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    TNSR ECMP Algorithms?

    Scheduled Pinned Locked Moved TNSR
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    • C
      cmooney
      last edited by

      Hi,

      We are considering TNSR for an upcoming project.

      Part of the requirements we have is to perform ECMP across a number of devices, but only hash on the source ip of each packet. I.e. we have a requirement that all traffic from source IP A always be sent to R1 on the other side.

      I know Linux out of the box cannot do this, its two configurable ECMP modes are 'L3' (which use SRC+DST IP) and 'L4' (which uses SRC IP + DST IP + SRC PORT + DST PORT + PROTOCOL.)

      I know certain vendor implementations allow selection of only Source IP for ECMP. Can anyone advise if this is possible with VPP / TNSR?

      Thanks.

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      • dennis_sD
        dennis_s
        last edited by

        Hi @cmooney,

        I am not sure it would work like that, we would let routing protocol decide on the best path(s) to take. However, to see if this is something that is configurable I would contact one of our sales engineers to see if it's possible.

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        • C
          cmooney
          last edited by

          It's not really to do with the routing protocol, it's really about the underlying packet forwarding engine.

          I can add two equal cost routes by creating two statics to different destinations, or those two equal-cost routes can be from OSPF, BGP etc. etc.

          The question is once there are two equal routes in the table how does the platform load-share between the two different next-hops.

          Thanks.

          dennis_sD 1 Reply Last reply Reply Quote 0
          • dennis_sD
            dennis_s @cmooney
            last edited by

            That is done via round-robin.

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            • C
              cmooney
              last edited by

              How do you mean round-robin?

              Per-packet round robin?

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              • fractal_boyF
                fractal_boy
                last edited by

                more details on ECMP are here https://fdio-vpp.readthedocs.io/en/latest/gettingstarted/developers/fib20/dataplane.html

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                • R
                  razysej
                  last edited by fractal_boy

                  Balances traffic based on source IP, destination IP, source port, destination port, and protocol, allowing effective load distribution while maintaining session consistency.

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                  • A
                    ameliataylor
                    last edited by

                    This post is deleted!
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