Mitel MiVOICE BUSINESS, Engineering Manualline

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Bandwidth, Codecs and Compression
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the two phones stream directly within the LAN. This call could also be blocked if there are
insufficient IP trunk sessions or channels allocated.
• A controller can have a maximum of 999 compression zones.
More details on zones and setup can be found in the Technician’s Handbook and the installation
documentation.
IP TRUNK ROUTES AND COMPRESSION
The IP trunk route is a virtual path from one 3300 ICP to another 3300 ICP. One of the parameters
assigned to this route is compression. Assuming that the end devices are capable of
compression, compression is enabled on the route, and there are sufficient available channels,
or sessions, then the end devices stream using compression. Otherwise the call is blocked,
rerouted, or streamed with G.711 (uncompressed).
See “Network Configuration Concepts” on page 195 for more details on bandwidth requirements
for different LAN and WAN links with and without compression.
IP NETWORKING AND COMPRESSION LICENSES
Compression and available bandwidth affect voice quality. Compression sessions and IP
networking require licenses. Setting different compression zones and assigning different IP
phones to the different zones determines when to use compression licenses. The IP networking
license determines whether calls can be routed between units over its IP infrastructure, and
how many of the sessions are allowed over a particular connection between different controllers.
Compression and IP networking work together, but can also be used independently.
From a voice quality view, if the number of calls requiring compression exceeds the number of
licenses, a call does not fail, but it is not compressed. It will use more bandwidth than expected.
The section “Bandwidth Requirements” on page 210 discusses bandwidth calculations. If IP
trunks are used, the number of concurrent sessions can also be defined; see the section “IP
networking limit working example” on page 227.
COMPRESSION AND LICENSES
Some guidelines for compression licenses and connections in IP:
• An IP phone-to-IP phone connection does not use a compression license in the 3300 ICP
when the call is connected by an IP trunk over a WAN.
• An IP phone (node A) to TDM phone (node B) call uses an E2T compression license on
node B only when the call is connected by an IP trunk over a WAN and the call is compressed
across the IP trunk.
• A TDM phone (node A) to TDM phone (node B) call uses an E2T compression license on
both nodes A and B when the call is connected by an IP trunk over a WAN and the call is
compressed across the IP trunk.
• Conference calls use one compression license for each IP connection in the conference
that would normally require a compression license when connected to a TDM device.