Brian E Carpenter wrote:
Jason, I understand your goal here and it is very reasonable. However, I would like to ask whether this policy-like information should be signalled in-band with the locator set (which is host to host) or whether it should be signalled out of band as a policy mechanism, and in that case signalled site to site. I'm assuming that the real requirement is to apply site to site preferences.
I'm not Jason but ...I'm not sure the big picture is in scope for the WG, but it makes sense to think about the big picture a bit, and whether there is need/utility in a shim6 piece.
For sites that have significant traffic concentration (e.g., www.examle.com being involved in 99% of the traffic for the example.com site), then I can see how the combination of SRV records (with priority and weight) and some similar mechanism in the shim6 control protocol can provide significant control of the traffic. But it requires that the priority/weight be configured not only in the DNS server but also be fed to the shim on the host.
Even for a site with less traffic concentration to one or a few hosts, this would be beneficial. But one would need to manually configure each of the hosts with the priority/weight type things.
- Perhaps automating this configuration (DHCP?) would be worth-while? - Perhaps source address selection should take the priority/weight type thing into account so that outgoing connections follow the intent of the policy?None of this imply that the policy need to be load dependent, thus I think we can avoid Spencer's concern about oscillation (that are valid concerns any time the path selection is a function of some measured characteristic.)
Erik