To assemble a
Blueworx Voice Response system
that supports VoIP, you will need one of the three following configurations:
- BladeCenter using
DTNA
-
- An Blueworx BladeCenter computer
with AIX PowerPC® blades (JS20, JS21, JS22, PS700,
PS701, or PS702).
- AIX 6.1 or 7.1 installed.
- Blueworx Voice Response software,
Version Version 7.
- System p using DTNA
-
- An Blueworx System p with Power 5, Power 6, or Power 7 processors.
- AIX 6.1 or 7.1 installed on the system unit.
- Blueworx Voice Response software,
Version Version 7.
To send and receive voice data over an IP network
your Blueworx Voice Response system requires at
least one DTNA adapter. The DTNA is installed using a single AIX command
and then configured using Blueworx Voice Response Pack and/or System
configuration.
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
- As previously described, DTNA only supports uncompressed
voice over a Voice over IP link. However, the use of compressed voice
within the voice application (the 5:1 ‘GSM’ algorithm)
can have a big effect on the processor requirements for DTNA.
- 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.
- Perform ‘back-end processing’ for the Blueworx Voice Response Device
Driver in the same way as the DTTA (for more information
see Blueworx Voice Response for AIX:
Installation).
DTNAs (software adapters for VoIP) can be installed
in the same system as DTTAs. However, calls cannot be tromboned between
DTTAs and DTNAs, although they can be tromboned within each group
of similar adapters, as follows: DTNA to DTNA, DTTA to DTTA, but not DTNA
to DTTA or DTTA to DTNA.
Some example combinations of adapters are:
- One to four DTNAs - For a VoIP-only system for four,
eight, 12 or 16 ‘pure VoIP’ trunks.
- One DTNA, and one, two, or three DTTAs for a mixed VoIP/ PSTN
configuration.
- Two DTNAs , and two DTTAs for a mixed VoIP/ PSTN configuration.
The DTNA can be mixed with DTTAs, with a maximum of
four instances of either type.
Adapterless configurations have the following double-trunking
capabilities:
- Calls can be double-trunked between adapterless connections using
the Trombone Custom Server.
- Adapterless connections can coexist with DTTA in the same system
unit, allowing hybrid PSTN/VoIP configurations in, for example, IP
Call Centers. However, calls cannot be double-trunked between adapter
and adapterless connections.
- Adapterless DTNA VoIP/SIP connections cannot co-exist in the same
system with DTEA (hardware VoIP adapter) connections.