Alcatel 060170-10, User Manual, Page: 327 / 430

VoIP Commands
Page 5-185
Command Usage
Specify preferred coding profile voice packet interval (VPI) size and voice information field
(VIF) size.
Syntax Options
Remarks
This command is used to set the size of the voice information field (VIF), in bits, for a coding
profile. The VIF size is derived from the specified voice packet interval and the voice coding
algorithm. The voice coding algorithm must be specified before the desired voice packet
interval.
Each codec type uses a different mathematical algorithm (method) to encode/decode voice
(audio) data into IP packets. Any sound that is not a fax, modem, data or signaling tone
frequency, including music, is considered voice.
The data or PCM stream coming into the voice channel is referred to as the voice packet
interval (VPI) time of the packets coming into the voice channel. The encoder samples the
voice traffic every 10 milliseconds, i.e., it determines how many milliseconds of a sample to
take, e.g., 10 = 100 ms.
The codec puts the voice data into packet data form using this formula: 10 ms of data is
converted into one data packet. The size of the converted packet is the voice information
field (VFI) size, and what is ultimately sent over the IP network. The greater the VPI time the
larger the VIF packet and the quantity of data transmitted onto the network; however, when
the VPI time is shorter, more VIF packets are sent. In other words, the larger the VIF packets
the better the quality, but the greater the traffic and use of bandwidth.
voice coding profile voice packet interval
voice coding profile <
“codingProfName”
> voice packet interval <
packet_size
>
Definitions:
codingProfName Identifies coding profile by name, (e.g.,
salemprof1
); maximum length of 40 characters.
The following characters are permitted in the coding profile name: a-z, A-Z, 0-9, space and
# * ~ ’ ‘ ; : , .@ $ % ^ _ & | / \ < > ( ) [ ] { }
packet_size
Specifies voice packet interval in 10 millisecond increments. Supported values include
10, 20, 30, 40, 50, 60, 70, and 80.
Default:
The default packet size is
60
.
Command Example:
voice coding profile salemprof1 voice packet interval 10
voice coding profile calabprof2 voice packet interval 60