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[Rodolfo Alonso <1952770@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

The "--strict" parameter during the OF deletion was introduced to be
able to define the parameter "priority" in the flow filter. Without "--
strict" is not possible to filter by "priority". E.g.:

[root@compute-0 ~]# ovs-ofctl del-flows br-int priority=100,table=60,in_port=144  # error                                                                                                                                                                    
ovs-ofctl: unknown keyword priority
[root@compute-0 ~]# ovs-ofctl del-flows --strict br-int priority=100,table=60,in_port=144  # ok


With deferred OF application (that means all flows are written/deleted at the same time, at the end of the deferred context), these strict flow deletion commands are executed before anything else. In some cases we have seen this small window can affect to some kind of traffic. For example UDP traffic is disrupted, the UDP packets arrive to the destination disordered. That could affect some applications.

Further considerations: with trunk ports, as printed in [1], we can see
that each subport has its own port ID (for rules with priority 100) and
each own VLAN+MAC (for rules with priority 90).

[1]https://paste.opendev.org/show/811353/

** Affects: neutron
     Importance: Undecided
     Assignee: Rodolfo Alonso (rodolfo-alonso-hernandez)
         Status: New

** Changed in: neutron
     Assignee: (unassigned) => Rodolfo Alonso (rodolfo-alonso-hernandez)

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https://bugs.launchpad.net/bugs/1952770

Title:
  [OVS][FW] Do not delete flows with "--strict" parameter in the OVS FW

Status in neutron:
  New

Bug description:
  The "--strict" parameter during the OF deletion was introduced to be
  able to define the parameter "priority" in the flow filter. Without "
  --strict" is not possible to filter by "priority". E.g.:

  [root@compute-0 ~]# ovs-ofctl del-flows br-int priority=100,table=60,in_port=144  # error                                                                                                                                                                    
  ovs-ofctl: unknown keyword priority
  [root@compute-0 ~]# ovs-ofctl del-flows --strict br-int priority=100,table=60,in_port=144  # ok

  
  With deferred OF application (that means all flows are written/deleted at the same time, at the end of the deferred context), these strict flow deletion commands are executed before anything else. In some cases we have seen this small window can affect to some kind of traffic. For example UDP traffic is disrupted, the UDP packets arrive to the destination disordered. That could affect some applications.

  Further considerations: with trunk ports, as printed in [1], we can
  see that each subport has its own port ID (for rules with priority
  100) and each own VLAN+MAC (for rules with priority 90).

  [1]https://paste.opendev.org/show/811353/

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