13.1.3. HSR via UDP 
The "HSR (HiPath Signaling Router) over UDP" feature
- concerns the signaling connection between the host system and Access Point/OpenScape 4000 SoftGate. The signaling connection between APE and Access Point/OpenScape 4000 SoftGate is not affected. The latter is always only a pure TCP/IP connection regardless of the configuration of the SIGMODE parameter in AMO UCSU.
- can/may be activated additionally for "Signaling Survivability via the public CO" in order to bypass firewalls.
- must be activated for using the "Signaling Survivability over alternative LAN" feature.
- can/must be activated/deactivated individually for each Access Point/OpenScape 4000 SoftGate (AMO UCSU, SIGMODE=HSRUDP).
IMPORTANT:
The customer IP network (firewall) must not block the
UDP 4000 and 4050 ports.