The Metis design imposes minimal requirements on service developers. They are free to implement services in any language. Communication between the service and the client-resident service stub can use any protocol, e.g., IIOP [5], RMI [4], or a private protocol. The service providers may provide a client-side stub with a well-known interface for access to its services, or, may only provide a location for AFEs to access services using a mutually understood protocol. The AFEs and service providers may use the authorization object provided by Metis for authentication purposes.
To better integrate services into the network, Metis provides a tool
that can be used to register the services with the Metis
Directory Service. For AFEs to dynamically access services, they must
be registered with the directory.
Registering a service makes it immediately available.
Removing a service from the Metis Directory Service does not
impact AFEs currently using the service. However, when an AFE detects
that the service is no longer available, i.e., the service was
removed from the server, it can fail-over to another service
registered in the Metis Directory Service.