MTP or transcode. What is the difference

[gene]

When do you use MTP and when transcoders. I notice ccm has some MTP built in and no transcoders. I am having some issues with calls not able to be transfered and seeing errors in the event log about mtp resources not being avalible. How many MTP resources does CCM provide? How can you tell what state they are in and if you need more? I also have a dsp farm with 30 transcoding resources. Are these usable as MTP as well or are the for another purpose.

[thisisshanky]

Gene,

Transcoders are MTP's but on hardware. These can do g711, g729 conversion as well in hardware (use DSPs).

CCM has a built in MTP which is capable of only g711.

Typically a software based MTP is invoked for H323 based devices (trunks, gateways, h323 phones etc). The default setting for Software MTP is 48 resources. If you are having transfer issues over a h323 trunk, you typically have to check the MTP required option to allow supplementary services such as hold, transfer etc.

HTH

Saknar

PS: please remember to rate posts!

[khchiang]

Dear Saknar,

May I know that how to configure the MTP on c3845 MGCP gatway with CCM 5.0

thanks for your advise

KH

[thisisshanky]

You would typically configure a transcoder (on HW) on a 3845 gateway. You need to make sure you have enough DSP resources available to do the transcoding portion since you are hosting the transcoder and your t1s on the same gateway.

here are some good links.

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a008037e2df.html

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a008037e9b4.html#wp24227

If you are using NM-HDV then the following configs apply:

voice-card 1

dsp services dspfarm

dspfarm transcoder maximum sessions 4

dspfarm

sccp local FastEthernet0/0

sccp

sccp ccm priority 1

sccp ccm priority 2

For NM-HDV2 with PVDM2 or onboard PVDM2, the following configs apply:

voice-card 0

dspfarm

dsp services dspfarm

sccp local FastEthernet0/0

sccp ccm identifier 2

sccp ccm identifier 1

sccp

!

sccp ccm group 1

associate ccm 1 priority 1

associate ccm 2 priority 2

associate profile 1 register MTP0015f956d2d8

!

dspfarm profile 1 transcode

codec g711ulaw

codec g711alaw

codec g729ar8

codec g729abr8

codec gsmfr

codec g729r8

codec g729br8

maximum sessions 18

associate application SCCP

HTH

Sankar

PS: please remember to rate posts!

[Kane_CCIE]

Hi Sankar,

I am having similar issues. On an inbound call from a H323 gatekeeper controlled trunk, the CallManager doesn't invoke an MTP, only a transcoder. This doesn't allow me to use supplementary services on the IP phone. I cannot hear the PSTN if I hold and then resume but they can hear me. Because of design constraints, I need to use G729 on the IP phone but G711 on the gateway so I would like to use an MTP and a transcoder. Everything is OK on an oubound call but an inbound call does not invoke an MTP, only a transcoder. I'm using regions to specify the codecs to be used.

Please advise.