NAP
A Network Access Point or NAP represents the entry point to another network or destination peer (e.g. SIP proxy, ISUP interface peer, etc). A NAP can also be thought of as a 'trunk group'.
TelcoBridges and Network Access Points
The Network Access Point (NAP) allows for service access points (SAPs), ISDN stacks, and SS7 ISUP interfaces to be associated as a combined resource for one type of access. A NAP is used to represent a collection of voice endpoints, for example: a group of SS7 CICs, ISDN controlled timeslots, SIP outgoing proxy to a specific provider, and more. NAPs are, later in the configuration process, used to define how calls are routed out of the Tmedia system.
In the SS7 world, the term 'trunk group' is often used to refer to what is called a NAP in Toolpack's terminology.