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.
