Enable T.38 Fax Over Ip Relay; Configure Registration Authentication Service In An H.323 Gateway - Patton electronics SmartNode Series Software Configuration Manual

SmartWare Software Configuration Guide

Enable T.38 fax over IP relay

T.38 is an ITU-T protocol for the transmission of fax (T.30) over IP. In T.38 the fax signal is demodulated at
the sender side and transmitted over UDP or TCP over the IP network to the receiver which in turn modulates
the signal to T.30 again.
Note
Fax relay with T.38 must be enabled in the VoIP profile, either the default
profile or a specifically configured VoIP profile.
This procedure describes how to enable the H.323 gateway to transmit fax with the T.38 protocol
Mode: Gateway H.323
Step
1 node (gw-h323)[h323]#codec t38_udp
Configure registration authentication service in an H.323 gateway
As mentioned in previous chapters a call setup can use direct call signaling and gatekeeper routed call signaling.
For gatekeeper routed call signaling the H.323 network needs a gatekeeper device. Gatekeepers manage H.323
zones, which are logical collections of devices such as all H.323 devices within an IP subnet. Gatekeepers for
example provide address translation (routing) for the devices in their zone. This could be, for instance, the
translation between internal and external numbering systems. Another important function for gatekeepers is
providing admission control, specifying what devices can call what numbers.
To use the gatekeeper the SmartNode has to register by the gatekeeper, therefore the registration authentication
service has to be enabled. The SmartNode has to register by a name or names, therefore some aliases have to be
specified. Furthermore the gatekeeper discovery could be specify on automatically or manually.
Normally the remote IP address specified in the CS interface is not set if gatekeeper routed call signaling is enabled,
because the gatekeeper supplies the remote destination IP address. Nevertheless the remote IP address is set in the CS
interface the call over this interface goes to the specified IP address but the gatekeeper will be asked for permission.
Redundancy is of great importance in communications networks. An H.323 gatekeeper offers a critical service in
a network—failure of a single gatekeeper may result in non-availability of the voice service in the entire network.
The SmartNode allows configuring up to three different gatekeeper addresses. These addresses are used for RAS in
a round-robin fashion. Once communication with one of the gatekeepers is lost the SmartNode falls back to the
next address in the list. All entries from the list can be removed by applying the no form of the command.
Note
If you have to change the call signaling port use the command 'call-signal-
ing-port' in the H.323 gateway configuration mode.
This procedure describes how to enable the registration authentication service.
Gateway configuration task list
Command
29 • Gateway configuration
Purpose
Enables T.38 operation if the gateway detects a
fax signal from one of the PSTN lines.
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