Interaction (RTP)

Introduction

A SIP call-control Lua script using LhoSipIncallLuaService or LhoSipOutcallLuaAgent may request that the A-Leg be connected to a locally generated RTP stream for the purpose of playing announcements with optional digit collection.

This requires that an RtpApp instance is running locally, and that RtpApp is configured as a known resource for the LhoSipApp which is controlling the call. The controlling LhoSipApp will perform the relevant A-Leg SIP messaging necessary to connect to the RTP stream, using one of:

• SIP INVITE Final Response with code 200 OK
• SIP INVITE Provisional Response with code 183 Session Progress
• SIP re-INVITE Request

Here is the overall flow for an interaction using the SIP INVITE Final Response mechanism to connect to a locally generated RTP stream:

Service logic processing will suspend until:

• The A-Party abandons the call, or
• The announcement for an interaction that does not require digit collection completes playing, or
• The A-Party meets the digit collection requirements (potentially including end character), or
• An internal interaction timer (guard, first digit, inter-digit) reaches the maximum allowed duration, or
• An internal processing error occurs.

The LhoSipIncallLuaService Interaction API (Internal/RTP)

.rtp_interaction [Asynchronous]

This method provides full access to the Interaction mechanism for the Internal RTP resource.

This method takes the following arguments:

The rtp_interaction method returns a Lua table with the following attributes.

Example (simple announcement):

local n2svcd = require "n2.n2svcd"
local incall_api = require "n2.n2svcd.sip_incall_service"

local scc = ...

local WELCOME_ID = 4022

incall_api.rtp_interaction ({ message_id = WELCOME_ID })

return

Example (one integer variable part):

local n2svcd = require "n2.n2svcd"
local incall_api = require "n2.n2svcd.sip_incall_service"

local scc = ...

local NUM_DAYS_ID = 1020

incall_api.rtp_interaction ({ message_id = NUM_DAYS_ID, variables = { integer = 356 } })

return

Example (collect 4 digit PIN):

local n2svcd = require "n2.n2svcd"
local incall_api = require "n2.n2svcd.sip_incall_service"

local scc = ...

local ENTER_PIN_ID = 1044

incall_api.rtp_interaction ({ message_id = ENTER_PIN_ID, collect = { min_num_digits = 4, max_num_digits = 4, private_digits = true }})

return

Example (play specific files with limited duration):

local n2svcd = require "n2.n2svcd"
local incall_api = require "n2.n2svcd.sip_incall_service"

local scc = ...

incall_api.rtp_interaction ({ duration = 4, files = { 'a/Goodbye', 'announcements/Goodbye', 'v/1', 'a/Welcome_To_Demonstration', 'a/Welcome_To_Demonstration' } })

return

.set_language [Pure Lua]

The set_language method sets the default language for all subsequent interactions.

Note: this method affects interactions with both the Internal RTP resource and External INAP-controlled SRFs.

This method takes a single argument:

The set_language method returns true.

.set_early_media [Pure Lua]

The set_early_media method sets the Early Media preference for all subsequent SIP incall Internal RTP resource interactions.

Note: Early Media does not apply to interactions associated with SIP outcalls or External INAP-controlled SRFs.

This method takes a single argument:

The set_early_media method returns true.

The following relevant constants are defined on the sip_incall_service object:

sip_incall_service.EARLY_MEDIA_REQUIRE = "require"
sip_incall_service.EARLY_MEDIA_PREFER = "prefer"
sip_incall_service.EARLY_MEDIA_ALLOW = "allow"
sip_incall_service.EARLY_MEDIA_NEVER = "never"