Subject: RE: [Sigtran] Recommendation for SUA modifications

From: [email-masked]
Date: Thu, 13 Oct 2005 13:04:37 +0300

>It might be best then to leave the APC mandatory in the SCON, 
>particularly when one considers that not even a TC-user is 
>spared the use of a point code in these management primitives 
>(Q.771/2.2.3).
>
>I think we need, for the time being, to note in the I-G that 
>Point Codes are mandatory in all Addresses to or from an SG, 
>to preclude the interoperability difficulties of an SG or ASP 
>underspecifying an address.
>If the additional work you mention ever materializes in the 
>future, placing point code in addresses could later be relaxed.

I agree.  Since a TC-user may pass this down, then I think it
mostly likely is required for SUA.

John

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From: "Haresign Lincoln" <[email-masked]>
Date: Thu, 13 Oct 2005 09:25:44 -0400

Brain,

[brian] Nevertheless, Lincoln seems to be avoiding this question,
perhaps you can venture an answer: "How does the SG know what address to
place in the OPC of the message if it receives an SUA message (SCON or
otherwise) from the ASP that does not include a corresponding point code
in the message?"

Easy answer (didn't know I was avoiding it).  If you are referring to
the PC in the MTP label, it depends on the routing keys of the ASP.  I
can elaborate on this further if you'd like.

Regards,
Lincoln

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Brian F. G. Bidulock
Sent: Wednesday, October 12, 2005 7:08 PM
To: Tolga Asveren
Cc: [email-masked]
Subject: Re: [Sigtran] Recommendation for SUA modifications

Tolga,

Tolga Asveren wrote:                             (Wed, 12 Oct 2005
14:34:27)
> > That would be sending messages with RC 1 in them before receiving 
> > ASP Active Ack for RC 1.  That passage does not speak to the 
> > addressing of the messages.
> > Other passages do.  The SG provides uniform connectivity to all ASPs

> > in an AS and can route any messagew within a Network Appearance.
> [TOLGA]Here I still think different, i.e. I consider AS state to be 
> honored in both directions of message flow based on the above
passage-.

That is true enough for MTP/M3UA, but for SCCP/SUA the responding
address (in a connection response) is not necessarily the address to
which the connection request was sent.  SUA has the ability for relay
internal to the ASP or over the IP network, that we precluded in the
M3UA RFC.

Following your stricter interprentation would require, for connection
oriented operation, when the responding address differs from the address
of the request, of responsding to a connection request using an RC
differennt from that upon which the connection request arrived.

Nevertheless, Lincoln seems to be avoiding this question, perhaps you
can venture an answer: "How does the SG know what address to place in
the OPC of the message if it receives an SUA message (SCON or otherwise)
from the ASP that does not include a corresponding point code in the
message?"

Remember that Lincoln says that his ASPs register only using GT (or
maybe SSN) with no point code, therefore there is no point code in the
routing key associated with the routing context and that, if I interpret
him correctly, that it is too difficult a provisioning task for his ASP
to provide one at registration.

For arguments sake, assume that the SG supports mutliple point codes
(otherwise the task is trivial).

--brian

--
Brian F. G. Bidulock
[email-masked]
http://www.openss7.org/

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From: "Haresign Lincoln" <[email-masked]>
Date: Thu, 13 Oct 2005 09:40:13 -0400

Brian,

When an ASP sends a message to the SG (e.g., a CLDT) without a point
code in the source address, how does the SG know what to put in the OPC
of the MTP label?

If the SG can do this, it can also determine what the affected PC is of
the SCON coming from the same ASP.  

Regards,
Lincoln 

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Brian F. G. Bidulock
Sent: Thursday, October 13, 2005 5:14 AM
To: Tolga Asveren
Cc: [email-masked]
Subject: Re: [Sigtran] Recommendation for SUA modifications

Tolga,

> > > "The ASP SHOULD NOT send Data or SSNM messages for the related 
> > > Routing Context(s) before receiving an ASP Active Ack message, or 
> > > it will risk message loss."
> > > I know it is not a "MUST NOT" but still it is nota good thing to 
> > > do unless one is aware of consequences and happy with them.
> >
> > addressing of the messages.  Other passages do.  The SG provides 
> > uniform connectivity to all ASPs in an AS and can route any messagew

> > within a Network Appearance.
passage-.

I know what I meant by that sentence when I wrote it.

One of the possible responses of the SG to an ASP Active request is an
ASP Inactive Ack, or management blocking.  My point was that if an ASP
blindly sends messages to the SG following ASP Active, without waiting
for an ASP Active Ack, that the SG may have to discard them in the case
that it responds with an ASP Inactive Ack or management blocking.

