Ben, Thanks for the response. Have few follow-up questions, am using ovs 2.5.
1) "group_best_live_bucket()" function - Is this function traversed in control path everytime when the data path flows inside kernel expire? 2) In this method, if a new bucket is added with higher weight, there is a good chance that its score could be high? Which means ovs does not use consistent hashing and does not guarantee stickiness for a given connection? 3) Or does ovs remembers the map of a flow to a live bucket to guarantee stickiness? Couldnt find, please point if such is the case. Stickiness would aid stateful applications. 4) Also, when using "output:1" - 1(tun-patch-port), does not work in actions in a bucket. In such case datapath rule with action=drop is getting programmed. But the same works if action=NORMAL is used. Does this mean <output:port> action cannot be used inside group table? Thanks & Regards, Ahmed khan On Mon, Apr 24, 2017 at 9:36 PM, Ben Pfaff <[email protected]> wrote: > No, select buckets don't use mod-n to select a bucket. Instead, for > each live bucket, OVS hashes flow data with the bucket ID and multiplies > by the bucket weight to obtain a "score", and then selects the bucket > with the highest score. > > On Mon, Apr 24, 2017 at 12:27:16AM +0530, Ahmed Khan wrote: > > Hi ben, > > Let me rephrase. > > > > Does hashing involve mod on number of buckets in a group ? If a new > bucket > > is added/deleted in a group, would it result in different hash value and > > hence a selection of different bucket for the same 5 tuple ? > > > > Also, how many buckets per group does ovs support ? And how many group > > tables are supported ? > > > > Thanks. > > > > On 22 Apr 2017 02:34, "Ben Pfaff" <[email protected]> wrote: > > > > > On Thu, Apr 20, 2017 at 04:12:20PM +0530, Ahmed Khan wrote: > > > > I understand 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.* > > > > > > > > *"""* > > > > > > > > *How does bucket size impact selection ? If entries are added/deleted > > > > to/from bucket, then for the same 5tuple is it rehashed and new entry > > > > could get selected ?* > > > > > > OpenFlow groups do contain buckets, but buckets do not have entries. > > > Therefore, entries cannot be added or deleted within buckets, so I > don't > > > understand the question. Can you rephrase it? > > > > > > Thanks, > > > > > > Ben. > > > > -- Success happens when people work energetically and avoid burn out.
_______________________________________________ discuss mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
