- <p>
- GRE checksums impose a significant performance penalty because they
- cover the entire packet. The encapsulated L3, L4, and L7 packet
- contents typically have their own checksums, so this additional
- checksum only adds value for the GRE and encapsulated L2 headers.
+ <p>
+ When using the upstream Linux kernel module, computation of
+ checksums for <code>geneve</code> and <code>vxlan</code> requires
+ Linux kernel version 4.0 or higher. <code>gre</code> supports
+ checksums for all versions of Open vSwitch that support GRE.
+ The out of tree kernel module distributed as part of OVS
+ can compute all tunnel checksums on any kernel version that it
+ is compatible with.