VoIP gateway IP400 version 5.01
Page 69
6.1.1 Understanding your gateway's gatekeeper
There are basically two tasks that the gatekeeper has to carry out:
• Management of the terminal equipment (device management).
• The switching of voice calls (call switching).
Both functions are features of your gateway, although device management is
optional.
Fig. 19 Call sequence with a gatekeeper and RAS
Fig. 19 on page 69 shows a scenario with an IP telephone, an ISDN gateway and
a gatekeeper. The gatekeeper can be another innovaphone gateway or, alter-
natively, it can be the gatekeeper incorporated in every innovaphone gateway. For
a clearer understanding though, the gatekeeper and ISDN gateway are shown
separately.
The individual steps of a call which are relevant in this context are displayed in
the following. In reality, the procedures can be far more complex.
• Both the IP telephone (1.) and the ISDN gateway (2.) register with the gate-
ga
tek
eepe
r
Legend:
---- Device management (RAS)
......Call signalling (H.225)
___Voice data (RTP)
IP telephone
Eqpt.
mgmt.
Call
switch-
ing
ISDN
Gateway
ISDN