SDP in H248 v/s Megaco

Hi,

Can someone help me with the following doubts in H.248?

1. As per my understanding ,in H.248, when the MG1 indicates to MGC (via off hook) that it wants to communicate to MG2, MGC sends an ADD Request to MG1. MG1 creates a context and Ephemereal TerminationID and allocates resources for the same. It sends this information (about media resources i.e. IP and port) to the MGC in SDP in its Local Descriptor. MGC conveys this information to MG2 via SDP’s Remote descriptor when it sends the ADD Request to MG2. MG2, in turn, allocates the resources and conveys its IP and port for communication in the ADD Reply’s SDP (Local Descriptor), which is then passed to MG1.So, whenever SDP is used to convey the connection information, it is done in the Local and Remote descriptors. 

Now the question is what is the use of tunneling SDP information in Signal and ObservedEvent Descriptor?
 
I have a large amount of network traffic, and in all the buffers, SDP information NEVER comes in Media descriptor’s local and remote. It always comes tunneled in Signal and ObservedEvent descriptors. So, can I somehow use this tunneled SDP information instead of local and remote descriptors? 

2. As per the protocol, every ADD request from MGC to MG should contain two ADD commands: 
(i)	Create a context and ADD a well-defined physical termination to it. 
(ii)	Create an Ephemereal Termination, allocate IP and port and add it to the context created in (i).
   According to this, every buffer containing ADD request must have two ADD commands. However, in H.248 traffic, I have observed that the request to add physical termination is not present along with the request for creating an ephemereal termination. Can someone explain the reason why this could be happening?

3. In H.248, NOTIFY request should be sent to the physical Termination. However, in the buffers I have, NOTIFY request is sent on the Ephemereal termination. 

In MEGACO’s traffic, I have observed that:
(i)	ADD Request always contains two commands: to add physical termination and to create andadd epemereal termination.
(ii)	NOTIFY is received on the physical termination.

Then, why doesn’t the H.248 traffic conform to the requirements mentioned in the protocol?



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