[Detnet] Re: New Version Notification for draft-varga-detnet-srv6-data-plane-03.txt

[Balázs Varga A <[e-mail]>]

Hi Shaofu,

Many thanks for your clarification question.

The allocation characteristics of Flow-ID is independent from the DetNet
data plane encapsulation. Flow-IDs are allocated locally and this nature is
explicitly referred in the data plane documents, e.g., in RFC8964 in Section
‘4.2.2.  S-Labels’:
“ … S-Labels are local to each node,
   rather than being a global identifier within a domain, they must be
   advertised to their upstream DetNet service-aware peer nodes (i.e., a
   DetNet MPLS end system or a DetNet relay or edge node) and
   interpreted in the context of their received F-Label(s).”

Same characteristics applies for the SRv6 data plane encapsulation, where
Flow-ID is encoded in the ARG part of the Redundancy SID. It is defined in
your referred text.

Regarding your question, “why local”: allocating local values allow better
flexibility. An APP flow may have several Member flows along the PREOF-path.

Please note, that nothing prohibits You to use globally unique values in a given
network scenario, if there are no related concerns.

A possible Flow-ID allocation example for the Figure-3 network:
(Note: in this example a Flow-ID is 20 bits, “NNNN” refers to a 16 bit SeqNum)
- E5: Flow-ID = 00001x (local),
   results in following Redundancy SID value: 2001:db8:K:5:P:0000:1NNN:N000
   (packet routed based on 2001:db8:K:5/64 routing table entry pointing to node E5)
- R2: Flow-ID = 00002x
   results in following Redundancy SID value: 2001:db8:K:2:P:0000:2NNN:N000
   (packet routed based on 2001:db8:K:2/64 routing table entry pointing to node R2)
- E6: Flow-ID = 00002x
   results in following Redundancy SID value: 2001:db8:K:6:P:0000:2NNN:N000
   (packet routed based on 2001:db8:K:6/64 routing table entry pointing to node E6)

Thanks & Cheers
Bala’zs



From: [e-mail] <[e-mail]>
Sent: Tuesday, February 3, 2026 3:33 AM
To: Balázs Varga A <[e-mail]>
Cc: [e-mail]
Subject: Re: [Detnet] Re: New Version Notification for draft-varga-detnet-srv6-data-plane-03.txt




Hi Bala'zs,



Thanks for sharing this document.



After reading the document, I still have quesitons about the setting of flow-id and don't understand how it works.



There is some text in the document as below:

"

Flow-IDs MUST be allocated by the entity that controls the service sub-layer receiving node's Flow-ID space.  Because Flow-IDs are local to each node rather than being a global identifier within a domain, they MUST be advertised to their upstream DetNet service-aware peer nodes (i.e., a DetNet SRv6 End System or a DetNet Relay or Edge Node).

"



My quesiton is: why is flow-id designed to be local rather than global? Seems it brings unnecessary complex about flow-id advertisement, inconsistency of identifying the same APP flow.



Can you give some illustrations on how to set flow-id based on the example topology (fig 3 of draft-ietf-spring-sr-redundancy-protection-05) ?



Regards,

PSF


Original
From: BalázsVargaA <balazs.a.varga=[e-mail]<mailto:balazs.a.varga=[e-mail]>>
To: DetNet WG <[e-mail]<mailto:[e-mail]>>;
Date: 2026年02月03日 01:31
Subject: [Detnet] Re: New Version Notification for draft-varga-detnet-srv6-data-plane-03.txt
Hi,

Changes in the new version of the "Deterministic Networking SRv6 Data Plane" draft
https://datatracker.ietf.org/doc/draft-varga-detnet-srv6-data-plane/
was made in order to be fully in-line with the Spring WG Redundancy Protection draft

The technical contents of the draft is quite stable, thanks for all the feedbacks during
its discussions.

Please, provide your review if you have any questions/comments/possible improvements.
Supportive feedbacks are also welcome.

Thanks & Cheers
Bala'zs

Ps: the Spring WG Redundancy Protection draft is available here:
https://datatracker.ietf.org/doc/draft-ietf-spring-sr-redundancy-protection/

-----Original Message-----
From: [e-mail]<mailto:[e-mail]> <[e-mail]<mailto:[e-mail]>>
Sent: Sunday, February 1, 2026 1:46 PM
To: Balázs Varga A <[e-mail]<mailto:[e-mail]>>; Ferenc Fejes <[e-mail]<mailto:[e-mail]>>
Subject: New Version Notification for draft-varga-detnet-srv6-data-plane-03.txt

A new version of Internet-Draft draft-varga-detnet-srv6-data-plane-03.txt has been successfully submitted by Balazs Varga and posted to the IETF repository.

Name:     draft-varga-detnet-srv6-data-plane
Revision: 03
Title:    Deterministic Networking SRv6 Data Plane
Date:     2026-02-01
Group:    Individual Submission
Pages:    17
URL:      https://www.ietf.org/archive/id/draft-varga-detnet-srv6-data-plane-03.txt
Status:   https://datatracker.ietf.org/doc/draft-varga-detnet-srv6-data-plane/
HTMLized: https://datatracker.ietf.org/doc/html/draft-varga-detnet-srv6-data-plane
Diff:     https://author-tools.ietf.org/iddiff?url2=draft-varga-detnet-srv6-data-plane-03

Abstract:

   This document specifies the Deterministic Networking (DetNet) data
   plane when operating over an IPv6/SRv6 Packet Switched Network.  It
   leverages existing IPv6 encapsulations and behaviors.  It uses the
   Redundancy SIDs in DetNet scenarios and optionally the Traffic
   Engineering mechanisms provided by SRv6.  This document builds on the
   DetNet architecture and data plane framework.



The IETF Secretariat


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