On Tue, Mar 14, 2017 at 1:25 PM, Stephen Hemminger <step...@networkplumber.org> wrote: > On Tue, 14 Mar 2017 11:48:37 -0700 (PDT) > David Miller <da...@davemloft.net> wrote: > >> From: Nikolay Aleksandrov <niko...@cumulusnetworks.com> >> Date: Tue, 14 Mar 2017 17:58:46 +0200 >> >> > On 14/03/17 17:55, Stephen Hemminger wrote: >> >> On Tue, 14 Mar 2017 17:36:15 +0200 >> >> Nikolay Aleksandrov <niko...@cumulusnetworks.com> wrote: >> >> >> >>> This patch adds support for ECMP hash policy choice via a new sysctl >> >>> called fib_multipath_hash_policy and also adds support for L4 hashes. >> >>> The current values for fib_multipath_hash_policy are: >> >>> 0 - layer 3 (default) >> >>> 1 - layer 4 >> >>> If there's an skb hash already set and it matches the chosen policy then >> >>> it >> >>> will be used instead of being calculated (currently only for L4). >> >>> In L3 mode we always calculate the hash due to the ICMP error special >> >>> case, the flow dissector's field consistentification should handle the >> >>> address order thus we can remove the address reversals. >> >>> >> >>> Signed-off-by: Nikolay Aleksandrov <niko...@cumulusnetworks.com> >> >> >> >> It is good to see ECMP come back from the grave. >> >> Linux used to support it long ago but was abandoned after it was unstable >> >> and removed from iproute2 in 2012. >> >> >> >> The old API was through route attributes which makes more sense than >> >> doing it with sysctl. It makes more sense to use netlink instead. >> >> Therefore please go back and do something like the old API rather than >> >> doing it through >> >> sysctl. >> >> >> > >> > That's what my initial version did, but this was discussed during NetConf >> > in Seville >> > and it was decided that it's best to make a global sysctl, thus the change. >> >> Correct, we discussed this, and we all agreed to only have a sysctl for now. > > Why? If you are going to have private discussions please post the rationale > in public.
Stephen, is there any reason to have a per ecmp route multipath algo selection ?. All platforms have a global multipath selection algo. I also don't see routing daemons ready or willing to specify a per ecmp route multipath selection algo attribute.
