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Amanpreet_Singh's avatar
Amanpreet_Singh
Icon for Cirrostratus rankCirrostratus
Aug 19, 2016

dest_addr with Standard VS type

Hi Geeks,

 

I have seen a VS:80 setup on LTM with 'Standard' type,only "TCP Profile", "Pool", "SNAT pool" and "dest_addr" Destination address affinity.

 

I was in impression that dest_addr is used when either there VS is working as Caching or its a Wild card VS, so that LTM will look at the destination address in packet and create a persistence record so that next time the same destination will use the previous resource.

 

But the setup I see contradict my understanding. How would LTM be able to determine Destination address in "Standard VS Type" because of the fact that Destination address in the packets coming in from clients always has VS address.

 

Please help!

 

Regards, Aman

 

12 Replies

  • Destination address will always be sent to the same pool member, if available. AKA, it isn't load balanced in your scenario.

     

    • Amanpreet_Singh's avatar
      Amanpreet_Singh
      Icon for Cirrostratus rankCirrostratus

      Hi,

       

      My question is can we use dest_addr with standard virtual server type with 2 web servers as pool member?

       

    • ekaleido's avatar
      ekaleido
      Icon for Cirrus rankCirrus

      Yes you can, but you won't be load balancing. Traffic will always go to one node, as long as the node is available.

       

    • Amanpreet_Singh's avatar
      Amanpreet_Singh
      Icon for Cirrostratus rankCirrostratus

      Hi

       

      If the load balancing will not happen, how VS will deciede which pool member to select to new connection? Since the destination address in client request will only contain the VS IP

       

  • Destination address will always be sent to the same pool member, if available. AKA, it isn't load balanced in your scenario.

     

    • Amanpreet_Singh's avatar
      Amanpreet_Singh
      Icon for Cirrostratus rankCirrostratus

      Hi,

       

      My question is can we use dest_addr with standard virtual server type with 2 web servers as pool member?

       

    • ekaleido_26616's avatar
      ekaleido_26616
      Icon for Cirrocumulus rankCirrocumulus

      Yes you can, but you won't be load balancing. Traffic will always go to one node, as long as the node is available.

       

    • Amanpreet_Singh's avatar
      Amanpreet_Singh
      Icon for Cirrostratus rankCirrostratus

      Hi

       

      If the load balancing will not happen, how VS will deciede which pool member to select to new connection? Since the destination address in client request will only contain the VS IP

       

  • Note that there is also a port specific wildcard server, so a VS with a network destination and specific port like 10.10.10.10/24:80 could still make use of dest_addr persistence.

     

    Using dest_addr persistence on a VS that only has one address as a destination wouldn't make much sense.