This object represents the Registration address used
in SIP protocol. Users in a SIP network are identified
by unique SIP addresses. A SIP address is similar to an
e-mail address and is in the format of
'sip:userID@gateway.com'. The userID can be either a
user name or an E.164 address. An E.164 address is a
telephone number with a string of decimal digits that
uniquely indicates the public network termination point.
The number contains the information necessary to route
the call to this termination point.