Hi Ben/Team, I am working on implementation of eviction mechanism as per openflow specification 1.4 and thinking to contribute the same to openvswitch.
As per your previous inputs, the understanding of the feature is as follows: Eviction mechanism is already present in openvswitch on the basis of lifetime, configured by - ovs-vsctl create table command(defining overflow-policy as evict). With the implementation of eviction as per openflow specification 1.4, eviction should be set through table-mod messages. The command for the same would be like - "ovs-ofctl mod-table <bridge> <table> evict". Based on the above understanding, there are few points on which I need your inputs/suggestions: 1. Setting eviction using table-mod messages should not disturb the current ovs eviction configuration mechanism(without implementation of openflow specification 1.4). That means, if eviction is to be performed on the basis of lifetime only, then it should be configured via ovs-vsctl create table... command(overflow-policy evict) and if it is to be performed on the basis of importance only, then it should be configured via ovs-ofctl mod-table... command ? 2. As per the openflow specs 1.4, section 7.3.4.1 (Page 72) "The OFPTMPT_EVICTION property usually cannot be modified using a OFP_TABLE_MOD request, because the eviction mechanism is switch defined, and this property is usually only used in a OFPMP_TABLE_DESC multipart reply to inform the controller about the eviction mechanism used." By this, does it imply that if eviction for lifetime is set by ovs-vsctl create command, then the table property cannot be modified for eviction via importance using ovs-ofctl mod-table command. That is for a given table, eviction can be configured only once either via lifetime(ovs-vsctl create..) or importance (by table-mod messages...)? It will be great help if you can reply to our queries asap. Thanks in advance for the help. Thanks and Regards, Saloni Jain Tata Consultancy Services Mailto: saloni.j...@tcs.com Website: http://www.tcs.com ____________________________________________ Experience certainty. IT Services Business Solutions Consulting ____________________________________________ Proud title sponsor of the TCS New York City Marathon -----Ben Pfaff <b...@nicira.com> wrote: ----- To: Saloni Jain <saloni.j...@tcs.com> From: Ben Pfaff <b...@nicira.com> Date: 08/22/2014 08:54PM Cc: dev@openvswitch.org, Hiteshi Madan <hiteshi.ma...@tcs.com>, Deepankar Gupta <deepankar.gu...@tcs.com> Subject: Re: [ovs-dev] Openflow 1.4: Eviction mechanism implementation On Fri, Aug 22, 2014 at 05:17:32PM +0530, Saloni Jain wrote: > Kindly validate following approach for implementation of eviction > mechanism and vacancy events as specified in openflow specification > 1.4. According to specification eviction and vacancy events are set > through table_mod messages. > > Based on this scenerio, there are two cases: > > CASE 1: When both Eviction and Vacancy Events are set. > When the remaining space in flow table decreases to vacancy_down, a vacancy > down event is generated and sent to the controller. > This will start Eviction mechanism on the switch. > Eviction will be performed on the basis of "importance" or "lifetime" or > both. If "importance" flag is the only flag set, flow entry with less > importance will be deleted and comparison is done between the current vacancy > and vacancy_up value. I don't understand this linkage between vacancy and eviction. I understand eviction to occur when a flow table is full. Can you point out the OpenFlow specification text that says that eviction should occur based on configured vacancy? OVS already has a configurable eviction policy. This should be part of the mechanism. =====-----=====-----===== Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
