Транскодинг на ССМ + cisco 2811 + SIP провайдер

Core Issue

In a call-processing environment that uses Session Initiation Protocol (SIP), use SIP trunks in order to configure a signaling interface with Cisco CallManager for SIP calls. SIP trunks, or signaling interfaces, connect Cisco CallManager clusters with a SIP proxy server. A SIP signaling interface uses port-based routing, and Cisco CallManager accepts calls from any gateway as long as the SIP messages arrive on the port that is configured as a SIP signaling interface. The SIP signaling interface uses requests and responses in order to establish, maintain, and terminate calls between two or more endpoints.

In order to choose this method, go to Device > Trunk and choose SIP Trunk in the Cisco CallManager Administration.

Also, configure route groups and route patterns that use the SIP trunks to route the SIP calls.

Refer to Understanding Session Initiation Protocol (SIP) for more information about SIP and how to configure SIP trunks.

Resolution

Telco only supports G711U In-band Voice DTMF, and the Cisco CallManager SIP trunk only supports RFC 2833 RTP-NTE DTMF.

Use the Cisco Multiservice IP-to-IP Gateway (IPIPGW) and transcoder to transcode the RFC2833 RTP-NTE digits into In-band Voice G711U DTMF digits:

1. Upgrade to Cisco IOS® 12.4(6)XE in order to enable the DTMF transcoding feature.
2. Configure the dial-peer for Cisco CallManager in this way:

   dial-peer voice voip
   preference 1
   destination-pattern [1-8]T
   session protocol sipv2
   session target ipv4:x.x.x.x
   dtmf-relay rtp-nte
   codec g711ulaw
   no vad

3. Configure the dial-peer for the SIP VoIP provider in this way:

   dial-peer voice voip
   description Outbound dial-peer
   translation-profile outgoing strip9
   destination-pattern 9T
   session protocol sipv2
   session target ipv4:y.y.y.y.
   codec g711ulaw
   no vad

4. Configure the transcoder to register to the IPIPGW as:

   sccp local GigabitEthernet0/0
   sccp ccm identifier 1 version
   sccp
   !
   sccp ccm group 1
   associate ccm 1 priority 1
   associate profile 1 register MTP001795e45a80
   !
   dspfarm profile 1 transcode
   codec g711ulaw
   codec g711alaw
   codec g729ar8
   codec g729abr8
   codec gsmfr
   maximum sessions 20
   associate application SCCP

Once these steps are complete, the IPIPGW transcoder starts to transcode the DTMF digits.

Refer to Understanding Session Initiation Protocol (SIP) and Understanding Cisco CallManager Trunk Types for more information on this.