Therefore, if the ASP wishes to avoid risking "message loss", it will
wait for the ASP Active Ack.

If you recall, I was not successful on the argument of symmetrical flows
within a routing context.  RK is only used by an SG for routing messages
to the ASP, not visa versa.

If messages in M3UA could not be sent from ASP to SG with different
addresses than appear in the RK, then the SG would have to compare the
routing labels in DATA messages received from the ASP to police the
arrangement and do something (no procedure exists yet) in event of a
violation.  Currently, the SG can just process the message for M3UA,
because the addresses in it are fully specified and the message is self
contained.  The SG even knows the proper RC value to place in any SSNM
messages sent to the ASP in response to respond to the proper AS,
regardless of the addresses in the message.

In fact there is no procedure in either M3UA or SUA that relies on the
ASP applying a symmetric routing key to that of the SG.

In SUA placing a symmetric requirement on the ASP is not possible,
because not even addresses are symmetric (a transaction query often
includes GT, whereas the response does not).

All that the RC does is identify the AS to an SG and corresponds to a
routing key used by the SG to send messages to the ASP.  It is a false
assertion that missing parts of messages sent from ASP to SG can be
recreated based on RC.

--brian

--
Brian F. G. Bidulock
[email-masked]
http://www.openss7.org/

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From: "Haresign Lincoln" <[email-masked]>
Date: Thu, 13 Oct 2005 13:53:47 -0400

Brian,

I have no idea what you are talking about.  I never said ASPs route on
source address.

Lincoln 

-----Original Message-----
From: Brian F. G. Bidulock [mailto:[email-masked]] 
Sent: Thursday, October 13, 2005 1:51 PM
To: Haresign Lincoln
Cc: [email-masked]; [email-masked]; [email-masked]
Subject: Re: [Sigtran] Recommendation for SUA modifications

Haresign,

Haresign Lincoln wrote:
(Thu, 13 Oct 2005 09:46:23)
> John,
> 
> The TC-USER "may" pass down the point code.  Fine.  In that case, the 
> ASP has knowledge of it's point code.  However, it is not a MUST.
> Therefore, let's try to solve that case.  Why do you feel it is 
> necessary to provion a Point Code on the ASP when the ASP never uses 
> the knowledge in normal routing scenarios?

ASPs don't route on source addresses.  Neither do SGs.  Neither does
SS7.
Gee, neither does IP.

--brian

--
Brian F. G. Bidulock
[email-masked]
http://www.openss7.org/

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From: "Haresign Lincoln" <[email-masked]>
Date: Thu, 13 Oct 2005 13:57:00 -0400

Brain,

The RC is optional.  Read the spec.

Lincoln 

-----Original Message-----
From: Brian F. G. Bidulock [mailto:[email-masked]] 
Sent: Thursday, October 13, 2005 1:55 PM
To: Haresign Lincoln
Cc: Tolga Asveren; [email-masked]
Subject: Re: [Sigtran] Recommendation for SUA modifications

Haresign,

Haresign Lincoln wrote:
(Thu, 13 Oct 2005 13:16:45)
> Brian,
> 
> Actually, the fact that an ASP can represent more than one point code 
> is even a stronger argument for having RC as an optional parameter in 
> the SCON message when being sent from ASP to SG and affected PC as 
> conditional.  And the SG does NOT always have to do anything with the 
> SCON.  After all, you said yourself that this was an optional
procedure.

Now you want to make RC optional?

> 
> However, if we enable the ability for the ASP to send the SCON with 
> RC, it opens the door to developers implementing features such as 
> reducing traffic to congested ASPs within an AS.  I don't think it is 
> necessary to define how this would be done.  I just want to have the 
> abilty to do it.

If you need it so bad, provision a point code.

--brian

--
Brian F. G. Bidulock
[email-masked]
http://www.openss7.org/

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From: "Haresign Lincoln" <[email-masked]>
Date: Fri, 14 Oct 2005 08:20:38 -0400

Brian,

I have no idea what you mean by this statement.  But a global title can
appear in both the called and calling address of a CLDT and also a UDT.

Regards,
Lincoln 

-----Original Message-----
From: Brian F. G. Bidulock [mailto:[email-masked]] 
Sent: Thursday, October 13, 2005 7:46 PM
To: Haresign Lincoln
Cc: Tolga Asveren; [email-masked]
Subject: Re: [Sigtran] Recommendation for SUA modifications

Lincoln,

GTT is only performed in one direction.

--brian

--
Brian F. G. Bidulock
[email-masked]
http://www.openss7.org/