On Tue, Aug 30, 2016 at 12:17:06PM +1200, Warsang wrote: > On 08/29/16 17:29, Ben Pfaff wrote: > >On Mon, Aug 29, 2016 at 07:22:10PM +1200, Warsang wrote: > >>Hello, > >> > >>I was wondering how the bucket selection is made in OVS 2.4 I found this in > >>the ml archive > >>http://openvswitch.org/pipermail/discuss/2016-January/019984.html > >>saying that :" > >> > >>Open vSwitch 2.4 and later by default hashes the source and > >> destination Ethernet address, VLAN ID, Ethernet type, IPv4/v6 > >> source and destination address and protocol, and for TCP and SCTP > >> only, the source and destination ports. The hash is "symmetric", > >> meaning that exchanging source and destination addresses does not > >> change the bucket selection. > >That information is correct. It comes from the OVS FAQ. The entire FAQ > >entry says: > > > >### Q: How does OVS divide flows among buckets in an OpenFlow "select" group? > > > >A: In Open vSwitch 2.3 and earlier, Open vSwitch used the destination > > Ethernet address to choose a bucket in a select group. > > > > Open vSwitch 2.4 and later by default hashes the source and > > destination Ethernet address, VLAN ID, Ethernet type, IPv4/v6 > > source and destination address and protocol, and for TCP and SCTP > > only, the source and destination ports. The hash is "symmetric", > > meaning that exchanging source and destination addresses does not > > change the bucket selection. > > > > Select groups in Open vSwitch 2.4 and later can be configured to > > use a different hash function, using a Netronome extension to the > > OpenFlow 1.5+ group_mod message. For more information, see > > Documentation/group-selection-method-property.txt in the Open > > vSwitch source tree. (OpenFlow 1.5 support in Open vSwitch is still > > experimental.) > Thank you for your answer > >>I am trying to implement ECMP in ryu controller so if I do understand > >>correctly, using buckets from SELECT group is not the correct solution for > >>it uses a very different selection method is that right? > >What kind of selection method do you want? > I was thinking of using the ECMP five-tuple (Ip src, Ip dst, protocol, L4 > src port, L4 dst port) through a hash (CRC16 or MD5) modulo 100,and then > depending on the value of the hash, sending it to a corresponding bucket. Or > am I missunderstanding something in how ECMP works?
The default OVS hash includes all of those fields. _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
