Hi Ben No doubt you are a legend but you are wrong in this question or I'm totally screwed :)
I think you did not understand the question correctly. OvS has a buffer mechanism for each controller. While trying to add a flow_mod with max_length is not OFPCML_NO_BUFFER, the packets are stored in the buffer. If the maximum capacity is exceeded, OvS start sending the whole packets instead of related parts in the packet-in messages. Finally, its size (PKTBUF_CNT) is 512. @Majid, just set max-lenght (different than 0xFFFF) and then drop the packet-in messages in the controller and then you'll see the whole packets after 512th packet-in. - Volkan ________________________________________ From: discuss [discuss-boun...@openvswitch.org] on behalf of Ben Pfaff [b...@ovn.org] Sent: Thursday, April 14, 2016 6:56 PM To: Majid Taleqani Cc: discuss@openvswitch.org Subject: Re: [ovs-discuss] open vSwitch port input buffer capacity On Thu, Apr 14, 2016 at 01:52:31PM +0000, Majid Taleqani wrote: > i am writing a DDOS mitigation for openflow networks using pox > controller and open vSwitch version 1.9. as DDOS attacks aim at > Flooding flow tables and input buffers, i wonder what is the maximum > capacity of each switch port input buffer. OVS ports themselves don't have buffers, so this is a question of your NIC driver's buffering strategy. > i know after the switch input buffer overflows then the switch sends > the whole packet to the controller No, that's wrong. Buffer overflow has nothing to do with sending packets to the controller. > and then the controller responses by sending packet out message which > contains the whole packet and also the action. i want to know how > much data and at what rate should a host send data to overflow a > switch port input buffer and if is it possible to change the switch > port input buffers? is it possible to change the amount of time that a > packet stays in buffer before timeouts? thanks _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
