Service Address

A Service address consists of two parts, assigned by the developer

  • A Service Type number – typically hard-coded
  • A Service Instance number – often calculated by user in run time

A service address is always qualified by a scope indicator

  • Indicating lookup scope on the calling side
  • node == 0 indicates cluster global lookup
    node != 0 indicates that lookup should be performed only on that node
  • Indicating visibility scope on the binding side
  • There are dedicated values for node local or cluster global visibility

Service Address Binding

There are almost no restrictions on how to bind service addresses

  • Different service addresses can be bound to same socket
  • Same service address can be bound to different sockets
  • Service address ranges can be bound to a socket
  • Only one service address per socket in message bus mode
  • This address type is also used for sending datagram and
    communication group multicast

Location Transparency

A client doesn't need to know the location of the server

  • Translation from service address to socket address is performed on-the-fly at the source node.
  • There is a replica of the global binding table on each node for performing this translation.
  • A sender can still indicate an explicit socket address when that is more practical,. e.g., when just responding to an incoming message.