Re: [mif-arch-dt] New Version Notification for draft-anipko-mif-mpvd-arch-00.txt

[Tim Chown <[e-mail]>]

Hi,

Some quick comments, as I won't now be able to make the call today.

Overall, the draft is taking shape nicely.

Section 1

If we talk of common scenarios, should we list them? Should we pick a couple that can be drilled into as examples later in the document, or in an Appendix? We had some discussion on this previously in the calls, but did we agree, what if anything, should go in this text?

Section 2.1 

This explains how the PVD architecture can be incrementally deployed, with incremental benefit, which is a nice property - perhaps the title of that section can be tweaked, or the topic of implicit vs explicit PVD discovery separated?

Towards the end of section 2.1 it would be great to have heuristics to do better than putting all implicit PVD information into one bucket, e.g. where a host is multihomed, where in such a case the host would have some idea of this due to multiple global prefixes.

Section 2.3

Are PVD IDs unique per PVD, per association between the client and PVD, per location, or…? e.g. if I am with a WiFi provider, will I always see the same PVD when I use that provider, anywhere? Would a friend on that provider see the same ID? Can any assumptions be made? As yet I don't think this is stated.

Section 2.4

The single PVD for dual-stack networks seems very sane. It is common today for a dual-stack host to get an IPv6 address and router via IPv6 RA, and other configuration information via IPv4 DHCP.

Section 4.2

So if there is an explicit vs implicit distinction for learning PVDs, perhaps a similar model should be applied here, explicit being e.g. a user toggle (explicit choice, rather like 3G vs WiFi, as hinted at in section 2.3), the implicit being e.g. connectivity tests (Happy PVDs?).

Section 4.2.1

A host may pick multiple PVDs intentionally to use MPTCP; it may explicitly want to ensure it is using different channels per path.

There may be cases for split PVDs, e.g. a host with VPN running, uses the VPN to the corporate network and the default provision for all other traffic (cue security comments…).

Section 5.1

Perhaps in addition to connection requests by applications the applications will first do DNS lookups, which is where the PVD selection is first used?

Section 6

eduroam is an interesting example here. Users authenticate to their home site using their home credentials, but the visited site then makes a provisioning (and authorisation) decision based on that result.  The visited site is the PVD, but the authentication is to the home site.  The authentication to eduroam can be mutual between the device and the visited network.

And a final question for now - are we including application configuration in this work, or is it purely network services?

Tim