Specifications

Engineering Guidelines
182
• Network Zone Topology - Bandwidth Limits
• ARS Routes - Compression On/Off/Auto. Compression 'On' may override zone settings
(Auto setting is recommended)
The endpoint CODEC to use is also influenced by:
Can the end device support this CODEC? (Not all phones will support G.722.1, and some earlier
phone models may not support G.729. See phone details)
• Can the CODEC frame rate fit with the packet rate specified
• The MiVoice Business/3300ICP system can negotiate different CODEC types, but can only
terminate calls in G.711 or G.729, e.g. when used as a PSTN or TDM gateway. The same
applies to services for conference, MOH, Paging, Voice Mail, RADs, etc. that originate or
terminate on a MiVoice Business Multi-instance Media Server or 3300ICP
• Can the 3300ICP support the CODEC negotiation, e.g. MiVoice Business prior to Release
MCD 5.0 will not support wideband selection even if the phone supports the CODEC
• Is the end device SIP based, which can independently negotiate CODEC settings
Note that some SIP phones and SIP gateways may support G.722.1 (32kbits/s).
Low bit-rate CODECs send data as bursts of data, or Frames. The packet rate must be an
exact multiple of the frame rate in order to achieve a connection. The G.711 CODEC does not
use a Frame mechanism and is not part of this consideration.
• An ability to modify the CODEC selection is also provided within the MiVoice Business
node. This allows supported codec types to be added or removed from the node negotiation.
For example, the Administrator may wish to remove the G.729 CODEC so that only the
G.722.1 and G.711 CODECs can be negotiated. This functionality does not allow the G.711
codec to be removed as this is the base functionality required by all IP devices, including
other 3rd party products including SIP gateways and SIP phones. The methods used to
modify the CODEC selection are as follows:
• For software releases prior to MCD Release 5.0 SP2, the AddCodecFilter and Remove-
CodecFilter maintenance commands allowed the Administrator to specify which CODECS
would be offered for negotiation by devices at each end of a call within the MiVoice Business
network.
• For MCD Release 5.0 SP2 and greater, a new form called ‘Codec Settings’ allows the
Administrator to specify which CODECS would be offered for negotiation by devices at
each end of a call within the MiVoice Business network.
Table 57: Codec Frame Size and Packet Rates
Codec Frame Size Acceptable Packet Rates
G.729 10 ms 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 ms
G.722.1 20 ms 20, 40, 60, 80, 100 ms