Patent ID: 7243159

Claim:
A network device, comprising: a port to allow reception of an incoming call at a first endpoint; a memory to store endpoint identifiers and associated capability information; and a processor to: determine an identifier of a second endpoint from the incoming call; access the associated information for the second endpoint, if it exists; set a first field value for the first endpoint to one of status codes including unknown, known and changed, and known and unchanged, depending upon the availability of any associated capability information; transmit a message including the first field value from the first endpoint to the second endpoint; and perform a capabilities exchange with the second endpoint, if necessary, depending upon the first field value of the first endpoint and a second field value received from the second endpoint, where the second field value is set to one of status codes including unknown, known and changed, and known and unchanged, wherein capabilities exchange is avoided only when the first field value is set to known and unchanged and the received second field value is known and unchanged.