1. Sasha Vainshtein, Yaakov Stein
IETF-58 PWE3 Working Group Structure-Agnostic TDM over Packet draft-ietf-pwe3-satop-00.txt Summary and Open Issues
Sasha Vainshtein, Yaakov Stein
11/20/2018
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:
11/20/2018
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
11/20/2018
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
11/20/2018
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
11/20/2018
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?
11/20/2018
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!
11/20/2018
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
11/20/2018
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
11/20/2018
IETF-58 Minneapolis

10. Questions?
11/20/2018
IETF-58 Minneapolis