User Manual

Software descrIption
Nortel Networks Confidential
4–14
PE/DCL/DD/0063
411–9001–063
Standard 12.07/EN September 2000
GSM/BSS V12
4.2.3.1 PCM Management
This function selects one of the incoming PCMs for communication with the BSC.
It then routes PCM TSs to the appropriate equipment in the BTS as the BSC
requests. Other PCM TSs are routed toward another PCM to allow drop & insert
functionality.
This function also ensures LAPD concentration.
4.2.3.2 Configuration and supervision management
This function translates the OML A–bis model into a physical model to offer a
standardized configuration and supervision to the BSC. The CBCF acts as an A–bis
front end toward the BSC for configuration and supervision purposes. It is the only
link for configuration messages coming from the BSC. The CBCF uses the
CBCF/DRX protocol to drive any actions concerning the DRX
4.2.3.3 Software management
The CBCF performs software management for the BTS and provides the only link
for downloading messages from the BSC. When a RECAL or CPCMI board is
downloaded, the CBCF/Slave protocol is used.
4.2.3.4 Synchronization management
The CBCF builds the GSM time and provides it to the DRX via a TS or a private
PCM. External PCMs ensure long term stability.
4.2.3.5 Test Management
The CBCF coordinates all BTS tests. When an installation or maintenance action
affects a DRX, the DRX is driven by the CBCF using the CBCF/DRX Protocol.
4.2.3.6 Duplex Management
The COAM software manages a cold and hot duplex modes.