\u0441\u0442\u0430\u043d\u0446\u0438\u0438\u00bb \u0432 \u044d\u043b\u0435\u043a\u0442\u0440\u043e\u044d\u043d\u0435\u0440\u0433\u0435\u0442\u0438\u043a\u0435 \u0442\u0440\u0435\u0431\u0443\u0435\u0442 \u0441\u0438\u043d\u0445\u0440\u043e\u043d\u0438\u0437\u0430\u0446\u0438\u0438 \u0441 \u0442\u043e\u0447\u043d\u043e\u0441\u0442\u044c\u044e 1 \u043c\u043a\u0441. \u0414\u043b\u044f \u043f\u0440\u043e\u0432\u0435\u0434\u0435\u043d\u0438\u044f \u0444\u0438\u043d\u0430\u043d\u0441\u043e\u0432\u044b\u0445 \u0442\u0440\u0430\u043d\u0437\u0430\u043a\u0446\u0438\u0439 \u0442\u0430\u043a\u0436\u0435 \u0442\u0440\u0435\u0431\u0443\u0435\u0442\u0441\u044f \u0442\u043e\u0447\u043d\u043e\u0441\u0442\u044c \u0432 \u043c\u043a\u0441. \u0412 \u044d\u0442\u0438\u0445 \u043f\u0440\u0438\u043b\u043e\u0436\u0435\u043d\u0438\u044f\u0445 \u0442\u043e\u0447\u043d\u043e\u0441\u0442\u0438 \u0432\u0440\u0435\u043c\u0435\u043d\u0438 NTP \u0443\u0436\u0435 \u043d\u0435\u0434\u043e\u0441\u0442\u0430\u0442\u043e\u0447\u043d\u043e. \u041f\u0440\u043e\u0442\u043e\u043a\u043e\u043b \u0441\u0438\u043d\u0445\u0440\u043e\u043d\u0438\u0437\u0430\u0446\u0438\u0438 PTPv2, \u043e\u043f\u0438\u0441\u0430\u043d\u043d\u044b\u0439 \u0441\u0442\u0430\u043d\u0434\u0430\u0440\u0442\u043e\u043c IEEE 1588v2, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \u0434\u043e\u0431\u0438\u0442\u044c\u0441\u044f \u0442\u043e\u0447\u043d\u043e\u0441\u0442\u0438 \u0441\u0438\u043d\u0445\u0440\u043e\u043d\u0438\u0437\u0430\u0446\u0438\u0438 \u0432 \u043d\u0435\u0441\u043a\u043e\u043b\u044c\u043a\u043e \u0434\u0435\u0441\u044f\u0442\u043a\u043e\u0432 \u043d\u0430\u043d\u043e\u0441\u0435\u043a\u0443\u043d\u0434. PTPv2 \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \u043e\u0442\u043f\u0440\u0430\u0432\u043b\u044f\u0442\u044c \u043f\u0430\u043a\u0435\u0442\u044b \u0441\u0438\u043d\u0445\u0440\u043e\u043d\u0438\u0437\u0430\u0446\u0438\u0438 \u0447\u0435\u0440\u0435\u0437 L2 \u0438 L3-\u0441\u0435\u0442\u0438. \u041e\u0441\u043d\u043e\u0432\u043d\u044b\u043c\u0438 [&hellip;]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":77042,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[688],"tags":[],"class_list":["post-77041","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-administrirovanie"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 5.0.2.1 - aioseo.com -->\n\t<meta name=\"description\" content=\"\u0412\u0432\u0435\u0434\u0435\u043d\u0438\u0435 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