This is a proposal for remote checksum offload in VXLAN. We use a compressed format for the remote checksum offload data to support offload of UDP and TCP inner checksums. This allocates a reserved bit (#10 which would be immediately after version bits in VXLAN-GPE) and uses the 8 bits after VNI for data.
I have implemented this in Linux stack and posted a first cut on netdev (http://permalink.gmane.org/gmane.linux.network/339847). It works as expected, eliminating the need to perform host checksum computation over a packet when encapsulating TCP over VXLAN between hosts using plain NICs. In simple throughput tests this reduced CPU usage by ~20% on transmit, and using outer UDP checksum reduces CPU on receive by almost 50%. Comments are appreciated. Thanks, Tom ---------- Forwarded message ---------- From: <internet-dra...@ietf.org> Date: Tue, Dec 2, 2014 at 8:13 AM Subject: New Version Notification for draft-herbert-vxlan-rco-00.txt To: Tom Herbert <therb...@google.com> A new version of I-D, draft-herbert-vxlan-rco-00.txt has been successfully submitted by Tom Herbert and posted to the IETF repository. Name: draft-herbert-vxlan-rco Revision: 00 Title: Remote checksum offload for VXLAN Document date: 2014-12-01 Group: Individual Submission Pages: 6 URL: http://www.ietf.org/internet-drafts/draft-herbert-vxlan-rco-00.txt Status: https://datatracker.ietf.org/doc/draft-herbert-vxlan-rco/ Htmlized: http://tools.ietf.org/html/draft-herbert-vxlan-rco-00 Abstract: This specification describes remote checksum offload for VXLAN. Remote checksum offload is a mechanism that provides checksum offload of transport checksums in encapsulated packets using rudimentary offload capabilities found in most Network Interface Card (NIC) devices. The outer UDP checksum is enabled on transmit and, with some additional meta data, a receiver is able to deduce the checksum to be set in an encapsulated packet. Effectively this offloads the computation of the inner checksum which can be a significant performance optimization. Enabling the UDP checksum has the additional advantage that it covers more of the packet including the IP pseudo header and virtual network identifier. Please note that it may take a couple of minutes from the time of submission until the htmlized version and diff are available at tools.ietf.org. The IETF Secretariat _______________________________________________ nvo3 mailing list nvo3@ietf.org https://www.ietf.org/mailman/listinfo/nvo3
