文档介绍：Message Interpretation
Here will give message contents of some key interface messages, these include: A-interface key messages, Abis-interface key messages.
A-Interface Key Messages
There is no general rule for the order of signaling elements: it happens that the same elements appear in various orders depending on the message. The messages of A-interface described here are based on Phase 2+ GSM 0808 version Release 1998.
The key BSSMAP messages are listed in the following table:
Message name
Reference
ASSIGNMENT REQUEST

PLETE

ASSIGNMENT FAILURE

HANDOVER REQUEST

HANDOVER REQUEST ACKNOWLEDGE

HANDOVER REQUIRED

HANDOVER REQUIRED REJECT

MAND

PLETE

HANDOVER FAILURE

HANDOVER PERFORMED

PAGING

CLEAR REQUEST

MAND

CLASSMARK REQUEST

CLASSMARK UPDATE

CIPHER MAND

CIPHER PLETE

CIPHER MODE REJECT

COMPLETE LAYER 3 INFORMATION

Message Contents
ASSIGNMENT REQUEST
This message is sent from the MSC to the BSS via the relevant SCCP connection in order to request the BSS to assign radio resource(s), the attributes of which are defined within the message.
The message may also include the terrestrial circuit to be used.
INFORMATION ELEMENT
REFERENCE
DIRECTION
TYPE
LEN
Message Type

MSC-BSS
M
1
Channel Type

MSC-BSS
M
5-10
Layer 3 Header Information

MSC-BSS
O (3)
4
Priority

MSC-BSS
O
3
Circuit Identity Code

MSC-BSS
O (1)
3
Downlink DTX Flag

MSC-BSS
O (2)
2
Interference Band To Be Used

MSC-BSS
O
2
Classmark Information 2

MSC-BSS
O (4)
4-5
Group Call Reference

MSC-BSS
O (5)
3-8
Talker Flag

MSC-BSS
O (6)
1
LSA Access Control Suppression

MSC-BSS
O (8)
2
1. This element is included when the MSC allocates the A-interface circuits and the channel type Information Element ind