SAP
From TBwiki
The Service Access Point is used to bind the SIP stack with a transport server. Depending on the system configuration, multiple SAPS can be configured.
For example, signaling traffic to a proxy server can be transported over UDP, while another service can be transported over TCP. A distinct transport server (IP endpoint) is configured for each of these applications. In turn service access points are associated with one or more transport servers so that they can be easily and flexibly assigned to network access points (NAP).
