Hi Erik, Thanks for pointing out. Yes, your understanding is correct. However, the issue might not be so serious considering that physical networks within data-center are usually highly reliable, which is the main usecase for this protocol.
Implementation can choose to make this feature configurable, and enable only under reliable environment. I will add this consideration into version 01. Best regards, Han On Mon, 2014-03-24 at 11:04 -0700, Erik Nordmark wrote: > On 3/14/14 8:52 PM, Zhou, Han wrote: > > > > Tom, the point of this draft is that the "last possible point in the > > stack" can > > be pushed to the remote end-point of the VXLAN tunnel. If the remote > > is an hypervisor, this GSO is terminated without actual work: the > > receiving hypervisor simply delivers the large packet to receiving guest. > Han, > > Are you saying that the sending VM and vswitch will send a large packet > (e.g., 32k) over UDP, and this will be delivered to the receiving > vSwitch and VM as one large packet? That certainly makes the work on the > VMs a lot less, hence I can understand that you see performance > improvements. > > However, that would result in IP fragmentation of that large UDP/VXLAN > packet AFAICT. > > The IETF has some experience with protocols where the loss unit is > smaller than the retransmission unit, and this results in very poor > performance under packet loss due to the loss of a single, small unit > resulting in the retransmission of a large unit (the 32k packet, which > might be a TCP, SCTP, etc packet i.e. a reliable protocol with > retransmissions.) > > Regards, > Erik > _______________________________________________ nvo3 mailing list [email protected] https://www.ietf.org/mailman/listinfo/nvo3
