Precision Time Protocol (aka IEEE1588) TICTOC and PWE3 PWE3 WG IETF Prague 2007 Ron Cohen Resolute Networks ronc@

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  • Precision Time Protocol (aka IEEE1588)TICTOC and PWE3

    PWE3 WG IETF Prague 2007

    Ron Cohen Resolute Networksronc@resolutenetworks.com

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    AgendaIEEE1588/PTP StatusProtocol overviewTransparent clocksTICTOC and PWE3

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    The Precision Time Protocol (PTP)PTPv1 published in 2002Industries involved: v1: Industrial Automation, T&M, Military, Power Generation and Distribution v2 : Audio-Visio Bridges (802.1AS), Telecom and MobileSymposia in 2003, 2004, 2005, and 2006. 2007 in ViennaProducts: Microprocessors, GPS Linked Clocks, Boundary Clocks, NIC Cards, Protocol Stacks, RF Instrumentation, Aircraft Flight Monitoring Instruments, etc.Information: http://ieee1588.nist.govVersion 2 PAR approved March 2005. Technical work completed

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    Protocol overviewTiming ProtocolAlign slaves to master timeMeasure delay between master and slaveMeasure per-link delay (v2)Synchronization Hierarchy routing ProtocolAutomatic Best Master Clock AlgorithmDetermines the master-slave synchronization clock tree hierarchy Management ProtocolConfiguration and performance monitoring

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    PTP Master-Slave Hierarchy*Clock symbols taken from ITU-T SG15 synchronization modeling components time contribution #249 Geneva-2007 by Mike Gilson of BT

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    Timing Protocol Operation

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    Peer Delay Measurement (Optional)

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    End-to-End Transparent ClocksE2E TCs cancel queuing and processing delays

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    Peer-to-Peer Transparent ClocksP2P TCs cancel queuing, processing and propagation delays

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    E2E TC Enabled PSNPacket queuing and processing is removed

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    P2P TC Enabled PSNTopology change does not effect slave performance

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    An application: Use of IEEE1588 for CESPEs use IEEE1588 clock as common referenceE1/T1 service clock delivered using differential timing

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    PWE3 Architecture (single hop)

    PropertiesEmulates a native serviceIWF implemented at Provider EdgePSN is unawareService and PW is bidirectional

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    PWE3 Architecture (multi-hop)

    PropertiesPW stitching used for to provide inter-provider servicesPW stitching for in intra-provider network mainly in aggregation scenarios

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    TICTOC properties

    IEEE1588 (and TICTOC in general)Provides frequency and time services. Can be used for emulating existing services as well as enable new servicesPSN can be unaware or can be enhanced by introducing boundary and transparent clocksTiming and time services are mostly unidirectional, however the timing protocol is bidirectionalTiming and time services are required mostly within a single provider, from central locations to the provider edgesDelivering time and timing services between providers is of no interestBoundary clock (or Transparent clocks) probably required for aggregation scenarios within a provider network

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    SummaryThere are commonalities and differences between PWE3 and TICTOCWe should figure out the relationship between TICTOC and PWE3 in the following areas:PW architecturePW MIBPW signalingTICTOC protocol mapping to MPLS/L2TP

  • Thank YouRon CohenResolute Networksronc@resoluteNetworks.com

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