What is needed to support VoIP with Blueworx Voice Response

Using DTNA, multiple Blueworx Voice Response LPARs are supported. An appropriate allocation of CPU, memory, storage and Ethernet resources must be assigned to each Blueworx Voice Response LPAR. As a guideline, a system performance rPerf of 20 can support a 480-channel Blueworx Voice Response LPAR running speech-enabled VoiceXML applications. See http://www.ibm.com/systems/power/hardware/notices/rperf.html for further information on rPerf.

The use of secure SIP and secure RTP, increases the system performance requirements of Blueworx Voice Response by approximately 30%. As a guideline, a system performance rPerf of 26 can support a 480-channel secure SIP and secure RTP Blueworx Voice Response LPAR running speech-enabled VoiceXML applications.

Unless your system has built-in Ethernet, to use SIP signaling, you will need an Ethernet adapter installed and configured for use with AIX. See your AIX manuals for instructions. You can then connect to your IP network to use it for SIP signaling using the Ethernet port on the installed card or at the back of the pSeries computer. See Blueworx Voice Response for AIX: Installation for more information on connecting Blueworx Voice Response to the network.

Note that you can choose to use separate Ethernet adapters for SIP and voice (RTP) communication, or a separate Ethernet adapter for both SIP and voice (RTP) communication.

Capacity planning for VoIP systems using DTNA involves considerations about the use of DTMF detection and voice compression:

DTMF detection

With DTNA, the system unit's processors are used for DTMF detection. This cost can be avoided if the VoIP network supplies DTMF send/receive keys using RTP payload packets - RFC2833 (Telephone Event).

Compression

For compressed voice (playing and/or recording)

The DTNA adapter software needs to do a decompression on play and a compression on record. This can take a significant processing effort.

iLBC compression is significantly more complex than G.711 and so, understandably, requires greater processing power. A system that can currently support 480 channels of G.711 can typically support up to 120 iLBC channels. Systems with a higher/lower rPerf will support more/less concurrent channels, respectively, up to the maximum 480 per system/partition. See http://www.ibm.com/systems/power/hardware/notices/rperf.html for further information on rPerf.

For uncompressed voice (playing and/or recording)

No decompression and subsequent compression is required, so the CPU load for DTNA processing is reduced.

DTNA adapters provide the following functionality:

• Implement RTP for transmission and reception of voice packets on up to 120 channels at the same time.
• Provide the interface for all channels to the Ethernet in the system unit for DTNA.