ZTE Corporation ZXG-BTS2 用户手册

 
 

Chapter 3 - Interfaces and Communications 

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1.  In a Dm channel, providing a point-to-point data link connection and 

multiple services for the upper layer. The data link connections are 
identified by the DLCIs in the respective frames. The DLCI only 

contains SAPI, indicating the service that is accessed. 

2.  Supporting the identification of diversified frame types. 
3.  Supporting the transparent transmission of the L3 message between 

respective L3 entities. 

4. Sequence control, to maintain the sequence of respective frames 

connected via data link. 

5.  Checking the format and operation errors in the data link layer. 
6.  Notifying the L3 entities to process the unrecoverable errors. 
7. Flow control 
8.  Supporting access of the burst solution mode after the RACH channel 

access is instantly assigned. 

In the ZXG10-BTS(V2.9), LapDm is implemented in the LapDm module of 

RSL. 

The position of LapDm module in RSL is shown in Figure 27. 

LapD Module

OAMM

FURRM

Physical Layer

 

 

The LapDm module communicates with the physical layer and L3.The L3 
protocol is processed in FURRM.OAMM configures the value of the timer 

necessary for LapDm module to run. 

The LapDm module provides the FURRM with two information transmission 

modes: UI frame operation and I-frame multi-frame operation. In terms of 
frame structure, LapDm cancels the frame delimiter flag (FLAG) and the 

FCS (Frame Check Sequence).In LapDm, the synchronization scheme of 
the radio interface can be used to transmit the boundary message without 
the corresponding start frame or end frame flags. The transmission 

scheme provided by the physical layer of the Um interface boasts the error 
check function, so frame check sequence (FCS) is not used for LapDm. 

1.  I-frame multi-frame operation