ence</em>, for short). AppSwitch implements service references based on the API instrumentation mechanism outlined above. A service reference consists of an IP:port pair (and optionally a DNS name) and a label-selector that selects the service represented by the reference and the clients to which this reference applies. A reference supports a few key properties. (1) It can be named independently of the name of the object it refers to. That is, a service may be listening on an IP and port but a reference all