Specifications

Chapter 9 Catalyst DSP Provisioning
Catalyst MTP Transcoding Services
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Cisco IP Telephony Network Design Guide
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The following list gives intercluster MTP/Transcoding details:
• If transcoding is required between Cisco CallManager clusters, the H.323
Intercluster trunk must be configured with an MTP resource.
• All calls between Cisco CallManager clusters will go through MTPs.
• Outbound Intercluster calls will use an MTP/Transcoding resource from the
Cisco CallManager from which the call originates.
• Inbound Intercluster call will use the MTP/Resource from the
Cisco CallManager terminating the inbound Intercluster trunk.
• Additional DSP MTP/Transcoding resources should be allocated to
Cisco CallManagers terminating H.323 Intercluster trunks
MTP Transcoding Caveats
The following summary caveats apply to Catalyst MTP transcoding:
• Catalyst MTP transcoding service only support LBR codec-to-G.711
conversion, and vice versa. There is no support for LBR-to-LBR codec
conversion.
• On the Catalyst 6000, transcoding services cannot cross port boundaries.
• Each Cisco CallManager must have its own MTP transcoding resource
configured.
• If transcoding is required between Cisco CallManager clusters, the H.323
Intercluster trunk must be configured with an MTP resource. All calls
between Cisco CallManager clusters will go through the MTPs.
• If all n MTP transcoding sessions are utilized, and an n + 1 connection is
attempted, the next call will be completed without using the MTP transcoding
resource. If this call attempted to use the software MTP function to provide
supplementary services, the call would connect, but any attempt to use
supplementary services would fail and could result in call disconnection. If
the call attempted to use the transcoding features, the call would connect
directly, but no audio would be heard.
See Table 9-1 for a list of transcoding capabilities for each module.