Simpler PTP - Optimized Precision Time Protocol (PTP) for Datacenters.pdf

1、Simplified Precision Time ProtocolSimpler PTPDeploymentsSimpler Precision Time Protocol(SPTP)Oleg Obleukhov,MetaAlexander Bulimov,MetaAhmad Byagowi,MetaIntroIn 2002,Precision Time Protocol(PTP)was introduced“as a successor for NTP”PTP is backed by the IEEE 1588 standardIEEE 1588-2019 is the latest r

2、evision,and it allows for wider definition of profilesMainstream profiles G8265.1 and G8275.2 which support unicastPTP unicast implementation uses several hand shaking messagesHand shaking messages are designed to balance the client load on the appliances Open Time Server removes most of the capacit

3、y constrains in traditional appliancesBackgroundBackgroundHow do you do time syncBackgroundServerClientt2-t1=delay+offsett4 t3=delay-offsetG8265.1 and G8275.2 support unicastHandshaking signaling1.Load Balancing2.Authentication3.Fault DetectionBackgroundClientServerAnnounce Grant RequestSync Grant R

4、equestDelay Request Grant RequestAnnounce GrantSync GrantDelay Request GrantTimeAnnounceSyncFollowupDelay RequestDelay ResponseT1T2T3T4Good Engineering!Simpler PTP removes all the unnecessary signaling1.Load BalancingNo longer an issue with open Time Server2.AuthenticationNot applicable inside a dat

5、a center3.Fault DetectionRedundancy of time server and clock quorumSimpler PTPClientServerTimeSyncAnnounce/FollowupDelay RequestT1T2T3T4Engineering for Good!Simpler PTP has number of advantages over traditional PTP that are especially important in Datacenters:1.No state on the server sideno subscrip

6、tions to maintain2.No complex state machines on client sideno subscriptions to start/renewsend one packet,receive two,done3.Data from multiple sourcesClient constantly receives time sync data from multiple GMs,making failover and monitoring easier Simpler PTP benefitsOpen Time ServerAppliances in th