Subject: [Megaco] Why separate Signaling Gateway from MGC?

From: "Patrick Lam" <[email-masked]>
Date: Sun, 9 Dec 2001 23:11:46 -0800

Hi:

I hope these will be the right groups to ask this question ..... :)

I have done some research on SS7 Signaling Gateways and MGCs.  I found an interesting similarities among most vendors:  the SG and MGC are usually separated into physically differen boxes.  While I understand that the scalability of the MGC might be the reason that the SS7 has to be separated from it, but I really want to know why the vendors can't combine the functionalities of SG and MGC together into one box?

Why not have the SG decode all the ISUP and do MGCP and H.323 all in one box?  What's the advantage of having a SG to convert SS7 to Sigtran, and then having MGC convert Sigtran to H.323 and do MGCP?

Thanks very much in advance,

Patrick.

---

From: "Tom-PT Taylor" <[email-masked]>
Date: Mon, 10 Dec 2001 12:09:26 -0500

The question should have gone to Sigtran rather than Megaco, but I'll answer
it.

The SG doesn't actually look at the call signalling: it does a transport
conversion for the layers beneath it.  Thus MTP3 becomes MxUA/SCTP/IP, Q.921
becomes IUA/SCTP/IP, and so on.  The signalling interworking is all done in
the MGC.

The other point is that these are functional roles, so vendors are free to
terminate the original transport directly on the box supporting the MGC
function where that makes sense. 

-----Original Message-----
From: Patrick Lam [mailto:[email-masked]]
Sent: Monday, December 10, 2001 12:12 AM
To: [email-masked]
Cc: [email-masked]
Subject: [Megaco] Why separate Signaling Gateway from MGC?

Hi:

I have done some research on SS7 Signaling Gateways and MGCs.  I found an
interesting similarities among most vendors:  the SG and MGC are usually
separated into physically differen boxes.  While I understand that the
scalability of the MGC might be the reason that the SS7 has to be separated
from it, but I really want to know why the vendors can't combine the
functionalities of SG and MGC together into one box?
 
Why not have the SG decode all the ISUP and do MGCP and H.323 all in one
box?  What's the advantage of having a SG to convert SS7 to Sigtran, and
then having MGC convert Sigtran to H.323 and do MGCP?

Patrick.

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