On 6/3/25 5:40 AM, 徐永軒 via discuss wrote: > Dear ovs-discuss, > > I'm encountering unexpected behavior with |GROUP type=SELECT| in Open vSwitch > and would appreciate your insights. > > According to the OpenFlow specification: > > Optional: select: Execute one bucket in the group. Packets are > processed > by a single bucket in the group, based on a switch-computed selection > algorithm > (e.g. hash on some user-configured tuple or simple round robin). All > configuration > and state for the selection algorithm is external to OpenFlow. > The selection algorithm should implement equal load sharing and can > optionally be based on bucket weights. When a port specified in a bucket in a > select group goes down, the switch /may/ restrict bucket selection to the > remaining > set (those with forwarding actions to live ports) instead of dropping packets > destined to that port. This behavior may reduce the disruption of a downed > link > or switch. > > However, in my test environment with 2 input and 2 output ports, I found that > if > one of the output ports goes down, traffic gets disrupted instead of > automatically > avoiding the down port. It seems like |SELECT| does not skip the downed port > and > continues sending traffic to it. > > > Is this the expected behavior for |SELECT| groups in OVS? Does Open vSwitch > support > dynamic port liveness detection and automatic exclusion of down ports in > |SELECT| > groups?
This part of the spec is optional and OVS doesn't implement it today. > If not, is there any workaround or configuration that enables this behavior? Workaround is for controller to monitor the port status (can be done through OpenFlow, I believe) and remove buckets that are referencing down ports. If your buckets consist of simple output actions, then you may try to replace the group with a balanced bond port with a NORMAL pipeline (actions:NORMAL) on the OVS bridge. Best regards, Ilya Maximets. _______________________________________________ discuss mailing list disc...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
