scope:

This Technical Specification (TS) specifies the layer 3 procedures used on the Base Station System (BSS) to Mobileservices Switching Centre (MSC) interface for control of GSM services.

For the purposes of call control and mobility management, messages are not interpreted at the Base Station System (BSS) which acts as a relay function. These messages and procedures are documented in GSM 04.08, the only relevant issues covering these messages in this TS are those concerned with error conditions at the interface, and the headers that are required for the correct addressing of the messages. This is specified in more detail in GSM 08.06.

The functional split between MSC and BSS is defined in GSM 08.02 and states that the BSS is responsible for local radio resource allocation and in order to support this the required procedures between BSS and MSC are defined in detail in this Technical Specification.

GSM 08.02 also states that the BSS is responsible for the scheduling of all CCCH/BCCH messages and therefore some procedures for providing the BSS with the necessary information to be passed on these channels for individual calls (i.e. paging) are defined in this Technical Specification, but the scheduling is not discussed.

This interface and consequently these layer 3 procedures are designed to support BSSs providing one or more cells.