5 Use of the BSSAP on the E‑interface

09.083GPPApplication of the Base Station System Application Part (BSSAP) on the E interfaceRelease 1999TS

DTAP is used on the E‑interface for the transfer of messages between the MSC‑A and the MS.

The dedicated BSSMAP procedures (3GPP TS 08.08 subclause 3.1) used on the E‑interface to some extent are:

– assignment;

– handover resource allocation;

– handover execution;

– internal handover indication;

– release due to BSS generated reasons;

– classmark handling;

– cipher mode control;

– trace invocation;

– queuing indication;

  • data link control SAPI not equal to "0";
  • Location Acquisition.
  • LSA handling.
  • Common ID.

5.1 DTAP

For the exchange of the DTAP messages (3GPP TS 08.08 subclause 2.2), the involved MSCs shall act according to the following:

– the MSC‑A acts as the MSC;

– the MSC‑I acts as the BSS.

5.2 Assignment

The Assignment procedure (3GPP TS 08.08 subclause 3.1.1) is applied on the E‑interface with following conditions:

– the MSC‑A acts as the MSC;

– the MSC‑I acts as the BSS.

The handling of terrestrial resources is not applicable.

5.3 Handover resource allocation

At Basic Inter‑MSC Handover (3GPP TS 03.09) the Handover resource allocation procedure (3GPP TS 08.08 subclause 3.1.5.2) is applied on the E‑interface with the following conditions:

– the MSC‑A acts as the MSC;

– the MSC‑T acts as the target BSS.

At Subsequent Inter‑MSC Handover (3GPP TS 03.09) the Handover resource allocation procedure (3GPP TS 08.08 subclause 3.1.5.2) is applied on the E‑interface with the following conditions:

– the MSC‑I acts as the MSC;

– the MSC‑T acts as the target BSS;

– if the MSC that is the MSC‑A is not also the MSC‑T, then this MSC shall act as the target BSS towards the MSC‑I and as the MSC towards the MSC‑T.

The handling of terrestrial resources is not applicable.

5.4 Handover execution

For the Handover execution procedure (3GPP TS 08.08 subclause 3.1.5.3) the applicable parts on the E‑interface are the transfer of HANDOVER DETECT, HANDOVER COMPLETE and HANDOVER FAILURE messages at inter MSC handover. For those parts, the involved MSCs shall act according to the following:

– the MSC that is the MSC‑A, acts as the MSC;

– the MSC that is the MSC‑I, if it is not also the MSC‑A, acts as the serving BSS;

– the MSC that is the MSC‑T, if it is not also the MSC‑A, acts as the target BSS.

5.5 Internal handover indication

For the Internal handover indication (3GPP TS 08.08 subclause 3.1.6 and 3.1.7), the involved MSCs shall act according to the following:

– the MSC‑A acts as the MSC;

– the MSC‑I acts as the BSS.

MSC internal handovers (inter‑BSS and intra‑BSS handover) at the MSC‑I are decided and executed autonomously by that MSC together with the connected BSSs. At completion of the handover execution the MSC‑I initiates the internal handover indication procedure.

5.6 Release due to BSS generated reasons

For the Release due to BSS generated reasons procedure (3GPP TS 08.08 subclause 3.1.9.2) the involved MSCs shall act according to the following:

– the MSC‑I acts as the BSS;

– no further action is taken by the MSC‑A.

Additionally, at Basic Inter‑MSC Handover and at Subsequent Inter‑MSC Handover (3GPP TS 03.09), if the MSC that is the MSC‑A is not also the MSC‑T, the Release due to BSS generated reasons procedure (3GPP TS 08.08 subclause 3.1.9.2) is applied on the E‑interface with the following conditions:

– the MSC‑T acts as the BSS;

– no further action is taken by the MSC‑A.

5.7 Classmark handling

For the Classmark handling (3GPP TS 08.08 subclause 3.1.13), the involved MSCs shall act according to the following:

– the MSC‑A acts as the MSC;

– the MSC‑I acts as the BSS.

5.8 Cipher mode control

For the Cipher mode control (3GPP TS 08.08 subclause 3.1.14), the involved MSCs shall act according to the following:

– the MSC‑A acts as the MSC;

– the MSC‑I acts as the BSS.

5.9 Trace invocation

For the Trace invocation (3GPP TS 08.08 subclause 3.1.11), the involved MSCs shall act according to the following:

– the MSC‑A acts as the MSC;

– the MSC‑I acts as the BSS.

Additionally, at Basic Inter‑MSC Handover and at Subsequent Inter‑MSC Handover (3GPP TS 03.09), if the MSC that is the MSC‑A is not also the MSC‑T, the Trace invocation (3GPP TS 08.08 subclause 3.1.11) is applied on the E‑interface with the following conditions:

– the MSC‑A acts as the MSC;

– the MSC‑T acts as the target BSS.

5.10 Queuing indication

For the Queuing Indication (3GPP TS 08.08 subclause 3.1.17), the involved MSCs shall act according to the following:

– at Assignment and at Basic Inter‑MSC handover:

– the MSC‑A acts as the MSC;

– the MSC‑I acts as the BSS.

– at Subsequent Inter‑MSC handover:

– the MSC‑I acts as the MSC;

– the MSC‑T acts as the BSS;

– if the MSC that is the MSC‑A is not also the MSC‑T, then this MSC acts as the target BSS towards the MSC‑I and as the MSC towards the MSC‑T.

5.11 Data link control SAPI not equal to "0"

For the Data Link Control SAPI not Equal to "0" (3GPP TS 08.08 subclause 3.1.18), the involved MSCs shall act according to the following:

– the MSC‑A acts as the MSC;

  • the MSC‑I acts as the BSS.

5.12 Location Acquisition

For the Location Acquisition procedure (3GPP TS 08.08 subclause 3.1.28), the involved MSCs shall act according to the following:

– the MSC‑A acts as the MSC;

– the MSC‑I acts as the BSS.

5.13 LSA handling

For the LSA handling (3GPP TS 08.08 subclause 3.1.27), the involved MSCs shall act according to the following:

– the MSC‑A acts as the MSC;

– the MSC‑I acts as the BSS.

5.14 Common ID

For the Common Id (3GPP TS TS 08.08), the involved MSCs shall act according to the following:

  • the MSC‑A acts as the MSC;
  • the MSC‑I acts as the BSS.