Hi, On 27.10.2016 17:23, David Miller wrote: > From: Jakub Sitnicki <j...@redhat.com> > Date: Mon, 24 Oct 2016 11:28:47 +0200 > >> However, for it to work IPv6 flow labels have to be same in both >> directions (i.e. reflected) or need to be chosen in a manner that >> ensures that the flow going in the opposite direction would actually >> be routed to a given path. > > My understanding is that this is not really guaranteed, and that > entities are nearly encouraged to set the flow label in whatever > manner makes sense for their use case.
In general this is true. > I think we really cannot have any kind of hard dependency on how > flow labels are set and used by the internet. Probably/Hopefully ECMP setups are set up by the same entity that also operates the servers, thus they can easily control the reflection of flow labels on those servers. This might be especially important for anycast services hosted behind ECMP services. If the flow labels don't match, these patches are just best effort and don't improve nor worsen the situation (lot's of traffic afaik still carries 0 as flow label which indeed does help). Bye, Hannes
