10.2.10. Signaling and Payload Separation (SPS) 
IMPORTANT:
Signaling and Payload Separation (SPS) is released
for standalone systems only! In networked environment a project specific
release (PSR) is required and only basic call is possible!
Signaling and payload separation is a feature which enables OpenScape
4000 in an IPDA environment to split the path of the network traffic
in the meaning of
- signaling from Hostsystem (call control) to access point is routed over
the IP Customer Network (Enterprise WAN)
- payload is routed over the PSTN Network using payload survivability connections (e.g. calls from host system to an access point is automatically routed via CO).
IMPORTANT:
SPS connectivity and features are only supported for IP Access Points and host shelves (LTUs) that are controlled by the central communication server (host system). If an IP Access Point goes in AP Emergency survivability mode, then SPS connectivity and features are no longer possible/supported. For IP Access Points in AP Emergency mode all calls to other IP Access Points and host shelves will be routed over PSTN based on the AP Emergency LCR routing configuration with basic call functionality.Signaling and payload separation based on existing survivability solution and therefore the signaling path is routed in the same way as today.Signaling and payload separation can be configured in a way that- payload separation is always active (static signaling and payload separation)
- payload separation is used in case of limited WAN- bandwidth managed by the resource manager or overflow scenarios when then maximum of bandwidth is reached (payload overflow)
- payload separation is used in case of network failure (emergency routing)
- If a subscriber specifies via access code that he does not wish to use IP. In this case payload separation with all access points configured in different source groups can be used
In this situation all access points have to be assigned in different source groups and CO access will be mandatory for all access points.All calls between access points and between access points and host system will be made over ISDN lines.