WPD - Proxy Discovery

Hi everyone. Staying with WPD, I too have some additional input to the WPD draft.

I believe, WPD assumes, or even requires, that the initial WPD authority is explicitly configured somehow*.  That configuration implies that authorization occurs prior to any discovery.  Discovery is pretty much limited to finding a valid instance. [*For this email, assuming that this can happen as a result of a direct user action; or it could be baked into the client somehow. From the outside, these are basically indistinguishable]

I have a suggestion. How about, have the network advertise the availability of proxies? This would invert the order of operations, so that an advertisement could be made, the client would acquire the WPD and a user would - if they choose to use a proxy at all - be able to select from the list of advertised proxies.

Automatic discovery of proxies presents some challenges.  Of all of the discovery mechanisms the IETF has produced (and the multitude proposed outside of the IETF), there isn't a single one that is universally applicable.  Most of these mechanisms rely on layer 2 features, where the only common layer on the Internet is layer 3.

Would like to hear if anyone has any thoughts on this.

Thanks
Sanjay