Link to definition of required RPC calls

[retog]

The README lists the RPC Procedures that an implementation needs to implement to be testable in netsim.

All but one of these procedures are not mentioned in the linked SSB Protocol Guide.

It would be good to link to a document describing what they are supposed to do.

The reference of "muxrpc" seems more confusing than helpful, as afaict muxrpc is just one implementation of the RPC Protocol described in the protocol guide. The calls are the requests sent by the client, I assume the testable implementation must be able to answer these calls, i.e. implement these RDF Procedures.