Title: Precision%20Time%20Protocol%20(aka%20IEEE1588)
1Precision Time Protocol (aka IEEE1588)
- TICTOC and PWE3
- PWE3 WG IETF Prague 2007
- Ron Cohen
- Resolute Networks
- ronc_at_resolutenetworks.com
2Agenda
- IEEE1588/PTP Status
- Protocol overview
- Transparent clocks
- TICTOC and PWE3
3The Precision Time Protocol (PTP)
- PTPv1 published in 2002
- Industries involved
- v1 Industrial Automation, TM, Military, Power
Generation and Distribution - v2 Audio-Visio Bridges (802.1AS), Telecom and
Mobile - Symposia in 2003, 2004, 2005, and 2006. 2007 in
Vienna - Products Microprocessors, GPS Linked Clocks,
Boundary Clocks, NIC Cards, Protocol Stacks, RF
Instrumentation, Aircraft Flight Monitoring
Instruments, etc. - Information http//ieee1588.nist.gov
- Version 2 PAR approved March 2005. Technical work
completed
4Protocol 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
5PTP Master-Slave Hierarchy
Clock symbols taken from ITU-T SG15
synchronization modeling components time
contribution 249 Geneva-2007 by Mike Gilson of
BT
6Timing Protocol Operation
7Peer Delay Measurement (Optional)
8End-to-End Transparent Clocks
E2E TCs cancel queuing and processing delays
9Peer-to-Peer Transparent Clocks
P2P TCs cancel queuing, processing and
propagation delays
10E2E TC Enabled PSN
Packet queuing and processing is removed
11P2P TC Enabled PSN
Topology change does not effect slave performance
12An application Use of IEEE1588 for CES
PEs use IEEE1588 clock as common reference E1/T1
service clock delivered using differential timing
13PWE3 Architecture (single hop)
Properties
Emulates a native service
IWF implemented at Provider Edge
PSN is unaware
Service and PW is bidirectional
14PWE3 Architecture (multi-hop)
Properties
PW stitching used for to provide inter-provider services
PW stitching for in intra-provider network mainly in aggregation scenarios
15TICTOC 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
16Summary
- 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
17Thank You
- Ron Cohen
- Resolute Networks
- ronc_at_resoluteNetworks.com