Markdown Version | Session Recording

Session Date/Time: 22 Jul 2024 16:30

schc

Summary

This session covered several key aspects of the schc (Static Context Header Compression) protocol, including updates to the architecture document, discussions on multicast, presentations on specific implementations (OAM, 15.4 networks, CoAP, and ESP header compression), and a call for adoption of a draft concerning schc in disruption-prone networks. A new open-source schc implementation was also introduced.

Key Discussion Points

• schc Architecture:
  • The need to move away from LPWAN-centric architecture to a more generic schc architecture was discussed.
  • A new element called "schc Network Gateway (RSNG)" was introduced as the boundary between a schc network and a non-schc network.
  • The concept of a "schc instance" (two endpoints sharing the same rule set) was discussed, including whether it should be limited to two endpoints or accommodate multicast scenarios.
  • The introduction of "stratum" as a grouping of a schc instance and a schc stratum instance (for management) was explained to avoid confusion with OSI layers.
  • The role of a "discriminator" in identifying the schc stratum instance to use was discussed.
• Multicast:
  • The applicability of schc in multicast scenarios was discussed. The conclusion was to focus primarily on point-to-point associations within schc instances, and then address potential extensions to point-to-multipoint scenarios in a separate section, acknowledging potential complexities.
  • It was suggested to examine Stuart Cheshire's work on multicast ports as a possible application of schc.
• OAM Draft:
  • The action part was removed from the OAM draft to reach consensus.
  • A new adoption call for the OAM draft will run for two weeks.
• 15.4 Networks:
  • The integration of schc with 15.4 networks was presented with emphasis on Single Instance Networks vs Multiple Instance Networks.
  • Impact on the need of the presence of schc stratum header based on which instance needs to be used to compress or decompress data unit.
  • The discussion also covered route over modes, mesh under and the transition protocol stack.
• CoAP Compression:
  • Updates to the CoAP header compression draft (Use of schc for compressing CoAP headers) including addressed errata, clarification on co-op option handling and a complete first version of a Young Data Model.
  • The definition of a catalog of co-op operator fields and pointers to specific documents that define how those are handled with schc in any known way.
• ESP Header Compression:
  • A novel approach to compressing ESP (Encapsulation Security Payload) headers using multiple levels or "strata" of compression.
  • The approach covered compression of the inner IP packet, cleartext ESP fields, and encrypted ESP fields.
• schc for Disruption-Prone Networks:
  • A draft on schc for networks susceptible to disruptions (energy harvesting and satellite networks) was presented and a call for adoption was extended.
• Open Source SHIC Implementation:
  • A new open-source schc implementation, Labshik, including a full SDK, DTLS implementation, rule implementation and synchrony functionality, available at Lab-shik.fr. and hosted on Gitlab.

Decisions and Action Items

• Action Item: Start a new adoption call for the OAM draft for two weeks.
• Action Item: Add a separate section in the architecture document to address potential extensions to point-to-multipoint scenarios.
• Decision: Adopt the draft on schc for disruption-prone networks, given the six plus ones and no negative votes.
• Action Item: Pascal to create a repo under the LP1 GitHub organization for the Yuzikshik sources.
• Action Item: Publish a zero zero version as soon as possible for the draft on schc for disruption-prone networks.
• Action Item: Mail to mailing list for discussion of whether STU should be renamed SDU

Next Steps

• Continue discussions on schc architecture and multicast handling on the mailing list.
• Publish version 00 of the schc for Disruption-Prone Networks draft.
• Further develop the architecture document incorporating discussed changes and additions
• Encourage community participation in the Labshik open-source project.
• Continue development of the ESP header compression draft.