Re: TDMPW and MeGaCo/SDP

Hi Albrecht, Christian and all,


> /To H.248 Media Descriptor for IP bearer:/
>
>    *
>       /your proposal would be insufficient, Y.1453 defines not a
>       single, but multiple possible modes of TDMoIP interworking! /
>    *
>       /See § 7.2/Y.1453 concerning information elements for TDMoIP
>       control (=> ´correspondent SDP must be defined if the Y.1453
>       provisioning approach would be replaced by an SDP-based
>       signalling approach (for TDMoIP IWFs embedded in H.248 MGs or
>       SIP VoiceGateways)./
>

That's right, but we must take into account that TDMPW parameters may be 
negotiate by the PW control plane.

So, I think it could be enough that MGC, by MeGaCo/SDP, indicates to the 
MG that it must use a TDMPW "codec" and the address of the other PW edge.

c=IN IP4 333.333.1.1
m=audio <port> RTP/AVP <Dynamic_PT>
a=rtpmap:<Dynamic_PT> TDMoIP/8000

> /
> /To H.248 Media Descriptor for TDM bearer:/
>
>    *
>       /the MUX approach is just an option!/
>    *
>       /alternatives, e.g., the "the group-and-member scheme (addrtype
>       is "GRP")" as proposed by Tom in his SDP-TDM draft
>       (http://www.watersprings.org/pub/id/draft-taylor-mmusic-sdp-tdm-01.txt)/
>
> /
> //
> //
>
>     ------------------------------------------------------------------------
>     *From:* Javi Muñoz [mailto:[email protected]]
>     *Sent:* Dienstag, 1. Februar 2011 14:07
>     *To:* [email protected]
>     *Subject:* Re: [Megaco] TDMPW and MeGaCo/SDP
>
>     H.248 MUX termination (N x B channels) is a good choice at ISDN
>     termination.
>
>     But, at IP side, we still need to describe TDMoIP in SDP. For
>     instance, we may propose any like this:
>
>     m=audio <puerto> RTP/AVP <PT_dinámico>
>     a=rtpmap:<PT_dinámico> TDMoIP/8000
>
>
>
>
>
>     El 31/01/2011 16:54, Schwarz, Albrecht (Albrecht) escribió:
>>     /Just some high-level indications:/
>>     //
>>     /Multirate means effectively N-out-of-K (with K = 24 or 30
>>     dependent on ANSI /ETSI markets; and 1 < N <= K)./
>>     /That's a first requirement./
>>     /Secondly, the selection of channels may be random, they must not
>>     be in consecutive order (e.g., think about the permutations for N
>>     = 5)./
>>     /Thirdly, there could be a dependency of the choosen CESoIP
>>     emulation service to the H.248 connection model./
>>     //
>>     /Possible solution: H.248 MUX termination ... at the high-level .../
>>     //
>>
>>         ------------------------------------------------------------------------
>>         *From:* Javi [mailto:[email protected]]
>>         *Sent:* Montag, 31. Januar 2011 11:47
>>         *To:* [email protected]
>>         *Subject:* Re: [Megaco] TDMPW and MeGaCo/SDP
>>
>>         I agree, TDMoIP is an option only.
>>
>>         But, if it is used, MGC would use SDP at Local/Remote MeGaCo
>>         descriptors. How may be that SDP description for TDMoIP?
>>
>>>         However, there was never any H.248 Profile standardized with
>>>         /*multirate*/ support, at least to my knowledge.
>>>         (I'm aware of vendor specific profile, but that are
>>>         proprietary solutions.)
>>>
>>
>>         I would be interested to know any of that proprietary
>>         solutions. May you indicate me any?
>>
>>>
>>>         __
>>>         /*Y.2262 PSTN/ISDN emulation and simulation, Appendix IV
>>>         Examples of emulation of PSTN and N-ISDN bearer services
>>>         *(This appendix does not form an integral part of this
>>>         Recommendation)
>>>
>>>         Examples for the emulation of PSTN and N-ISDN bearer
>>>         services are provided:
>>>
>>>         1) Monorate bearer services (= 1 × 64-kbit/s digital bearer
>>>         in PSTN/ISDN)
>>>         . ITU-T Recommendations I.231.2 and I.231.3 may be emulated
>>>         by a single RTP
>>>         session, with or without RTP control protocol (RTCP), using
>>>         an RTP profile according
>>>         to IETF RFC 3551.
>>>         . ITU-T Recommendation I.231.1 may be emulated by a single
>>>         RTP session, with or
>>>         without RTCP, using RTP clearmode according to IETF RFC 4040.
>>>
>>>         2) Multirate bearer services (= N × 64-kbit/s digital bearer
>>>         in PSTN/ISDN; N greater than one)
>>>         . ITU-T Recommendations I.231.4 to I.231.10 may be emulated
>>>         by TDMoIP described
>>>         in ITU-T Recommendation Y.1453.
>>>
>>>         /
>>>         > -----Original Message-----
>>>         > From: [email protected]
>>>         > [mailto:[email protected]] On Behalf Of Javi
>>>         > Sent: Samstag, 29. Januar 2011 02:13
>>>         > To: [email protected]
>>>         > Subject: [Megaco] TDMPW and MeGaCo/SDP
>>>         >
>>>         > Assuming the next situation:
>>>         >
>>>         > ISDN Terminal 1  -   MG1 -  [IP network] -  MG2   -   ISDN
>>>         Terminal 2
>>>         >
>>>         > where the MGs (Media Gateway) are controlled by a MGC
>>>         (Media Gateway
>>>         > Controller) via MeGaCo[H.248.1].
>>>         >
>>>         > [ITU-T Y.2262 / Annex IV] proposses that MGs may transport
>>>         > ISDN B-channels over the IP network:
>>>         >
>>>         > + By a single RTP session (when monochannels ISDN services)
>>>         >
>>>         > + Or by TDMoIP (= UDP TDMPWs), when multichannels ISDN
>>>         services.
>>>         >
>>>         >
>>>         > How may MGC indicate to the MG that it uses PWs at the IP
>>>         termination?
>>>         >
>>>         > It may be done by MeGaCo, using SDP[RFC4566] at Local/Remote
>>>         > descriptors. However, how may be that SDP description of
>>>         TDMPWs?
>>>         >
>>>         > Thanks,
>>>         >
>>>         > Javier Muñoz
>>>         >
>>>         >
>>>         > _______________________________________________
>>>         > Megaco mailing list
>>>         > [email protected]
>>>         > https://www.ietf.org/mailman/listinfo/megaco
>>>         >
>>
>

_______________________________________________
Megaco mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/megaco