Welcome, have fun researching. Ethan
On Fri, Apr 6, 2012 at 13:09, 陳泰達 <folay...@gmail.com> wrote: > I used to be an expert of TCP (well, in college), but I've forgotten lots > things > about it, LoL.... But I am sure that the SACK TCP can handle the out of > order > issue. It will work more "smoothly" if the packets arrive in order though. > But the overall throughput of "SACK TCP with LACP" is unknown for me. > Maybe it's an interesting issue for researchers. I will survey the related > documents about it. And thank you, you inspire me a lot!! > > > 2012/4/7 Ethan Jackson <et...@nicira.com> >> >> Please keep replies on the list. >> >> > That's a good point for why a TCP flow cannot be distributed >> > to different links simultaneously. Thanks a lot. >> > But the TCP SACK mode can handle the out of order issue, isn't it? >> >> I'm not a tcp expert. My understanding is that out of order packets >> typically cause tcp backoffs. I may be wrong on this point, but in >> general networking equipment tries to deliver packets in order for >> this reason. Even if tcp can handle it gracefully, a bonding >> implementation that consistently delivers packets out of order is >> incorrect. >> >> Ethan >> >> >> > >> > 2012/4/7 Ethan Jackson <et...@nicira.com> >> >> >> >> >> OVS can't distribute packets of the same flow to different >> >> >> interfaces. >> >> >> >> As far as I know, this is typical of all bonding implementations. If >> >> you send packets from the same flow down different links, they may >> >> arrive at the destination out of order. This can wreak havoc on tcp >> >> stacks. >> >> >> >> >> OVS can't really achieve balance/fairness between flows. >> >> >> OVS can't dynamically switch a flow between different interfaces on >> >> >> the >> >> >> fly based on the bandwidth utilization. >> >> >> >> This isn't true, if one slave is receiving quite a bit more traffic >> >> than another, some flows will be rebalanced to the less loaded one. >> >> By default this is done once every 10 seconds, but that's >> >> configurable. >> >> >> >> >> So it means the LACP implemented in OVS is not mature? >> >> >> Or it's just the nature of LACP? It needs extra QoS scheme to >> >> >> achieve >> >> >> real balance and full bandwidth utilization? >> >> >> >> This is just the nature of bonding implementations. >> >> >> >> Ethan >> >> _______________________________________________ >> >> discuss mailing list >> >> discuss@openvswitch.org >> >> http://openvswitch.org/mailman/listinfo/discuss >> > >> > > > _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
