IETF-58 PWE3 Working Group Structure-Agnostic TDM over Packet draft-ietf-pwe3-satop-00.txt Summary and Open Issues

1. IETF-58PWE3 Working GroupStructure-Agnostic TDM over Packetdraft-ietf-pwe3-satop-00.txtSummary and Open Issues Sasha Vainshtein, Yaakov Stein IETF-58 Minneapolis

2. 4 months ago in Vienna… • From the PWE3 Session Minutes: • Yaakov Stein and Sasha Vainshtein to produce a joint unstructured draft by 1st September • … • Yaakov Stein and Sasha Vainshtein invited to re-present their structured work as individual drafts • This decision resulted in: IETF-58 Minneapolis

3. SAToP-00 • A common draft co-edited by Yaakov and Sasha • A new term - "struture-agnostic" coined to reflect the essence • Co-authors: • Motti Anavi, Tim Frost, Eduard Metz, Prayson Pate, Akiva Sadovski, Israel Sasson, Ronen Shashoua • Posted as an individual submission on 04-Sep-03 • Multiple positive responses on the list • Some issues raised during the discussion • Adopted as a WG item 23-Sep-03 • Open issues listed in the re-submitted text • WG input solicited for their resolution IETF-58 Minneapolis

4. SAToP-00 (2) • Supports E1/T1/E3/T3 TDM bit-streams • Fixed-size chunks of the TDM bit stream packetized • Default packet size specified per service • Any packet size can be used if agreed upon • A control word is mandatory: • The generic PWE3 CW is used • Sequence number follows the RTP rules: • Circular 16-bit space without any gaps • Two flags: • L - forward indication of the local AC failure • Payload MAY be omitted • R - backward indication of PSN failure IETF-58 Minneapolis

5. SAToP-00 (3) • RTP header can be optionally used • Positioned differently for IP and MPLS PSN: • IP: immediately PRECEDES the CW to resemble the classic RTP • MPLS: immediately FOLLOWS the CW to be ECMP-safe • Same sequence number used in both the CW and RTP header • Two modes of time-stamping: • Absolute - the time-stamping clock is the line clock of the local AC • Differential - the time-stamping clock is a high-quality clock available at both ends of the PW IETF-58 Minneapolis

6. Issue: "Octet-Aligned T1" • Raised by Ron Cohen and Yaron Raz • Modern NSPs often extract (unstructured!) T1 mapped to 25 timeslots within a (structured) E1 • The mapping is defined in ITU-T G.802 (Annex B) • Relevant NSPs: SONET/SDH mappers etc. • Integration with SAToP is problematic: • Carrying an entire E1 using SAToP is BW-expensive • De-mapping T1 from E1 requires additional HW • Proposals (WG input is solicited): • Add a special mode in SAToP? • Define a new "octet-aligned T1" service? • What else? IETF-58 Minneapolis

7. Issue: "T3 AIS" • Raised by Alex Conta: • T3 AIS cannot be detected/generated in a structure-agnostic way: • Requires T3 framing • No such problem with the rest of the services (E1, T1, E3) • AIS is important for SAToP: • Detection allows BW saving • Generation is desirable in case of AC and PSN failures • The current solution ("all ones") indicates a problem but not the specific problem • Proposal (WG input is solicited): • Direct indication of TDM validity! IETF-58 Minneapolis

8. Issue: "A reference to the EF PHB" • Raised by the Editors • Using EF PHB in SAToP PWs seems natural • E.g., see draft-baker-basic-diffserv-classes • Appropriate limitations can be explicitly defined • The DiffServ WG co-chairs objected to naming any specific PHB in the QoS section of TDM drafts • This authoritative ruling has been accepted • The doubts remain • The WG input and the ADs guidance are solicited • The DiffServ WG has concluded IETF-58 Minneapolis

9. What Remains to Be Done • Resolve the open issues • Allocate the service type code points for the SAToP-supported services • Provide a SAToP MIB • Will be done in a dedicated draft • Add RTP-specific parameters to the PWE3 control protocols • Will be done as: • A single dedicated draft in this WG? • Two control protocol-specific drafts in different WGs? • Go to the WG Last Call before the next IETF IETF-58 Minneapolis

10. Questions? IETF-58 Minneapolis