Re： Comments Summary about SRv6 Midp oint Protection

Hi All,




From my point of view, I think the midpoint protection is necessary in the SRv6 network deployment, and this technology is also relatively mature. I hope to promote it as soon as possible.

In order to comply with RFC8200, it is recommended to restrict the implementation of midpoint protection only on endpoint nodes, and not on transit nodes. 










Best Regards


Yisong

 



发件人: Huzhibo

时间: 2023/03/08(星期三)14:59

收件人: RTGWG;ipv6;spring;

主题: [spring] Comments Summary about SRv6 Midpoint Protection 

 

Hi folks: 

  

Based on the discussions held at the 115th IETF meeting, we summarized the comments related to SRv6 midpoint protection, and then let's see how this document can be further move ahead. 

  

Q: how does SRv6 Midpoint protection differentiate the condition the route is not present vs. link down? IPv6 prefix not advertised, or not link down?  

A: SRv6 Midpoint Protection does not distinguish between Link Down and Node Down. Assume that the Node is Down to maximize the protection scope. 

  

Q: In SRv6, Some function maybe executed at Failure node, maybe accounting or rewrite? SRv6 midpoint protection may miss the execution of some necessary functions.like Security. 

A: A mechanism is needed to indicate whether an endpoint can be bypassed or not. [I-D.li-rtgwg-enhanced-ti-lfa] provides method to determine whether enable SRv6 midpoint protection or not by defining  a “no bypass” flag. which has been updated  in the document. 

  

Q: Here we are handling 2  times failure (One layer-3 adjacency interface and another primary interface), in all other cases we only handle one failure.Better to restrict to handling of one failure. 

A: layer-3 adjacency interface and primary interface may be the same interface. Therefore, It must be processed. 

  

Q: When the repair node is a transit node, it may be against RFC 8200 which won’t allow transit node to modify SRH. 

A: Only endpoint node can process SRH, Therefore, only endpoint nodes can perform midpoint protection. This complies with RFC 8200,.which has been updated in the document. 

  

Q:Only endpoint node perform midpoint protection depends on IGP convergence in some case. 

A: Only when loose paths depend on IGP convergence, To comply with RFC 8200 .We can only prohibit the execution SRv6 Midpoint protection on the transit node. However, the IGP convergence performance is much better than that of SRv6 Policy rerouting. 

  

Thanks 

  

Zhibo Hu

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