Session Date/Time: 25 Jul 2025 07:30

pce

Summary

The PCE (Path Computation Element) working group meeting covered a wide range of topics related to PCEP (Path Computation Element Protocol) extensions and updates. Presentations were given on drafts concerning algorithm descriptions, binding seed extensions, SRv6 SID list optimization, operational clarifications, stateful PCE amendments, reporting extensions, multipath traffic engineering (MPTE) DAG tunnels, topology filters, source address validation, precision availability metrics, PCEP over QUIC, and VLAN traffic forwarding. Several drafts were proposed for adoption and discussions were held regarding implementation details, backward compatibility, and potential conflicts with existing RFCs.

Key Discussion Points

Algorithm Descriptions in PSEP: Discussion focused on extending the SR ERO sub-object to support flexible algorithms and backward compatibility.
Binding Seed Extensions in PCET: Introduced new flags within the TP binding TLV to enhance flexibility in binding seed allocation, including fallback mechanisms and handling conflicts. Concerns were raised regarding clarity and suggested the addition of examples.
SRv6 SID List Optimization: The draft aims to address MSD (Maximum SID Depth) inefficiencies by allowing the PCE to ignore the first UA (Ultimate Adjacency) SID in MSD calculations. Discussion centered on whether this should be addressed with a flag or an RFC update.
Operational Clarifications: Updates focused on emphasizing the informational nature of the document and clarifying the distinction between PC reports and extended LSPDBs. Discussion arose on how to handle PC overload, with suggestions to throttle reports or selectively close sessions.
Stateful Amendment: Optimization draft which included removing the requirement to send PC Requests. Addressed the need for Manageability and Security guidelines.
Reporting Extensions: Introduced new flags for transit eligibility and explicitly specified paths, along with clarification on the use of loose and strict hops.
MPTE DAG Tunnels: Discussed extensions to enable PCC delegation of MPTE tunnels to the PCE and different modes of operation.
Topology Filters: New revisions clarifying Optional TLB's (TRIE's) and uses for algorithm ID's.
Source Address Validation: Introduced a PCEP extension to support source address validation and asked the question is PCEP the best solution and is the stateful model the right solution?
Precision Availability Metrics: Presentation on traffic engineering database using new metrics for paths satisfying service level objectives.
PCEP over QUIC: Authors updated document giving motivation, with Andrew giving objections, for doing it that way and the team were charged to keep speaking with all the authors working on a similar problem.
VLAN Traffic Forwarding: Presenting an draft about PSAP procedures and extension for villain traffic forward and some essential updates . It was also stated that not a lot of feedback was received on the draft so to give feedback on the mailing list.

Decisions and Action Items

Flex Grid Draft: Chairs to discuss with authors on the next step. Reminders have been sent, but no response was received. The option of moving the authors to acknowledgements was raised.
Algorithm Descriptions in PSEP: Samuel to update the document and allow time for feedback.
Binding Seed Extensions in PCET: Samuel to add examples to the document illustrating the use of the new flags.
SRv6 SID List Optimization: Discuss the topic further on the mailing list to determine the best approach for addressing the MSD inefficiency.
Operational Clarifications: Chairs asked about the consensus to do B or not C. Samuel also volunteered his suggestion of closing the session completely so the PC can selectively close some sessions. A question was raised to whether there needs to be two LSPDBs.
Reporting Extensions: Samuel to add examples about the terminology, about the transit LSP and the explicit vs dynamic path.
PCEP over QUIC: Presenter to keep working with other teams on similar issues.

Next Steps

Authors of drafts under discussion to incorporate feedback and update their documents.
Chairs to schedule working group last calls for documents deemed ready.
Continue discussions on the mailing list for unresolved issues and open questions.
Consider the different adoption proposals for the drafts presented during the meeting.