8 Use of BSSAP-LE on the Lp Interface

09.313GPPBase Station System Application Part LCS Extension (BSSAP-LE)Location Services (LCS)Release 1999TS

8.1 Applicable Message Sets

The following BSSAP-LE messages are applicable to the Lp interface between an SMLC and a peer SMLC.

BSSMAP-LE Connectionless Information message

8.2 MTP Functions

SS7 signaling on the Lp interface may be supported using 56 kbps or 64 kbps digital signaling channels. These may be supported within either E1 or T1 physical links.

Two SMLCs may be connected by direct point-to-point SS7 signaling links or links may be employed via intermediate STPs. Alternatively, signaling transfer between two SMLCs may be supported via intermediate BSCs and/or MSCs using the Lb and/or Ls interfaces. Signaling requirements to support message transfer on the Lp interface via an intermediate Lb or Ls interface are the same as those defined elsewhere in this specification for these interfaces. This section defines the requirements applicable to direct SMLC-SMLC SS7 links and SS7 links from an SMLC to an STP.

For E1 links or where CCITT/ITU SS7 signaling is applicable, the MTP functions as specified in CCITT Recommendations Q.702, Q.703, Q.704 and Q.707 are applicable. For T1 links or where ANSI SS7 signaling is applicable, the MTP functions as specified in ANSI T1.111 are applicable. Only the requirements in these recommendations for a signaling end point are applicable.

Where an SMLC has no signaling links to an STP, certain exceptions and modifications to normal CCITT and ANSI requirements may be applied within a PLMN administration.

8.3 SCCP functions

8.3.1 General

For E1 links or where CCITT/ITU SS7 signaling is applicable, the SCCP functions as specified in either CCITT Blue Book Recommendations Q.711, Q.712, Q.713 and Q.714 or ITU White Book Recommendations Q.711, Q.712, Q.713 and Q.714 are applicable, as amended by the exceptions and modifications defined here. For T1 links or where ANSI SS7 signaling is applicable, the MTP functions as specified in ANSI T1.112 are applicable, as amended by the exceptions and modifications defined here.

8.3.2 Allowed Exceptions to CCITT Recommendations Q.711-714

Only the following SCCP messages are applicable to the Lp interface:

Inactivity Test (IT)

Subsystem Allowed (SSA)

Subsystem Prohibited (SSP)

Subsystem Status Test (SST)

Unitdata (UDT)

Unitdata Service (UDTS)

Support of only SCCP protocol classes 0 and 1 is required.

The SCCP called party address in a UDT may contain only the subsystem number (SSN) or a signaling point code (SPC) plus SSN or a global title. Use of a global title is not required for SMLC to SMLC signaling within the same PLMN. SSN values applicable to the Lp interface are defined in 3GPP TS 03.03.

8.3.3 Allowed Exceptions to ANSI T1.112

Only the following SCCP messages are applicable to the Lp interface:

Inactivity Test (IT)

Subsystem Allowed (SSA)

Subsystem Prohibited (SSP)

Subsystem Status Test (SST)

Unitdata (UDT)

Unitdata Service (UDTS)

Support of only SCCP protocol classes 0 and 1 is required.

The SCCP called party address in a UDT may contain only the subsystem number (SSN) or a signaling point code (SPC) plus SSN or a global title. Use of a global title is not required for SMLC to SMLC signaling within the same PLMN. SSN values applicable to the Lp interface are defined in 3GPP TS 03.03.

8.3.4 Usage of Connectionless SCCP

Connectionless SCCP messages and procedures shall be used to transfer BSSMAP-LE Connectionless Information messages. Refer to 3GPP TS 03.71 for a description of the procedures in the SMLC. SCCP protocol class 1 shall be used when multiple BSSMAP-LE messages are sent containing segments of a single fragmented SMLCPP message.

8.3.5 Usage of Connection Oriented SCCP

Connection oriented SCCP messages and procedures are not applicable to the Lp interface.

8.3.6 Contents of the SCCP Data Field

The contents of the SCCP data field is shown in the following figure.

8

7

6

5

4

3

2

1

Octet 1

0

0

0

0

0

0

0

D=0

Octet 2

Length indicator = n

Octet 3

to

Octet n+2

BSSMAP-LE Message Contents

Figure 8.3.6-1/3GPP TS 09.31: SCCP Data Field for a BSSMAP-LE Message

The Discrmination Indicator is coded in bit 1 of octet one and indicates the type of the BSSAP-LE message.

Discrmination Indicator

BSSAP-LE Message Type

0

BSSMAP-LE

The length indicator is coded in one octet, and is the binary representation of the number of octets of the subsequent BSSMAP-LE message parameter.