Re: [PATCH net-next] ipv6: Move ipv6 stubs to a separate header file

[Alexei Starovoitov <alexei.starovoitov@gmail.com>]

On Sun, Mar 24, 2019 at 06:56:42AM -0600, David Ahern wrote:
> 
> This change also enables many other key features:
> 1. IPv4 multipath routes are not evicted just because 1 hop goes down.
> 2. IPv6 multipath routes with device only nexthops (e.g., tunnels).
> 3. IPv6 nexthop with IPv4 route (aka, RFC 5549) which enables a more
> natural BGP unnumbered.
> 4. Lower memory consumption for IPv6 FIB entries which has no sharing at
> all like IPv4 does.
> 5. Allows atomic update of nexthop definitions with a single replace
> command as opposed to replacing the N-routes using it.

Does kernel work as data plane or control plane in any of the above
features ?
Sadly the patches allow it to do both, but cumulus doesn't use it
for data path. The kernel on control plane cpu is merely a database.
And today it doesn't scale when used as a database.
The kernel has to be fast as a dataplane but these extra features
will slow down the routing by making kernel-as-database scale a bit better.
Hence my suggestion in the previous email: use proper database
to store routes, nexthops and whatever else necessary to program the asic.
The kernel doesn't need to hold this information.