IOS Enhanced MTP/XCODE question

[jordan.bean]

We just added a Cisco 2851 with 5 PVDM2-48's to our network.  I have both hardware MTP and XCODE configured and registered to CUCM 6.1.  We have a SIP trunk configured in CUCM that is set to "Use MTP".  I'm noticing that a 'show dspfarm dsp active' on the 2851 shows that XCODE sessions are active, but I have not seen any MTP sessions active.  I can see from a 'show sccp connections" that the XCODE's are xcoding g729b <-> g711 streams.

My question is how MTP and XCODE functions operate.  If a g729 stream needs to connect to the SIP trunk via g711, will only an XCODE be invoked and no MTP?  If both endpoints are g711, will MTP be invoked and no XCODE?

[rfallara]

XCODE will be used when you are going from one codec to another while MTP is more

for services that are not nativley supported on the gateway/trunk protcol (i.e. you put a call on hold but your h323 gateway needs somewhere to land that call while on hold). XCODE is very processor intensive which is why it has to run on hardware, MTP points are more of a logical device which is why it can run in software on your call managers. From my experience MTP points are generally not that heavily untilized but Xcode can be if you have nodes on your net that do not support the more complex voice codecs.

HTH

Ron

[Felipe Garrido]

A transcoding resource will act as an MTP if the call legs require different codecs. An MTP should be invoked when the call legs use the same codec.

For more info,

http://www.cisco.com/en/US/docs/voice_ip_comm/cucmbe/admin/7_1_2/ccmsys/a05trans.html#wp1022917

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/media.html