I can't seem to remember the advantages and disadvantages of MTP. What's the call flow like?
Media Termination Points extend supplementary services, such as call hold, call transfer, call park, and conferencing, that are otherwise not available when a call is routed to an H.323 endpoint. Some H.323 gateways may require that calls use an MTP to enable supplementary call services, but normally, Cisco IOS gateways do not.
The Cisco IP Voice Media Streaming Application MTP accepts two full-duplex G.711 Coder-Decoder (CODEC) stream connections. MTPs bridge the media streams between two connections. The streaming data that is received from the input stream on one connection passes to the output stream on the other connection and vice versa. In addition, the MTP trancodes a-law to mu-law (and vice versa) and adjusts packet sizes as required by the two connections.
Each MTP belongs to a device pool, which specifies, in priority order, the list of Cisco Unified Communications Managers to which the devices that are members of the device pool should attempt to register. This list represents a Cisco Unified Communications Manager group. The first Cisco Unified Communications Manager in the list specifies a device primary Cisco Unified Communications Manager.
An MTP device always registers with its primary Cisco Unified Communications Manager if that Cisco Unified Communications Manager is available and informs the Cisco Unified Communications Manager about how many MTP resources it supports. The Cisco Unified Communications Manager controls MTP resources. You can register multiple MTPs with the same Cisco Unified Communications Manager. When more than one MTP is registered with a given Cisco Unified Communications Manager, that Cisco Unified Communications Manager controls the set of resources for each MTP. You can also distribute the MTPs across a networked system as desired.
For example, consider MTP server 1 as configured for 48 MTP resources, and the MTP server 2 as configured for 24 resources. If both MTPs register with the same Cisco Unified Communications Manager, that Cisco Unified Communications Manager maintains both sets of resources for a total of 72 registered MTP resources.
When the Cisco Unified Communications Manager determines that a call endpoint requires an MTP, it allocates an MTP resource from the MTP that has the least active streams. That MTP resource gets inserted into the call on behalf of the endpoint. MTP resource use remains invisible to both the users of the system and to the endpoint on whose behalf it was inserted. If an MTP resource is not available when it is needed, the call connects without using an MTP resource, and that call does not have supplementary services.
Make sure that the Cisco IP Voice Media Streaming application is activated and running on the server on which the MTP device is configured.
The Cisco IP Voice Media Streaming application, which is common to the MTP, Conference Bridge, annunciator, and Music On Hold applications, runs as a CM service.
You can add an MTP device in two ways:
•
You automatically add an MTP device when you activate the Cisco IP Voice Media Streaming Application service from Cisco Unified Serviceability.
•You can manually install the Cisco IP Voice Media Streaming Application on a networked server and configure an MTP device on that server through Cisco Unified Communications Manager Administration.
Not all call flows require an MTP. Do have DTMF problems? DTMF Mismatches etc?
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/6_0_1/ccmsys/a05mtp.html#wp1030050
