C2MS11 — Requesting data via pub/sub requires knowing publisher's service name

Requesting data, such as telemetry, via pub/sub requires knowing the publisher's server name. There should be a way to request data without this being already known. This could potentially be solved by a registry concept, as in C2MS11-1, but this particular issue proposes adding a service-matching capability wherein the requester is asking for a subscription to some data and the request results in linking the subscription to a service that provides that data.