Lexxa,
I don't have a link to an all-incvlusive document, but I can try and answer your questions here.
1) CCM software ( Media Streaming App)
2) IOS software
3) IOS hardware
Technically, you forgot Transcoders. They essentially serve a different function than an IOS hardware MTP.
CM Software MTP- Only supports g.711ulaw streams.
IOS Software MTP- Codec has to be the same on both sides. Does not use DSPs. Can be used for RTP-NTE to other OOB DTMF conversions. Supports T.38 passthru. Cannot pass NSE-based switchovers. This is what most people end up using for MTPs in a SIP trunk design.
IOS Hardware MTP- Codec has to be the same on both sides. Uses DSPs. Does everything the software MTP can do, but is typically used when the media needs to be re-packetized.
IOS Transcoder- Main function is to allow for different codecs to talk to each other. Codec needs to be g.711ulaw on one side to any codec on the other side. Can re-packetize, and also peek in the audio stream to insert/pull-out DTMF embedded in the audio stream payload.
I have some clients who use SIP trunk (w req. MTP) from CUCM to Service Provider and MGCP controlled FXS ports
hint: Service provider uses NON CISCO equpment, and for some reasons client doesn't use CUBE!
I can't speak on the specifics of your environment, but if you configure early-offer forced and mid-call signaling pass-thru on a SIP to SIP CUBE, you typically can do calls to almost all SIP providers without needing an MTP required for the call flow.
thera are a lot of problems with fax & modems.
I
do some tests and get a some positive results only when switched off
all fax/modem feature t.38/fax-pass/modem-pass and use g711 codec.
standard t.38 won't work
It is unclear what you are getting at here. First, you need to be clear if the provider supports t.38 or not. If they don't support T.38, your best bet is to nail up a g.711 call to the provider, and you'll get best-effort faxing which should be fine at low speeds. High speed fax and modems would be sketchy at best across a g.711 call in voice mode. You can use specific device pools/regions/dial-peers to acheive this such that calls from/to the fax numbers always are g711 from the start of the call.
Keep in mind that if you are doing any switchovers via NSE (gw-controlled MGCP, SCCP, or nse-forced) then make sure you aren't invoking the MTP, as MTPs don't pass NSEs properly out the other side. Modem passthrough is Cisco proprietary, so you'll never get that to work with a non-Cisco equipped SP. Furthermore, modem passthrough requires an NSE based switchover, which isn't going to work with the MTP as noted above.
You can invoke an MTP for a T.38 call, as long as 'codec pass-thru' is specified. Obviously, your provider needs to support T.38, though. You need to ensure that you use protocol-based switchovers for this (CA-controlled with MGCP, or via H.323 RM/SIP Re-INVITE messaging.)
Fax pass-through switchover is essentially just an upspeed to g711ulaw once the call is established via the call-control protocol messaging, so you can do this with an MTP.
Whether you are doing SIP or H.323, capabilities are the same on the MTP from a functional perspective, since the MTP is really only speaking SCCP anyway.
As far as DTMF-relay goes, the only thing relevant to talk about is RTP-NTE and in-band audio. All other types of DTMF-relay follow the signaling path, and are irrelevant from the perspective of an MTP (which terminates media). If you need to convert DTMF to-from in-band audio, you need a transcoder. Converting RTP-NTE to another type of DTMF-relay (H245-alpha/signal, SIP notify, etc.) can be done with a software or hardware MTP, as well as a transcoder.
Hope this helps. If you can be more specific about your SIP provider's requirements and what you are trying to fax from, we can get into more specific design.
