OPAF users have reported an issue where the reference GDS does not support RegisterServer() and RegisterServer2(). Randy said that this is by design. Servers are expected to register with an LDS and LDSes can be chained and aggregated by a GDS, so Servers never register directly with a GDS hence RegisterServer2 and RegisterServer are not supported by a GDS.

Randy explained in the degenerate case where embedded Servers are acting as their own LDS, they should register with a single remote LDS running on the same node as the GDS and the GDS would then aggregate the local LDS and hence get all of the Server registration information. Unfortunately, our reference GDS implementation does not listen for nDNS and has no other way to be manually configured to aggregate the local LDS so at present OPAF can not make this work. Also, in practice the GDS should manage the trust list of the local LDS to control what Servers are allowed to register with it.

We discussed the merits of fixing our implementation by simply having the GDS act also as the LDS (by implementing RegisterServer and RegisterServer2) or by sticking with the layered architecture and modifying the reference GDS to work properly with the local LDS. We believe we can clarify in the specs how this should work from a UA Application point of view whereby the paired GDS/LDS combo versus a single GDS providing both LDS and GDS functionality is an implementation detail that is transparent to the users (i.e. GDS implementers could choose either modularity and would be compliant).