The service advertisement service (SAS)

When a developer creates a service they need to make its access point netlets ``generally available''. If they write the service on their home PC or behind a firewall then its lifetime and availability is limited.

A service advertisement service is just a download point for netlet descriptors and JARs (so ``advertise'' is admittedly misleading). So once our developer uploads their netlet descriptors and JARs they no longer need to stay connected to the network; their netlets are still available.

Figure: Using the service advertisement service (SAS). (1) A developer advertises their service to the SAS. (2) In return they get a warrant which they give to their application netlets. (3) and (4) An application netlet uses the warrant to bind to the developer's service.

After uploading, the developer gets a warrant which points to the upload locations (now download locations) of the descriptors and JARs. They can give this to client netlets which want to use the service. These clients use the warrant to bind to the developer's service. The fact that it is handled by the SAS is irrelevant to them. The owner of the SAS is responsible for keeping it generally available. See Figure . Notice that we do not define how the developer gives the warrant to the client netlets--that's down to the contract between them.

Depending on the sophistication of the SAS it may allow static descriptors to be advertised (and delivered) or perhaps something more interesting, where the descriptor delivered varies based on particular circumstances. See also Section .