Subject: [Sigtran] M3UA-v02 Last Call Comment

From: "Samuel Dur D. Jeyaseelan" <[email-masked]>
Date: Mon, 26 Apr 2004 08:30:39 -0500 (CDT)

Hi all,

An SCCP message(cdpa->ri=rt_on_gta,cgpa->ri=rt_on_pcSsn) from
networkAppearance 1 is sent to SG. Since message is destined to SG, it
performs a GTT which results in PC/SSN of networkAppearance 2, here
my question is What will happen to cgpa parameters ? because SG
can not give cgpa->pc/ssn of networkAppearance 1 to networkAppearance 2.

I searched in RFC but could not find any answer other than section 1.5.3
in old_rfc which is not sufficient , i feel.

--Samuel

  Alcatel USA, Inc.                  Internet: <userid>@ssd.usa.alcatel.com
  1000 Coit Road, Plano, Texas 75075
  ******* The opinions expressed are not those of Alcatel USA, Inc. *******

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From: "Tolga Asveren" <[email-masked]>
Date: Mon, 26 Apr 2004 09:53:11 -0400

Hi Samuel,

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]On Behalf Of
> Samuel Dur D. Jeyaseelan
> Sent: Monday, April 26, 2004 9:31 AM
> To: [email-masked]
> Subject: [Sigtran] M3UA-v02 Last Call Comment
>
>
>
> Hi all,
>
[TOLGA]I think GTT result always should end up in the same network, i.e. the
same NA. IMO, to do otherwise, you would need a IWF on top of SCCP
(interworking two SCCP instances). I furthermore believe, this way of
operation is SS7 specific, not only applicable for M3UA case, so I would
think not to mention about it should be fine.

---

From: "Samuel Dur D. Jeyaseelan" <[email-masked]>
Date: Mon, 26 Apr 2004 09:16:46 -0500 (CDT)

Hi Tolga,

> think not to mention about it should be fine.

Fine, but When will SG route the message across networkAppearances?

---

From: "Tolga Asveren" <[email-masked]>
Date: Mon, 26 Apr 2004 10:23:04 -0400

Hi Samuel,

> From: Samuel Dur D. Jeyaseelan [mailto:[email-masked]]
> Sent: Monday, April 26, 2004 10:17 AM
> To: Tolga Asveren
> Cc: [email-masked]
> Subject: RE: [Sigtran] M3UA-v02 Last Call Comment
>
>
>
> Hi Tolga,
>
> > > From: [email-masked]
> [mailto:[email-masked]]On Behalf Of
> > > Samuel Dur D. Jeyaseelan
[TOLGA]I believe this should be done on application level. For example :
                                 SG
     +-------+              +---------------+
     |  SEP  +--------------| SS7 Ntwk |M3UA|              ----
     +-------+   SS7 links  |   "A"    |    |            /      \
                            |__________|    +-----------+  ASPs  |
                            |          |    |            \      /
     +-------+              | SS7 Ntwk |    |              ----
     |  SEP  +--------------+   "B"    |    |
     +-------+              +---------------+

Figure2 from RFC3332

SG receives messages from NtwkA, routes it to ASP. Then it is up to the
application on ASP to process this message and possibly to initiate a
message to NtwkB.

---

From: "Samuel Dur D. Jeyaseelan" <[email-masked]>
Date: Mon, 26 Apr 2004 10:18:02 -0500 (CDT)

Hi Tolga,

> [TOLGA]I believe this should be done on application level. For example :

I think at SG GTT is mandatory to move messages from one networkAppearance
to another networkAppearance. This is one of the reasons why an instance
of SCCP layer is kept over M3UA. One more think is only after the GTT, SG 
routes the message to ASP with the help of new PC/SSN(this is true only
for this thread).

From 'Figure2 RFC3332' , SG even can route the messages to another
networkAppearance without he help of ASP. This is done just by doing GTT.

Since RFC3332 mentions about GTT , it should also mention about few
important questions such as my first_emial_question, i feel .

---

From: "Tolga Asveren" <[email-masked]>
Date: Mon, 26 Apr 2004 11:23:03 -0400

Hi Samuel,

> Sent: Monday, April 26, 2004 11:18 AM
> To: Tolga Asveren
> Cc: [email-masked]
[TOLGA]I don't see how one can move messages between NA, without IWF. If you
have one SCCP instance, this means that it is SCCP for a specific PC, which
resides in one network. To relay between two networks, you need something on
top of SCCP -something which interworks two SCCP instances on different
PCs/networks-.
> networkAppearance without he help of ASP. This is done just by doing GTT.
[TOLGA]IMO, this is not the intention.
> important questions such as my first_emial_question, i feel .
[TOLGA]IMO, your questions are relate with SS7, not specifically with M3UA.
Also in SS7, to achieve what you want to do, you need something on top of
SCCP.

---

From: "Samuel Dur D. Jeyaseelan" <[email-masked]>
Date: Mon, 26 Apr 2004 11:22:32 -0500 (CDT)

Hi Tolga,

> top of SCCP -something which interworks two SCCP instances on different

I dont say IWF is not required, what i am saying is without SCCP layer
SG will simply become a relay node and it can not route messages 
across networkAppearances. GTT function at SCCP layer adds an
intellligence to SG to route the SCCP messages across networkAppearances.
Just imagine an SG without SCCP layer that means it has only MTP3 layer.
This MTP3 layer shall never know the point codes of another
networkAppearance, it knows only about its local point codes means point
codes within the origination networkAppearance. Finally IWF comes into
picture while delivering messages from one protocol to another protocol.

> [TOLGA]IMO, this is not the intention.
Yes, but this is one of the intentions.

> Also in SS7, to achieve what you want to do, you need something on top of
To do this(to differentiate point codes between NAs) nothing is required
on top of SCCP. Just SCCP is enough.

If my question is not related with M3UA, then rfc3332 should not talk
about GTT and SCCP layer and once again i am saying it will become simply
a relay node.

---

From: "Tolga Asveren" <[email-masked]>
Date: Mon, 26 Apr 2004 13:05:30 -0400

Hi Samuel,

[..snip..]
> picture while delivering messages from one protocol to another protocol.
[TOLGA]I don't know, whether a GTT resulting in a PC in another network is
reasonable or not. BTW, if you consider the issue from M3UA point of view,
it doesn't matter whether it is SCCP or an IWF application, which runs on
top of it. Transferring of messages from one network to the other one is not
done in M3UA/MTP3 itself. If you want to use GTT (probabaly with multiple
SCCPs), then where does M3UA come into play, while transferring the message
from one network to the other one? Somebody else decides for the network, to
which the message is going to be sent, M3UA just delivers it.
> on top of SCCP. Just SCCP is enough.
[TOLGA]When you cross protocol boundaries, probably you will need some kind
of IWF and two instances of SCCP, one in each network. And as I mentioned
above, even this is besides the point, the issue is that it is not M3UA that
does the transfer between networks. The transfer logic is somewhere on the
upper layers, either on a local IWF or on an application in ASP.
> about GTT and SCCP layer and once again i am saying it will become simply
[TOLGA]It talks about it to show a possible configuration. But please note
that configuration does not change the way M3UA works. What do you mean
exactly with "it will become simply a realy node" ?