Inalp Networks SmartWare Release 2.10, Руководство по настройке программного обеспечения

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290 Gateway Configuration
SN(gw-h323)[h323]# exit
SN(cfg)# context cs
SN(ctx-cs)[switch]# interface h323 H323
SN(if-h323)[H323]# codec g711alaw64k
SN(if-h323)[H323]#
Note: There is more than one possibility to establish a H.323 connection faster. Faststart is one of
them. Another is to exchange H.245 messages soon (before the CONNECT message of the
H.323 call signaling). This feature is enabled per default. If some compatibility problems pass,
this feature could be disabled with the command ‘no early-h245’.
30.3.4 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 that fax relay with T.38 must be enabled in the VoIP profile, either the default profile or a
specifically configured VoIP profile.
Procedure
Enable the H.323 gateway to transmit fax with the T.38 protocol
Mode
Gateway H.323
Command Purpose
Step 1 node (gw-h323)[h323]#codec
t38_udp
Enables T.38 operation if the gateway detects a
fax signal from one of the PSTN lines.
30.3.5 Called- and Calling Party Number Port Mappings and B-Side Codec
Selection with isoip-sp Q.931 Tunneling
When using Q.931 tunneling as per isoip-sp wider control over B-side (receiving side) codec selection
can be attained. This can be useful if the H.323 network (i.e. gatekeepers, endpoints, gateways) does
not support switching the codec dynamically (on the fly) after the call has been established.
Especially for modem and facsimile G.3 connections it is required to force a loss-less codec (G.711 A-
law or G.711 u-law) to be used in both directions of the connection. For outgoing calls (SmartNode is
A-side) the SmartNode selects the specified codec (and only that one) based on the calling party
number. Conversely the SmartNode on the B-side selects the specified codec based on the called
party number. Provided that a SmartNode is employed on the A- and/or on the B-side this will
guarantee that modem and facsimile G.3 calls will be established only with the specified (loss-less)
codec or dropped if the offered codec is not supported by the peer.
In addition to B-side codec selection the called party number to port number mapping allows the
SmartNode to route ISDN broadcast messages to the appropriate ISDN port. As only a called party
number is provided in the incoming H.323 message (containing a tunneled ISDN message) a
mapping table from called party number to ISDN physical port number is required.
Note: This command is only applicable when using Q.931 isoip-sp tunneling.
Procedure
To configure codec and port mappings for A-side and B-side codec selection.
Software Configuration Guide Release 2.10, Revision 1.00
Mode
Gateway H.323