User agents have client and server components. Kerberos allows for mutual authentication between client and server. The software consists of both a client and server component. This reduces the requirement of persistent connections between server and client application. The nature of communication between a client and server is request and response. Job Tracker receives the requests for Map Reduce execution from the client. IO libraries on both client and server side. The restrictions imposed by HATEOAS decouple client and server. The user agent client (UAC) sends SIP requests. ScatterChat is an encrypted instant messaging client based on Gaim. The user part is the username reported by ident on the client. There have been some reported issues with the Web client. The CHADDR is set to the MAC address used by the client. All members are responsive to client data queries. These tests then communicate with Selenium by calling methods in the Selenium Client API.