March 2008Tictoc Protocol Review1 NTP/1588 Protocol Review (Gap Analysis) IETF 71 Philadelphia Greg Dowd March, 2008

March 2008Tictoc Protocol Review2 NTP (Pros) Clock ensembling Strong/multi model authentication (server) Strong redundancy/clustering algorithms Multiple operating modes Extensive system level testing

March 2008Tictoc Protocol Review3 NTP (Cons) Timestamp specification ambiguity Polling Rate Limitations Stateless server requirement Rigid specification of clock pll (sntp?) Layer 3 implementation model Lack of on path support (intermediate stratum servers/boundary clocks)

March 2008Tictoc Protocol Review4 NTP (Cons) Few technical developers Ambiguous hardware timing support No performance metrics for time or frequency Path asymmetry issues One way authentication mechanism Monolithic conformance model (no “profile” ala 1588 except SNTP)

March 2008Tictoc Protocol Review5 NTP (Suggestions) Define client-only clock mode Extend NTP to support follow up msgs Extend NTP to support “profiles” Extend domain concept to allow interoperation of multiple ntp pools Propose definition of TC for NTP Formalize acceptance of state in server

March 2008Tictoc Protocol Review6 PTP (Pros) Hardware timestamping support widely available High sync rates Alternative timescale support Application specific profiles allowed Multiple models available (Multicast/ unicast/hybrids)

March 2008Tictoc Protocol Review7 PTP (Cons) GM Clock failure mitigation (phase hit) Single tier Authentication Mgmt of protocol state machine only No SNMP MIB for PTPv2 No performance metrics for time

March 2008Tictoc Protocol Review8 PTP (Cons) Follow up routing issues Path asymmetry issues Physical layer mapping issues on time transfer Path rate change issue for time transfer Decoupling of 2 halves of time transfer equation

March 2008Tictoc Protocol Review9 PTP (Suggestions) Create clustering/failover mechanism in unicast model Review TDD/FDD vs profiles Define slave “clock” mgmt messages Clarify TC frame updates vs layer 2/3 Review authentication impact on timing/hardware

March 2008Tictoc Protocol Review10 Common Suggestions Investigate time-transfer/symmetry metrics for routing protocols Create metrics for performance analysis (via ITU/pmol/ippm) Define IWFs for syncE Define time dispersion extensions for BCs