SilentKnight VisorALARM High Availability Receivers - Manual (Page 4)

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1. System topology and operation
Main Internet
Access line
Backup Internet
Access line
Figure 1. IP network diagram for CMS High Availability
Normal operation
The IPDACT-2/2UD only communicates with the Main VisorALARM receiver over the
main CMS line. The main VisorALARM hence deals with the three IP traffic flows -
registration, alarm transmission and supervision – delivered by all IPDACT-2/2UD’s on
field. The main Communication path of this IP traffic in the CMS network is depicted in
green in the above Figure.
Operation in Emergency
Upon a main link failure the IPDACT-2/2UD switches the transmission over the backup
CMS line to the backup VisorALARM. The backup VisorALARM is taking the roll of a
main VisorALARM, serving all IPDACT-2/2UD’s on field just as if it was the main one.
The backup Communication path is colored red in Figure 1. On the other hand, the