|
|
|
|
|
Type of feature
Media Resource Control Protocol (MRCP) is an optional feature used to connect to speech engines other than those supported by the original speech proxy.
About MRCP
Interactive voice response applications typically rely on the recognition of caller speech (via Advanced Speech Recognition or ASR) and the use of synthesized voice in system responses (via Text-to-Speech or TTS). Prior releases of Avaya IR required a proprietary integration for each vendor's ASR and TTS system.
MRCP is an emerging, open standard for speech interfaces that supports the interoperability of vendor systems. MRCP addresses the communications between interactive voice response systems like Avaya IR and specialized speech engines (including but not limited to those that support ASR and TTS functionality).
When installed on Avaya IR , the MRCP feature enables integration with ASR and TTS engines running on an IBM WebSphere Voice Server (WVS) for Multiplatforms V5.1. This expands the range of vendor options to those deploying voice response applications and systems.
The MRCP feature on Avaya IR includes the following optional software packages:
The MRCP feature is compliant with the MRCP V1 draft 4 specification (as defined by the Internet Engineering Task Force Internet Draft draft-shanmugham-mrcp-04, originally posted at http://www.ietf.org/ietf/lid-abstracts.txt). For information about IBM WVS for Multiplatforms V5.1, see Third-party product documentation.
MRCP connections and protocols
The Avaya IR MRCP implementation does not use the Real-time Control Protocol (RTCP), the control protocol normally used with RTP. Avaya IR does not send, nor does it expect to receive, RTCP packets.
Avaya IR communicates with MRCP servers using two different protocols:
The two protocols use different ports and port ranges.
Avaya IR with MRCP supports sending the following RTSP methods and receiving their associated responses:
Avaya IR with MRCP supports receiving the following RTSP methods and responing accordingly:
All other received methods are ignored.
Avaya IR sends the RTSP DESCRIBE message with a sequence number of 0 to initially verify its connection to the MRCP server and periodically as a heartbeat to confirm the server's ongoing connection. Responses to the DESCRIBE message with a sequence number of 0 confirm that the MRCP server is still connected and active.
ASR requests and responses
Avaya IR supports sending the following MRCP requests for ASR resources and receiving their associated responses:
Avaya IR supports receiving the following MRCP events and responding accordingly:
All other events are ignored.
TTS requests and responses
Avaya IR supports sending the following MRCP requests for TTS resources and receiving their associated responses:
Avaya IR supports receiving the following MRCP events and responding accordingly:
All other events are ignored.
SSML incompatibilitites
Avaya IR and IBM WVS for Multiplatforms V5.1 support different versions of the Speech Markup Language specification:
This difference leads to the potential for TTS problems. For example:
The current known SSML incompatibilities appear in the following table.
Element |
Description |
say-as |
Avaya IR R1.2.1 supports the type attribute. Avaya IR R1.3 supports the interpret-as attribute. IBM WVS supports the interpret-as attribute. |
prosody |
Avaya IR R1.2.1 and R1.3 do not use HZ in the contour attribute. IBM WVS expects HZ in the contour attribute. |
Note:
This is not a complete list. Other incompatibilities may exist.
Such incompatibilities may result in synthesized speech not playing in applications, and the underlying cause may not be immediately obvious to the application developer. The problem occurs in the following ways:
To isolate the cause of such problems, run application traces on both the Avaya IR and IBM WVS sides.
Hardware requirements
There are no hardware requirements for the MRCP feature.
Software requirements
The MRCP feature works on Avaya IR Release 1.2.1 or later.
Both MRCP packages (ASR and TTS) require the Speech Proxy package (AVsproxy). Furthermore, the MRCP ASR package also requires the Speech Proxy SR - Speech Recognition package (AVsrproxy) and the MRCP TTS package also requires the Proxy Text-to-Speech package (AVttsprxy).
Once the MRCP feature is installed and configured, it can integrate with vendor ASR and/or TTS engines supporting MRCP that are installed on a separate server. Currently, this includes IBM WVS V5.1.
Set-up considerations
For any given speech technology (either ASR or TTS), an Avaya IR system can be configured to support either an MRCP-compliant engine or the original set of vendor engines, but not both at the same time. Specifically:
Note, however, that:
When multiple Avaya IR systems share the same LAN, some can be configured to support MRCP-compliant engines and others can support non-MRCP engines.
Avaya IR with MRCP supports all of the ASR and TTS languages supported by IBM WVS V5.1, subject to the WVS limitation of running one language per server. As a result, Avaya IR can be configured in the following ways:
Application development considerations
TTS applications created using Avaya IVR Designer may inadvertently insert TTS requests that have nothing except a blank space in them (for example, say " ").
Such a request causes problems for the IBM WVS V5.1, because the request does not complete.
An update fixes this problem and should be installed on any IBM WVS V5.1 server running applications developed using Avaya IVR Designer. As an alternative, the application developer can edit the resulting TAS application to remove all the say " " requests and then recompile the application.
Using this feature
Administer MRCP ASR using Web Administration (Feature Packages > Speech and DPR Administration > Administration) or the speech and sproxyadm commands.
Administer MRCP TTS using the Text-to-Speech Configuration screen and the Assign Text-to-Speech Server screen in Web Administration or the tts command.
