Hello, When using VXLAN over Internet connections, Openvswitch TCP performance is currently limited due to IP fragmentation: The Internet MTU is (at most) 1500 bytes, and the typical TCP MSS value of 1460 bytes used by clients becomes 1460+40+50 VXLAN = 1550 bytes.
The attached patch addresses this issue, by modifying the TCP MSS option in TCP SYN and SYN+ACK packets to account for VXLAN overhead. It only applies to packets sent to or from VXLAN ports ( though could be applied to other tunnel types as well ). I realize there are many things wrong about the patch, it's not properly formatted and we would want the feature to be configurable ( per port perhaps ). But before I go ahead and polish things up, I'd like to collect some feedback on the general approach and desirability of this feature. I built another patch to create a custom tcp-mss-rewrite Openflow action, but I think for many applications this would complicate things as flows have to be explicitly programmed. By making it part of the standard output action, it can simply be dropped in and existing applications can take advantage of the feature without modifications to their code Regards, Jeroen _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
