No one with whom to negotiate transport selection

[paulehoffman]

In section 5.2, point 3 ends with:

... then a recursive server SHOULD negotiate selection of an available transport protocol.

However, there is no negotiation happening at all: the resolver just picks an available transport based on its configuration. This whole point can be replaced with something saying that the resolver should have some configuration to deal with authoritative servers that have multiple transports available.