Editing Signalling System No. 7 (section)

===BSSAP===
'''BSS Application Part''' ('''BSSAP''') is a protocol in SS7 used by the [[Network switching subsystem#Mobile switching center (MSC)|Mobile Switching Center]] (MSC) and the [[Base station subsystem]] (BSS) to communicate with each other using signaling messages supported by the [[Message_Transfer_Part|MTP]] and [[Connection-oriented communication|connection-oriented services]] of the [[Signaling_Connection_Control_Part|SCCP]]. For each active [[Mobile station|mobile equipment]] one signaling connection is used by BSSAP having at least one active transactions for the transfer of messages.<ref>{{cite web|url=https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=2759|title=3GPP TS 48.008, Mobile Switching Centre - Base Station System (MSC-BSS) interface; Layer 3 specification}}</ref> 

BSSAP provides two kinds of functions:

* The BSS Mobile Application Part (BSSMAP) supports procedures to facilitate communication between the MSC and the BSS pertaining to resource management and [[handover]] control.
* The Direct Transfer Application Part (DTAP) is used for transfer of those messages which need to travel directly to mobile equipment from MSC bypassing any interpretation by BSS. These messages are generally pertaining to [[mobility management]] (MM) or [[call management]] (CM).