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SV2022's avatar
SV2022
Icon for Cirrus rankCirrus
May 24, 2024
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Stateless VS

hi,

 

i dont see out packets count increasing under statistics for stateless VS (UDP)

is this expected behaviour?

 

f5
LTM
udp
  • F5_Design_Engineer's avatar
    F5_Design_Engineer
    May 26, 2024

    Hi SV2022,

     

     

    With UDP Datagram LB set to Enabled, if you also set the Timeout to Immediate, UDP response traffic is forwarded to the client using the origin server's source IP address and port. As a result, response traffic may not appear to have originated from the virtual server to which the request was sent, and traffic disruption may occur when a client and/or routing expects the UDP source IP address to be the address other than the origin server. You can avoid this issue by setting the timeout to a value other than Immediate whenever possible.

     

    The Idle Timeout value of "Immediate" will result in every connection being immediately flagged for removal (i.e. timeout of 0 seconds).

    K13675 describes the Stateless UDP Virtual Server which is connectionless but has some limitations.
    K3605 describes altering the datagram lb value in the UDP profile so that UDP datagrams are load balanced individually rather than per connection. Note that like setting Idle Time to immediate, more load balancing decisions means more CPU consumption.

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  • F5_Design_Engineer's avatar
    F5_Design_Engineer
    Icon for MVP rankMVP
    May 26, 2024

    Hi SV2022,

     

     

    With UDP Datagram LB set to Enabled, if you also set the Timeout to Immediate, UDP response traffic is forwarded to the client using the origin server's source IP address and port. As a result, response traffic may not appear to have originated from the virtual server to which the request was sent, and traffic disruption may occur when a client and/or routing expects the UDP source IP address to be the address other than the origin server. You can avoid this issue by setting the timeout to a value other than Immediate whenever possible.

     

    The Idle Timeout value of "Immediate" will result in every connection being immediately flagged for removal (i.e. timeout of 0 seconds).

    K13675 describes the Stateless UDP Virtual Server which is connectionless but has some limitations.
    K3605 describes altering the datagram lb value in the UDP profile so that UDP datagrams are load balanced individually rather than per connection. Note that like setting Idle Time to immediate, more load balancing decisions means more CPU consumption.