Advantech MIC-3369C Guia de Instalação descarregar pdf (Página 29)

Dialogic

System Release 6.1 CompactPCI for Windows

Release Update 29

1.6 Handling non-2xx Responses to T.38 Switch

Service Update 194 introduces Global Call support for RFC3261 compliance for non-2xx

responses to re-INVITE requests to switch to or from audio to T.38 fax and back. This

feature has been tested on Dialogic

IPT Boards.

1.6.1 Feature Description

Currently, when a Global Call SIP application initiates a media type switch from/to audio

or to/from fax within a dialog with a re-INVITE request, the existing media session and

dialog are terminated on a non-2xx response from the UAS. RFC3261 clearly requires

that the UAC keep the exiting session alive in a dialog as though the re-INVITE never

occurred.

With this feature, the existing media session remains active within the dialog upon a

switching request from one media type to another (fax to audio or audio to fax).

This feature is enabled by default when the application calls the gc_ReqModifyCall( )

function or the gc_Extension( ) function with the codec switch value. On failure to switch,

the application will receive the failure events,

GCEV_REQ_MODIFY_REJ/GCEV_REQ_MODIFY_FAIL and the GCEV_EXTENSION

event with parm ID set to IPPARM_REJECT for set ID IPSET_SWITCH_CODEC

respectively. The existing media session will be reestablished underneath and the

requested local media information will be overwritten with the stored (existing) media

information.

Because this feature is limited to “Manual” operating mode, an application must be

configured in “Manual” mode to control the association and disassociation of media and

T.38 fax devices during each call. The mode of operation is set on a board device basis.

The operating mode for set ID/parm ID pair

IPSET_CONFIG/IPPARM_OPERATING_MODE must be set to either of the following:

• IP_T38_MANUAL_MODE

• IP_T38_MANUAL_MODIFY_MODE

For additional information, refer to the documentation updates for Chapter 3. IP Call

Scenarios and Chapter 4. IP Specific Operations in the Dialogic Global Call IP

Technology Guide.

1.6.2 Manual Mode Example

This example demonstrates “Manual” mode when the switch from T.38 fax to audio is

unsuccessful.

INT32 switchFromFaxToAudio( )

{

GC_PARM_BLK *parmblkp = NULL;

IP_CONNECT ipConnect;

ipConnect.version = 0x100;

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