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Hi Bernard,

Networking-sfc currently uses OF1.3. Although OF1.3 dumps all groups, networking-sfc has follow-on filter code to select the info associated with the specific group ID from the dump. So we are fine and let's keep it as OF1.3. 

We can upgrade to OF1.5 when Neutron uses OF1.5. 

Thanks,
Cathy


-----Original Message-----
From: Bernard Cafarelli [mailto:bcafarel at redhat.com] 
Sent: Tuesday, September 20, 2016 7:16 AM
To: OpenStack Development Mailing List
Subject: [openstack-dev] [networking-sfc] OpenFlow version to use in the OVS agent

In the OVSSfcAgent migration to a L2 agent extension review[1], Igor Duarte Cardoso noticed a difference on the OpenFlow versions between a comment and actual code.
In current code [2], we have:
# We need to dump-groups according to group Id, # which is a feature of OpenFlow1.5 full_args = ["ovs-ofctl", "-O openflow13", cmd, self.br_name

Indeed, only OpenFlow 1.5 and later support dumping a specific group [3]. Earlier versions of OpenFlow always dump all groups.
So current code will return all groups:
$ sudo ovs-ofctl -O OpenFlow13 dump-groups br-int 1 OFPST_GROUP_DESC reply (OF1.3) (xid=0x2):
 group_id=1,type=select,bucket=actions=set_field:fa:16:3e:05:46:69->eth_dst,resubmit(,5),bucket=actions=set_field:fa:16:3e:cd:b7:7e->eth_dst,resubmit(,5)
 group_id=2,type=select,bucket=actions=set_field:fa:16:3e:2d:f3:28->eth_dst,resubmit(,5)
$ sudo ovs-ofctl -O OpenFlow15 dump-groups br-int 1 OFPST_GROUP_DESC reply (OF1.5) (xid=0x2):
 group_id=1,type=select,bucket=bucket_id:0,actions=set_field:fa:16:3e:05:46:69->eth_dst,resubmit(,5),bucket=bucket_id:1,actions=set_field:fa:16:3e:cd:b7:7e->eth_dst,resubmit(,5)

This code behavior will not change in my extension rewrite, so this will still have to be fixed. though I am not sure on the solution:
* We can use Openflow 1.5, but its support looks experimental? And Neutron apparently only uses up to 1.4 (for OVS firewall extension)
* Method to dump a group can "grep" the group ID in the complete dump.
Not as efficient but works with OpenFlow 1.1+
* Use another system to load balance across the port pairs?

Thoughts?
In gerrit, I kept it set to 1.5 (no impact for now as this is still marked as WIP)

[1]: https://review.openstack.org/#/c/351789
[2]: https://github.com/openstack/networking-sfc/blob/master/networking_sfc/services/sfc/common/ovs_ext_lib.py
[3]: http://openvswitch.org/support/dist-docs/ovs-ofctl.8.txt

--
Bernard Cafarelli

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