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The UI frame structure of LapDm is shown in Figure 20.
F
2 0 U I F
S
I G U R E
R A M E
Address
SAPI
The UI frame in LapDm consists of the address field, control field and
information field. The address field contains the SAPI. In the address
field, P represents the query bit; if this bit is set to 1, it means to
require the response frame from the opposite-end peer entity.
RR/MM/CM Protocol
The RR/MM/CM protocol, including three sub-layers of CM, MM and RR, is
responsible for control and management; it groups and arranges the
information of the subscriber and system control process into the
designated logical channels according to certain protocol packets.
1. CM Layer: It is responsible for communication management. It
establishes connections between subscribers, and holds and releases
calls. This layer provides call control (CC), supplementary service
management (SSM) and short message service (SMS).
2. MM layer: It is responsible for mobility and security management,
namely, the necessary processing when the MS initiates location
updating.
3. RR layer: It is responsible for radio resource management. It
establishes and releases connections between the MS and MSC during
the call process.
In ZXG10 OB06 (V1.0), the radio resource management module and
paging module of RSL are used to implement the RR/MM/CM protocol, and
perform the processing of transparent and non-transparent messages in
L3.
Transparent messages: ZXG10 OB06 (V1.0) is responsible for transferring
that kind of messages, without any analysis or change.
Non-transparent messages: They are only transmitted between the BSC
and ZXG10 OB06 (V1.0), and are processed by the ZXG10 OB06 (V1.0)
according to the specific message contents.
1. Um interface
The signaling on the Um interface includes all messages of RR, MM and
CM, and most of the messages are transparent to the ZXG10 OB06
(V1.0).
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T R U C T U R E O F
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Control Information
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P
Confidential and Proprietary Information of ZTE CORPORATION
Chapter 3 - Interfaces and Communications
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