So your goal is to just use OVS to modify packet headers and do everything else with a separate switch? OVS should be able to do that, with appropriate OpenFlow rules. There's no reason that the packets would have to have a particular Ethernet destination address.
On Sun, Jun 26, 2011 at 03:53:41PM -0400, Aaron Rosen wrote: > If I just outputted these packets to the port that that OVS box is > running on would that work? Or would the DL_DST address of the packet > need to match that of the OVS box? > > On Sun, Jun 26, 2011 at 3:21 PM, Ben Pfaff <b...@nicira.com> wrote: > > Yes, the PC running OVS would have to be used as a switch. If one of > > your requirements is that you need more than the number of Ethernet > > ports you can conveniently put in a PC chassis (which is often 6 to 10 > > ports), then it's not a good way to go. > > > > Presumably the hardware switch's performance drops because the ASIC > > can't do what you are asking and every packet has to be sent to the > > switch CPU. Switch CPUs are usually quite slow and often the channel > > from ASIC to CPU is ratelimited too. With OVS, every packet already > > goes up to the CPU (that's a NIC's job after all) and there's very > > little incremental cost to modifying a few headers. > > > > On Sun, Jun 26, 2011 at 03:15:48PM -0400, Aaron Rosen wrote: > >> But in order to use OVS in this manor I would need a box running OVS > >> that everyone first sent their traffic to first right? Is the reason > >> why OVS can perform a factor of 1000 faster is because the > >> implementation is better or because the hardware of a commodity PC is > >> better for this than that of the OF switch that is doing the > >> modifying? Just curious. > >> > >> On Sun, Jun 26, 2011 at 3:00 PM, Ben Pfaff <b...@nicira.com> wrote: > >> > On Sun, Jun 26, 2011 at 02:54:13PM -0400, Aaron Rosen wrote: > >> >> Thanks for your reply. I just tested this on the same HP just > >> >> rewriting the DL_DST and the performance is the same there too so it > >> >> must be done in software completely on these switches :( > >> > > >> > You mentioned a "high" rate of 683 Mbit/sec. If that's a good rate for > >> > you, you don't need switching ASIC for that. Open vSwitch can handle > >> > several gigabits per second on commodity PC server hardware. And its > >> > performance won't drop by a factor of 1000 when you start modifying > >> > headers. _______________________________________________ openflow-discuss mailing list openflow-discuss@lists.stanford.edu https://mailman.stanford.edu/mailman/listinfo/openflow-discuss
