TD 92326GB
2009-03-10 / Ver. E
Installation and Operation Manual
VoIP Gateway
137
19.1.4 Setting up a Gatekeeper on another VoIP Gateway
If the gatekeeper is not to operate on its own VoIP Gateway, a remote gatekeeper address
can be configured in the “Gatekeeper” area.
The VoIP Gateway tries to log onto a remote gatekeeper if its IP address is entered in the
(primary) “Gatekeeper ID“ field. If the attempt to register is unsuccessful, the VoIP
Gateway tries to log onto an alternative gatekeeper, provided an alternative address has
been entered in the (secondary) “Gatekeeper address” field.
It is important to enter an alternative gatekeeper IP address, especially when using
redundant systems.
If the gatekeeper operates with a gatekeeper ID (see section
on page 135), type it in the “Gatekeeper ID” field.
The Password corresponds to the H.235 password required for logging on to the remote
gatekeeper.
By clicking on the “Disable dynamic signalling port” button, a fixed Signalling port can be
entered, which, for example, can be configured on firewall systems.
19.1.5 Voice Transmission
The VoIP Gateway supports various methods of voice transmission using IP. For calls
between one of the VoIP Gateway's ISDN interfaces and a VoIP device defined by this VoIP
interface, you can make the relevant definitions in the “Media Properties” area.
Note that calls between two VoIP devices, for example from IP to IP, do not take this
setting into account since the parameters are negotiated directly by the terminals and their
configuration is thus relevant.
Voice coding
There are various ways of encoding voice transmission. Some of the available encoding
options compress speech, others do not. The VoIP Gateway supports various standard
voice-encoding schemes whose properties are described in the following table:
Suppress HLC
Prevents the transmission of so called “high layer compatibility”
(HLC) information elements. This is required if the receiving VoIP
device responds erroneously to HLCs. Otherwise the HLCs are
forwarded transparently by the gatekeeper. Only use this option if a
VoIP device with this kind of fault needs to be used. Do not use this
option when linking PBX systems via VoIP Gateways, since
otherwise under certain circumstances important information could
be lost.
Suppress FTY
Prevents the transmission of so called “facility (FTY) messages”. This
is required if the receiving VoIP device responds erroneously to FTYs.
Otherwise the FTYs are forwarded transparently by the gatekeeper.
Only use this option if a VoIP device with this kind of fault needs to
be used. Do not use this option when linking PBX systems via VoIP
Gateways, since otherwise under certain circumstances important
information could be lost.
Suppress
subadress
Suppresses the transmission of “Subaddresses” on the interface.
a.From a technical viewpoint, the H.245 protocol doesn't establish its own TCP connection, but
shares the H.225 TCP connection.
