DSP Channel Resources for Transcoding

In addition to DSP resources (channels) required for PRI trunk interfaces, the device provides flexibility in providing additional DSP resources for SBC functionality (such as transcoding). This is achieved by the following:

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Obtaining DSP resources from the Media Processing Module (MPM)

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"Borrowing" DSP resources from PRI interfaces

To support these capabilities and to allow optimal management of the required DSP resources, you need to ensure suitable hardware and software configuration, as described below:

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Hardware Configuration: The device can obtain DSP resources using one of the following hardware configurations:

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MPM Modules: MPM modules provide additional DSP resources for the SBC application and/or IP media functionality such as detection (e.g., Answer Machine Detection). The device can house up to four MPM modules. When the MPM modules are installed in chassis slots #2, #3, #4, and #5, the device supports up to 192 DSP resources (i.e., 96 transcoding sessions), where each module provides up to 48 DSP resources.

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PRI Modules: DSP resources can be obtained from installed PRI modules. When this occurs, some trunk span interfaces are "disabled" due to unavailable DSPs.

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Combination of MPM and PRI Modules: DSP resources can be obtained from both MPM and PRI modules. For example, to achieve 140 channels (with IP media features), you need to use two MPM modules (installed in slots #4 and #5) and one PRI module providing two PRI spans (installed in Slot #1).

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Software Configuration:

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Configure the [MediaChannels] parameter to the maximum number of required IP media channels, regardless of the module from where the channels are obtained.

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Configure the [IPmediaChannels] parameter to the number of DSP channels that you want to “borrow” (use) from each PRI module. The setting below shows an example of borrowing DSP channels from PRI modules #1 and #2:

[IPMediaChannels]
FORMAT Index = ModuleID, DSPChannelsReserved;
IPMediaChannels 1 = 1, 15;
IPMediaChannels 2 = 2, 10;
[\IPMediaChannels]