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

2. Agenda IEEE1588/PTP Status Protocol overview Transparent clocks
TICTOC and PWE3

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

4. Protocol overview Timing Protocol
Align slaves to master time
Measure delay between master and slave
Measure per-link delay (v2)
Synchronization Hierarchy ‘routing’ Protocol
Automatic Best Master Clock Algorithm
Determines the master-slave synchronization clock tree hierarchy
Management Protocol
Configuration and performance monitoring

5. PTP Master-Slave Hierarchy
*Clock symbols taken from ITU-T SG15 ‘synchronization modeling components – time’ contribution #249 Geneva-2007 by Mike Gilson of BT

6. Timing Protocol Operation

7. Peer Delay Measurement (Optional)

8. End-to-End Transparent Clocks
E2E TCs cancel queuing and processing delays

9. Peer-to-Peer Transparent Clocks
P2P TCs cancel queuing, processing and propagation delays

10. Packet queuing and processing is removed
E2E TC Enabled PSN
Packet queuing and processing is removed

11. Topology change does not effect slave performance
P2P TC Enabled PSN
Topology change does not effect slave performance

12. An application: Use of IEEE1588 for CES
PEs use IEEE1588 clock as common reference
E1/T1 service clock delivered using differential timing

13. PWE3 Architecture (single hop)
Properties
Emulates a native service
IWF implemented at Provider Edge
PSN is unaware
Service and PW is bidirectional

14. PWE3 Architecture (multi-hop)
Properties
PW stitching used for to provide inter-provider services
PW stitching for in intra-provider network mainly in aggregation scenarios

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

16. Summary
There are commonalities and differences between PWE3 and TICTOC
We should figure out the relationship between TICTOC and PWE3 in the following areas:
PW architecture
PW MIB
PW signaling
TICTOC protocol mapping to MPLS/L2TP

17. Ron Cohen Resolute Networks ronc@resoluteNetworks.com
Thank You
Ron Cohen
Resolute Networks