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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 the MRCP feature
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 communication between interactive voice response systems like Avaya IR and specialized speech engines (including but not limited to those that support ASR and TTS functionality).
In Avaya IR R2.0, MRCP ASR and TTS proxy servers (which are installed using the MRCP ASR package and MRCP TTS package on the Avaya IR system) extend support to ASR and TTS engines of Scansoft and Nuance using the MRCP protocol. This support is in addition to IBM WebSphere Voice Server (WVS) for Multiplatforms V5.1 already supported, since Release 1.2.1 or later. The vendor ASR and TTS engines are installed on a server, separate from the Avaya IR system. Vendor ASR and TTS engines can be installed on media servers that are used to implement the MRCP protocol or they can be installed on completely different servers.
The media servers that are used to implement MRCP open standard protocol include Scansoft SpeechWorks Media Server (Release 3.1.5 or later), Nuance MRCP Server (Release 1.0.0 SP 9 or later), and IBM WVS for Multiplatforms V5.1 (Release 5.1.3 or later). This expands the range of vendor options to those deploying voice response applications and systems. For information about Scansoft, Nuance, and IBM WVS for Multiplatforms V5.1, see Third-party product documentation.
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, http://ietfreport.isoc.org/old-ids/draft-shanmugham-mrcp-04.txt ).
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 neither sends, 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 responding 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 incompatibilities
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). For more information see MRCP ASR package, Speech Proxy SR - Speech Recognition package, MRCP TTS package, and Proxy Text-to-Speech package.
Once the MRCP package is installed and configured, it can integrate with vendor ASR and/or TTS engines supporting MRCP that are installed on a separate server. In Avaya IR Release 2.0, MRCP package on the Avaya IR system extends support to ASR and TTS engines of Scansoft and Nuance using the MRCP protocol. This support is in addition to IBM WebSphere Voice Server (WVS) for Multiplatforms V5.1 already supported, since Release 1.2.1. For information about Scansoft, Nuance, and IBM WVS for Multiplatforms V5.1, see Third-party product documentation.
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.
In Avaya IR Release 2.0, MRCP package on the Avaya IR system extends support to ASR and TTS engines of Scansoft and Nuance. Avaya IR with MRCP, also 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:
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 Web Administration (Feature Packages > Speech and DPR Administration >Administration > Text-to-Speech Configuration ) or the tts command.
