Resource manager contact the resource manager contact string is used by the gram client to connect to, authenticate to, and request service from a gram resource manager. the simplest contact string is just a host name, but additional fields may be present in the name to qualify the tcp port number it is listening on, the service name (for example, to choose a specific scheduler), and the subject name (security identity) of the resource manager. for those resource manager contacts which omit the port, service or subject field the following defaults are used: