TEAS - Traffic Engineering Architecture and Signaling

IETF 119 - Brisbane, Australia Chairs: Pavan Beeram, Oscar Gonzalez de Dios Secretary: Italo Busi

Summary

The TEAS Working Group (WG) met at IETF 119 to review the status of its extensive document portfolio and discuss several key technical areas including Network Resource Partitions (NRP), power-aware traffic engineering, and multipath TE. Highlights included the publication of RFC 9889 and significant progress on the core YANG models for TE and TE Topology. The group also addressed feedback from 3GPP liaisons regarding network slicing and discussed the intersection of TE with the emerging GREEN work.

Key Discussion Points

WG Status and Administrivia

RFC Published: RFC 9889 (Realization of Network Slices in IP/MPLS Networks).
IESG Evaluation: draft-ietf-teas-yang-te and draft-ietf-teas-te-types are addressing DISCUSS comments. Pavan Beeram noted that the scoping of the TE YANG model to LSP-based technologies was clarified and a revision is forthcoming.
Post-WGLC: draft-ietf-teas-yang-path-computation and draft-ietf-teas-yang-te-mpls-topology are awaiting minor editorial touches before progressing to the RFC Editor queue.
Liaisons: Responses were received from 3GPP RAN3 and SA. RAN3 feedback regarding terminology was incorporated, while a response to the SA liaison is still being drafted.

03 IETF Network Slice Application in 3GPP 5G End-to-End Network Slice

Presenter: Luis Miguel Contreras Murillo

Discussion: The update to draft-ietf-teas-5g-network-slice-application focused on 3GPP RAN3 feedback. There was a terminology conflict between 3GPP and O-RAN regarding concepts like "midhaul" and functional entities (DU/CU).
Outcome: The authors added text clarifying that 3GPP and O-RAN specifications take precedence for their respective definitions. Figures were updated to remove specific organizational labels to avoid confusion. The authors still need to address the 3GPP SA liaison received in December.

04 YANG Data Models for Network Resource Partitions (NRPs)

Presenter: Bo Wu

Discussion: draft-ietf-teas-nrp-yang version 05 resolved several open issues, including alignment with MPLS Network Action (MNA) selectors defined in draft-ietf-mpls-mna-hdr.
Scalability: The model now includes guidance for the planning, provisioning, and monitoring phases to support better scalability of NRPs.
Status: The authors believe the document is ready for Working Group Last Call (WGLC), though Pavan Beeram noted that draft-ietf-teas-nrp-scalability and draft-ietf-teas-ns-ip-mpls should ideally progress first.

05 Profiles for Traffic Engineering (TE) Topology Data Model and Applicability to non-TE-centric Use Cases

Presenter: Italo Busi

Discussion: The draft draft-ietf-teas-te-topology-profiles aims to clarify how RFC 8795 can be used for non-TE-centric applications (e.g., microwave networks).
Tooling: There was a debate regarding whether "programmatic profiling" (cutting YANG trees via tools) belongs in TEAS, ASNM, or NETMOD. Oscar Gonzalez de Dios suggested coordination with the ASNM BOF/Working Group.
Decision: Tooling will be kept out of scope for this draft. The document is considered stable and nearing WGLC.

06 Applicability of Abstraction and Control of Traffic Engineered

Presenter: Dan King

Discussion: draft-ietf-teas-actn-poi-assurance addresses monitoring multi-layer services (Packet over Optical).
Technical Detail: Discussion centered on the interaction between the Multi-Domain Service Coordinator (MDSC) and Provisioning Network Controllers (PNCs). A key question is how much lower-layer decision-making the MDSC should influence when failures or degradations occur. The authors are evaluating OAM mechanisms like BFD, STAMP, and TWAMP for cross-layer correlation.

07 A Power Conserving Path Placement Strategy (PCPPS)

Presenter: Tony Li

Discussion: draft-li-teas-pcpps proposes a power-aware CSPF enhancement to consolidate traffic and allow powering down unused ASICs/links.
Contention: Zafar Ali raised concerns about the definition of power metrics and potential overlap with the GREEN working group. Tony Li clarified that this work focuses on TE path placement (local headend computation) and uses metrics already defined in LSR, whereas GREEN focuses on monitoring.
Resilience: Dan King questioned how power-saving modes interact with network resilience. Tony Li noted that operators should maintain a bi-connected "minimal backbone" that never sleeps.

08 Multipath Traffic Engineering

Presenter: Pavan Beeram

Discussion: Updates were provided on the MP-TE suite: draft-ietf-teas-multipath-te, draft-ietf-teas-rsvp-multipath-te, and draft-ietf-teas-multipath-te-yang.
New Mechanism: The drafts introduced "hop versioning" to optimize signaling. This allows for in-place updates of subgraphs within a Directed Acyclic Graph (DAG) without impacting the entire structure, reducing trigger message churn.
Critique: Zafar Ali questioned the necessity of DAG-based TE given existing Segment Routing (SR) ECMP/UCMP capabilities. Pavan Beeram argued that MP-TE provides advanced bandwidth engineering that current SR implementations may struggle to achieve at scale.
Next Steps: An implementation report is expected at IETF 120 in Vienna.

09 5QI to DiffServ DSCP Mapping Example for Enforcement of 5G End-to-End Network Slice QoS