idr Session

Summary

The IDR session covered several draft updates and new proposals. Key topics included VGPL SR draft status, flow spec V2 splitting, 5G metadata path attribute updates, BGP finite state machine considerations, BFD strict mode, BGP Quick, generic metrics for BGP, SR policy for composite kinetic paths, time range weights for BGP SRV6 policy, and link bandwidth extended communities. A new proposal on Turner Equip Point was also discussed.

Key Discussion Points

VGPL SR Drafts: Updates on the four drafts. One draft was removed. Chair reviews are pending.
Draft IETFB, BGP, inter-AS topology 16: John was requested to review.
Draft IDR 5G edge service metadata: Shepherds reviewing it and expecting it to be done soon.
Flow Spec V2: Discussion on splitting the large flow spec draft into smaller, more manageable chunks for easier implementation.
- IP flow spec for DDoS as a minimal subset carrying over the V1 actions and filters.
- Extended filters including dependencies between filters.
- New actions to extend community actions and add wide community actions.
- Consideration of packet filters in addition to link data.
- Discussion of making component IDs global vs. local to the filter type.
5G Metadata Path Attribute: Update on major changes, including the addition of an AS Scope sub-TLV to prevent unintended leaking to ASs. The discussion included mismatch checking and route churn considerations. A question was raised about the necessity of applying a new SAFI, for the ingress router and the working group feedback requested on that.
BGP Finite State Machine: Discussion on the complexity of maintaining the BGP state machine, especially with added features. The conversation touched upon substates, management exposure, and the need for better documentation.
BFD Strict Mode: An update on the BFD strict mode feature, including sub-states for all the places where we would transition into open confirm. The goal is to ensure proper synchronization between BFD and BGP state machines.
BGP Quick: BGP over QUIC was presented, highlighting its resilience benefits due to multiple streams. Each stream is per AFI-SAFI, which also helps for prioritization of each of these address families. Detailed finite state machines for the control and function channels were presented. Security and TLS 1.3 were mentioned.
Generic Metric for BGP: Updates on the draft leveraging the next-hop capability attribute (NHC) to carry accumulated metrics. The discussions included specifying intent with multiple metric types, updating metrics along the path, and detecting discontinuity.
SR Policy for Composite Kinetic Paths: Discussion about extending BGP to distribute SR policies carrying composite candidate pass information. This information can be used to load balance traffic over a set of sub-SR policies.
Time Range Weights for BGP SRV6 Policy: The proposal introduces a time-weight attribute in BGP to pre-configure bandwidth resource allocation. Concerns were raised about the relationship with time variant routing and where it should be done (Spring vs. IDR).
Link Bandwidth Extended Communities: There were two presentations on the link bandwidth extended community with overlapping but different focuses. One focused on moving from 32bit to 64bit bandwidth, the other on the transitivity question of the legacy bandwidth attribute. Discussion focused on interoperability issues and what has already been deployed.
Source Metric Distribution based on BGP in CAS Network: This solution defines a new BGP address family to dispute the computing service metric information and a variable Lens NRI related to distinguish between key and non-key paths.
BGP Extension for Turner Equip Point: This proposal is about addressing the traffic scheduling for AI bursts on load sharing individual packets of the same flow which requires reordering based on the Turner Equip Point information from the remote end.

Decisions and Action Items

VGPL SR Drafts: Authors to address chair review concerns.
Draft IETFB, BGP, inter-AS topology 16: John to review.
Draft IDR 5G edge service metadata: Finish shepherd review.
Flow Spec V2: Continue discussion on breaking up the draft and defining filter chains and action templates.
5G Metadata Path Attribute: Working group feedback requested on applying for a new SAFI
BFD Strict Mode: Implementers to make tweaks to the code and verify against the state machine.
BGP Quick: Specify the QUIC TLS version in the document.
Generic Metric for BGP: Authors to consider renaming "capability" due to overloading. Address EBGP questions about metrics.
Time Range Weights for BGP SRV6 Policy: Coordinate with the time-variant routing working group.
Link Bandwidth Extended Communities: Try to merge existing work for this one. It was advised the EVPN work has real user cases.
BGP Extension for Turner Equip Point: Clarify the motivation and architecture.

