Dear SPRING Chairs, IDR Chairs and all,

As a coauthor of this draft, I look forward to inputs from both the SPRING and 
IDR working groups.


The problem addressed by this draft is important for network operators, 
especially large-scale operators such as China Mobile, which runs networks with 
thousands of devices and has widely deployed SRv6 Policies in production 
networks.
We need to collect real-time state information for deployed SR policies. If we 
use BGP-LS for this purpose, it would require establishing BGP-LS sessions 
between every headend node and the SDN controller. Although BGP-LS is being 
extended to report SR policy state, we believe that BGP SR Policy provides an 
alternative approach that is more suitable for large-scale networks with 
widespread SR policy deployments. OPEX complexity and operational burden can be 
significantly reduced, since the same protocol used for SR policy distribution 
can also be used for state reporting.


Regarding the first question raised by Liyan, I think it is primarily for 
SPRING. In my view, the answer is clearly yes, as solutions for SR policy state 
reporting are already being developed in BGP-LS, YANG push, and PCEP.
For the second question, I believe it falls primarily within IDR’s scope once 
the requirements are confirmed by SPRING. The rationale for proposing BGP SR 
Policy to report SR policy state is elaborated in the draft and summarized 
above.


Further comments and discussion are welcome. Thank you all in advance.



Zhenqiang
China Mobile



----邮件原文----

发件人:"宋力焱" <[email protected]>

收件人:idr-chairs <[email protected]>,spring-chairs <[email protected]>,idr 
<[email protected]>,spring <[email protected]>

抄 送: lizhenqiang <[email protected]>,songguangchenjc 
<[email protected]>

发送时间:2026-03-30 14:08:39

主题:Input requested: SR Policy state reporting requirement






Dear WG chairs and all,




Following discussions in IDR (including feedback from the IDR chairs), we would 
like to seek input from SPRING on the requirement and direction for SR Policy 
state reporting.




We observe that there is currently no standard mechanism to report SR Policy 
operational state (Policy / Candidate Path / Segment List) from headend nodes 
to a controller in a structured and hierarchical manner. Existing approaches 
(e.g., BGP-LS, YANG) either require additional protocol mechanisms or do not 
align well with SR Policy constructs. In particular, they may require 
controllers to establish additional sessions (e.g., YANG) with headend nodes.




To address this, we are working on a draft: 
https://datatracker.ietf.org/doc/draft-li-idr-bgp-sr-policy-state-report/ . The 
draft extends BGP SR Policy (as defined in RFC 9830) to carry state 
information, allowing both policy provisioning and state reporting within the 
same framework, thereby reducing protocol overhead and simplifying operations.




Before proceeding further, we would like to confirm:

1. Is such a requirement considered valid in SPRING?

2. Is extending BGP SR Policy an appropriate direction for this problem?




The authors and the IDR WG chairs would greatly appreciate feedback and 
guidance from the SPRING WG. Any additional comments are also very welcome.




Best regards,

Liyan Song 















 


 








 
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