On Thu, Feb 15, 2018 at 12:56 AM, David Ahern <dsah...@gmail.com> wrote: > On 2/14/18 3:45 PM, Or Gerlitz wrote:
>> how the various systems you are dealing with do with traffic that involves >> ipv6 extension headers? what about environments with GRE? in ipv4 GRE >> fabrics are just broken for ECMP, in ipv6 they can fly with flow label but >> will crash again with L4 hash. > If you like your ecmp hash algorithm, you can keep your ecmp hash algorithm. > This gives users a choice; it is not a requirement to move from L3 only > to L4. Further, this makes IPv6 on par with IPv4 with a choice between > L3 and L4 and allows users to decide what works best for them. Looking in the code for tunnels e.g in the vxlan xmit path (but I believe this is the case for other UDP tunnels as well), a call is made to generate the source udp port as the hash of the overlay tuple regardless if we are on v4/v6. Next, when it comes to ipv6, the kernel computes the flow label which effectively takes into account the inner header.
