Specifications
MBG Engineering Guidelines, Release 8.0
The bandwidth figures for a single device are provided in Bandwidth Requirements for the Remote Site on page
19. For multiple devices, follow the procedure below.
Assumptions:
• Internet Service Providers specify bandwidth available to the user. i.e. PPPoE overhead does not need
to be included in the provisioning of DSL bandwidth, but IP overhead does need to be included.
• RTP Bandwidth Requirements are as follows:
◦ G.711 = 80 Kbps
◦ G.729 = 24 Kbps
◦ G.722.1 = 48 Kbps
• At 6 calls per hour Control stream bandwidth requirement is 20 Kbps peak for each 12 remote devices,
and 1 Kbps idle for each remote device.
• The calculation below does not include bandwidth required for features such as paging. If group paging
is enabled for teleworkers, an additional RTP stream should be provisioned for each remote member of
the paging group.
• Whenever possible, transcoding should be performed by the ICP rather than the Mitel Border Gateway,
as this typically provides improved voice quality.
If the mix of codecs in use cannot be reliably estimated, it is safest to assume G.711 for all calls.
Note: The actual bandwidth available will likely be less than the amount of bandwidth the ISP
advertises. Also, the amount of available bandwidth may fluctuate throughout the day based on usage
patterns of other subscribers.
The best way to determine the amount of available bandwidth is to use a speed test tool, preferably one
provided by a third party rather than the ISP themselves – buyer beware.
G.711 Calculation
Bandwidth = number of users * idle control stream requirement
+ number of calls * RTP requirement
+ number of users / 12 * peak control stream bandwidth
For the teleworker example of 20 remote users:
20 * 1 Kbps + 9 * 80 Kbps + 20/12 * 20 Kbps
= 773 Kbps
For the call center example of 1000 remote agents:
1000 * 1 Kbps + 583 * 80 Kbps + 1000/12 * 20 Kbps
= 49307 Kbps or 48.15 Mbps
G.729a Calculation
Bandwidth = number of users * idle control stream requirement
+ number of calls * RTP requirement
+ number of users / 12 * peak control stream bandwidth
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