[spring] Re: Re： Re: Ask SPRING WG for review draft-liu-spring-sr-policy-flexible-path-selection

["jmh.direct" <[e-mail]>]

Rather than my trying to restate the problem, I would recommend reading Sent via the Samsung Galaxy S20 FE 5G, an AT&T 5G smartphone
-------- Original message --------From: Yisong Liu <[e-mail]> Date: 12/11/24  1:23 AM  (GMT-05:00) To: Joel Halpern <[e-mail]>, spring <[e-mail]> Cc: draft-liu-spring-sr-policy-flexible-path-selection <[e-mail]> Subject: Re： Re: [spring] Ask SPRING WG for review draft-liu-spring-sr-policy-flexible-path-selection Hi Joel,Thank you for your comments. I want to provide some clarity regarding the purpose and scope of this draft . This draft tackles the scenario where multiple paths are available, and the need arises to switch paths based on their quality metrics. It is not intended to replace the controller's role in global optimization but rather to complement it by allowing for local, quality-driven responses to link degradation.The draft specifically addresses the ability to switch to alternative paths within a strategy when the current path fails to meet specified link quality criteria such as bandwidth, delay, or packet loss. In cases where a controller issues an SR Policy that encompasses multiple paths, if a path's link quality does not meet the set requirements, it will switch to a backup path for forwarding.Essentially, this draft resolves the forwarding status of SR Policy paths, facilitating a switch based on link quality. It is important to note that the overall path optimization remains under the purview of the controller, which continues to make global decisions. This draft addresses the selection issue of multiple paths under an SR Policy, ensuring that the network can adapt to local conditions without overriding the controller's broader strategies.I'm not sure if I've explained everything clearly. If you have any further questions, please feel free to continue the discussion.

Best RegardsYisong 发件人: Joel Halpern时间: 2024/12/09(星期一)11:45收件人: Yisong Liu;spring;抄送人: draft-liu-spring-sr-policy-flexible-path-selection;主题: Re: [spring] Ask SPRING WG for review draft-liu-spring-sr-policy-flexible-path-selection

  
    
  
  
    Looking at this draft, there seem to be two related aspects, one
      of which makes sense, and one of which needs work.
    As a participant, I can understand the general goal.  And
      adjusting the path selection when component link issues reduce the
      overall available bandwidth, increase the end-to-end delay, or
      increase the expected jitter is understandable.  I leave whether
      this is the right approach to that problem to those who have
      worked more closely with SR policies.
    However, if I read section 4.1 properly, it wants to change the
      path selection in response to observed parameters such as observed
      packet loss (frequently in practice caused by congestion.)  On
      fortunately, distributed dynamic path selection based on
      parameters that are sensitive to traffic load has well-known
      problems with various responders adjusting resulting in simply
      moving the problem.  If you have recognized this problem and I
      missed it, please cite RFC 2386 early in the document, and point
      to the resolution.  If you have not addressed this problem, please
      either do so or restrict the applicability of this proposal. 
      Delaying response is not sufficient.
    
    Yours,
    Joel
    
    On 12/8/2024 9:37 PM, Yisong Liu wrote:
    
    
      
      
        Dear WG members,
        
        
        
            
        With
              the rise of AI models, new intelligent computing services
              require enhanced network reliability, especially in
              quality-sensitive scenarios like storage-compute
              separation and real-time inference. The
              draft-liu-spring-sr-policy-flexible-path-selection offers
              flexible path switching for quality degradation, crucial
              for maintaining network performance.
          
        
            
        
          This
                draft proposed a
                new mechanism to specify multiple candidate paths for SR
                policies, allowing for more sophisticated traffic
                engineering. It supports
                dynamic path adjustments based on real-time network
                conditions, optimizing resource utilization and ensuring
                high service quality. This draft aims to provide network
                operators with greater flexibility and control over
                traffic routing in SR networks.
          
              
          We
                have just posted a new version. Please see the draft in
                the following link:
          https://datatracker.ietf.org/doc/draft-liu-spring-sr-policy-flexible-path-selection/
        
        
          
        I
              hope you can review this draft and share your feedback.
              Welcome any questions and comments.
          
        
            
        Best Regards
        Yisong on behalf of co-authors
      
      
      
      
      _______________________________________________
spring mailing list -- [e-mail]
To unsubscribe send an email to [e-mail]