The Local Transcoding Interface (LTI) was a Cisco Unified Border Element (CUBE) transcoding feature originally introduced on Aggregation Services Routers (ASR) platform in 15.1(1)S. Starting with CUBE 9.0, this feature was added to ISR G2 platforms with additional enhancements. LTI includes an internal API to access digital signal processor (DSP) resources. This API bypasses the need for CME configuration and licensing, as well as the use of Skinny Client Control Protocol (SCCP). When both LTI-based and SCCP-based transcoding are configured, LTI takes precedence.
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Local Transcoding Interface (LTI)
The information in this document is based on Cisco Unified Border Element (CUBE) 9.0.
Refer to Cisco Technical Tips Conventions for more information on document conventions.
|CME/SCCP-based Transcoding||LTI-based Transcoding|
|SCCP protocol is used for controlling DSP resources used for transcoding.||Internal API are used to access DSP resources for transcoding.|
|Transcoding resources (DSPFARM) and CUBE can be on different platforms.||Transcoding resources (DSPFARM) and CUBE need to be on the same platform.|
|SCCP client (SCCP CCM...) configuration and SCCP server (telephony service) configuration is required for CUBE-Ent configuration apart from DSPFARM profile configuration.||Only DSPFARM profile configuration is required. SCCP configuration and CUCME configuration is not required when used with CUBE-Ent.|
|DSPFARM registers with CUCME over TCP socket using SCCP.||No TCP socket is opened and no registration is used.|
DSPFARM profile is associated to SCCP using CLI.
dspfarm profile <tag> transcode associate application sccp
SSPFARM profile is associated to a new application type
dspfarm profile <tag> transcode associate application cube
|High density transcoding needs to be enabled through CLI for higher performance. High density transcoding will be flow around through the transcoder.||Inherently high density and always flow through. Matches performance of high density transcoding. All flow through features are supported on transcoding calls.|
|SRTP –RTP using transcoder requires crypto PKI trustpoint configuration to establish the TLS connection with SCCP server.||Crypto PKI trustpoint configuration is not required for SRTP-RTP calls.|
! Enable CUBE voice service voip allow-connections sip to sip allow-connections h323 to h323 allow-connections h323 to sip allow-connections sip to h323 !--- This example shows a dspfarm profile configuration with the associated application CUBE for LTI transcoding. codec g729ar8 codec g729br8 codec g711alaw codec g711ulaw codec g729r8 maximum sessions 12 associate application CUBE !--- Only Dspfarm profile configurations are needed for LTI based transcoding. All the sccp based transcoding features will be supported with LTI based transcoding.
CUBE#show dspfarm profile 1 Dspfarm Profile Configuration Profile ID = 1, Service =Universal TRANSCODING, Resource ID = 1 Profile Description : Profile Service Mode : Non Secure Profile Admin State : UP !--- Profile 1 is ACTIVE Profile Operation State : ACTIVE !--- Profile 1 (LTI) is associated with CUBE application Application : CUBE Status : ASSOCIATED Resource Provider : FLEX_DSPRM Status : UP Number of Resource Configured : 12 Number of Resources Out of Service : 0 Number of Resources Active : 0 Codec Configuration: num_of_codecs:5 Codec : g729ar8, Maximum Packetization Period : 60 Codec : g729br8, Maximum Packetization Period : 60 Codec : g711alaw, Maximum Packetization Period : 30 Codec : g711ulaw, Maximum Packetization Period : 30 Codec : g729r8, Maximum Packetization Period : 60
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Refer to Cisco Technical Tips Conventions for information on conventions used in this document.