User Manual

ArchitectureNortel Networks Confidential 3–25
S8000/S8002/S8006 BTS Reference Manual
3.3 CBCF functional architecture
The CBCF performs the following functions:
switching, synchronization, and concentration
control of the alarm management unit
PCM Interface
The CMCF board performs the concentration, synchronization, and switching
functions. The CMCF also controls the alarm management unit (the RECAL
board), which is located outside the CBCF Module.
The CMCF board allows operation in duplex mode and in simplex mode.
The CPCMI board is the interface between the external PCM links (A–bis) and the
Private PCMs in the CBCF.
CBCF modes
The CBCF can be used in simplex mode with only one CMCF board in slot 0 or 1
running in active mode. Simplex/Duplex mode is managed by a micro switch on the
CMCF board. From duplex to simplex, the transaction in never automatic, it always
follows a configuration. From simplex to duplex mode, there is no automatic
transition when the active board detects the connection with the passive one.
3.3.1 Switching, synchronization, and concentration
The CMCF board is duplicated in the CBCF Module to provide redundancy (see
Figure 3–7).
One CMCF central processor manages the switching matrix and the
synchronization. The main processor and slave processor share the concentration
and routing tasks as described below.
3.3.1.1 Switching
The two switching matrices in the CMCF receive and distribute the traffic of
external PCMs as follows:
up to six PCMs communicate with the CPCMI boards
up to six PCMs communicate with the DRXs
two PCMs communicate with the processing units
one PCM to communicate GSM time
one PCM for tests