Next Steps

Continue discussion on Flow Spec V2 splitting.
Address pending chair reviews for VGPL SR drafts.
Implement changes and verify BFD Strict Mode.
Investigate QUIC TLS version in the document
Address comments on the draft about Generic Metrics for BGP
Coordination with time-variant routing WG to align the work for BGP SRV6 Policy weights with the time.
Merge existing work on Link Bandwidth Extended Communities.
Review architectural impact.

Session Date/Time: 26 Jul 2024 22:30

idr

Summary

The IDR working group meeting covered several topics including a report on the interim meeting, FlowSpec, route redistribution, SD-WAN, and B4/B6. A primary focus was on achieving a base FlowSpec with user ordering and dividing the FlowSpec specification into manageable parts. Discussions involved adoption calls, new filter proposals, action changes, and drafts related to redirect. Several individuals presented their drafts and updates, with discussion around implementation details, scalability, and the interplay between different specifications.

Key Discussion Points

FlowSpec V2 Decomposition: Splitting FlowSpec V2 into smaller, manageable drafts: IP Basic (minimal subset with user ordering), more filters (dependency filters), and more IP actions (action change).
FlowSpec V1 and V2 Coexistence: Addressing the coexistence of FlowSpec V1 deployments with potential migration to V2. Recommendation to deploy V2 if not already using V1.
User Ordering and Component Numbering: Debate on how to number components within FlowSpec and the need for a default sort order, including the possibility of gaps for future insertions. Jeff Haas provided a detailed explanation of why this is important.
INA Registry: The group had a brief discussion about the registry design.
Filter Dependencies: Exploration of filter dependencies and shortcuts to improve processing efficiency.
Action Changes and Failure Modes: Discussing how to handle action failures (e.g., traffic limiting, DSCP marking, redirects) and the potential for "all or nothing" vs. "best effort" approaches.
Capabilities Advertisement: Discussion on how to indicate which features an implementation supports and how to handle cases where some network portions don't support specific features.
VRF and Data Plane Concerns: Jeff Haas emphasized that rules should only filter on what is unambiguous in the data plane to avoid a recipe for disaster.
Hardware Limitations: Awareness of hardware table overflows and the need for predictable behavior, like a notification if programming fails.
SAUO Rule Distribution: Nang-Gong presented a use case for BGP FlowSpec for source address validation and raised discussion points about scalability and interface set placement.
Packet Content Filter: Yusha presented a packet content filter for BGP FlowSpec, outlining its use cases and test results.
Route Redistribution and Deterministic Behavior: Anchor Chen presented on the uncoordinated route selection algorithm in RIP and BGP interaction, aiming to make the behavior deterministic. Jeff Haas challenged if this should be a normative practice for BGP, as implementations exist without the problem.
Multi-Segment SD-WAN: Chongfen presented a simple extension to BGP for carrying the associated gateway exchange in multi-segment SD-WAN.
IPv6 Transition: Shia Chongfong updated the BGP extension for IPv4 service delivery in IPv6-only networks.
4P updates: Guyin Mishra updated the group on updates to the 4P draft.

Decisions and Action Items

Working Group Adoption Call: IP Basic draft is under working group adoption call. Feedback is needed on the format and dependency chain.
Capabilities: The working group recognized the need for capabilities beyond the basic specification (V1 + ordering).
List Discussion: The group agreed that the interaction between BGP and Admin Distance should be discussed further on the list.

Next Steps

Implementers to review and provide feedback on the IP Basic draft.
Continue discussions on extended filters and actions to drive adoption.
The working group will address capabilities beyond the basic specification.
Address and discuss implementation details on the mailing list.
Individual presenters to update their drafts based on the meeting discussion.