Subject: RE: Multiple ASPs per host.

From: "Sidebottom, Greg [BCNR:7M01:EXCH]" <[email-masked]>
Date: Tue, 3 Apr 2001 10:49:35 -0400

Forwarding to the list for Howard - I hope!

I have also included a reply - see below....

BTW - I see some "grumbling" between the lines re problems with the Sigtran
list - I've had minor problems myself.   If you are experiencing problems
can you drop me a quick e-mail (to [email-masked] ).  I will
try consolidate any problems to the support people.  There has been a server
change to address some recent problems.  I'll try to update everyone as soon
as possible.

Greg

 -----Original Message-----
From: 	May, Howard [mailto:[email-masked]] 
Sent:	Thursday, March 22, 2001 9:22 AM
To:	[email-masked]
Cc:	Sidebottom, Greg [BCNR:7M01:EXCH]
Subject:	Multiple ASPs per host.

Greg, please can you submit this to the sigtran mailing list for me as it is
refusing to let me submit messages!  I am continuing to try to resolve this
problem.  Thank you very much.

Hi there,

Multiple ASPs per host
**********************

My particular interest is currently with M3UA but I guess this question
applies to other User Adaptation Layers.

Consider a simple system:  
One host with one SG with a single SGP.  Another host with two ASPs within
two ASs (a single AS per ASP).  The Routing Keys are statically configured
in the SG.

My understanding is that there will be a separate SCTP association between
each ASP and the SG hence there will be two SCTP associations between the
same two hosts.

[Greg] Yes.  There will be two SCTP associations: SG-ASP1 and SG-ASP2.  One
host contains two SCTP end-points for the two ASPs.

Question: 
When an SCTP association is established, how does an SG identify which ASP
is at the other end?

In the simple system described above we cannot discriminate between the
associations based on IP addresses as they both have the same IP address.
We cannot discriminate based on client port number because the standards do
not control these.  We cannot wait to see what Routing Key configuration is
used because we are using static configuration.

please help!

Howard May

[Greg] The two ASPs contain unique SCTP end-points and therefore have unique
transport addresses.  If they use the same IP address then they must use
different port numbers.   I not sure what you mean by "We cannot
discriminate based on client port number because the standards do not
control these".

Cheers,

   Greg

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From: "Sidebottom, Greg [BCNR:7M01:EXCH]" <[email-masked]>
Date: Wed, 4 Apr 2001 12:46:23 -0400

Hi Howard, 

Response below ...

 -----Original Message-----
From: 	May, Howard [mailto:[email-masked]] 
Sent:	Tuesday, April 03, 2001 11:43 AM
To:	[email-masked]
Cc:	Sidebottom, Greg [BCNR:7M01:EXCH]
Subject:	RE: Multiple ASPs per host.

Hi Greg,

In my previous mail I made the some what unclear statement that:

"We cannot discriminate based on client port number because the standards do
not control these"

What I meant was that when an ASP SCTP association is established M3UA
cannot specify the local port number that is used.  Before you all start
shouting I have looked a little closer at SCTP and found that there IS an
optional parameter to specify the port number to be used.

Just to clarify, can you confirm that:-

In the simple system I described below, the SG needs to be pre-configured to
know the transport addresses used by both ASPs.  If the ASPs use the same IP
address(es) then the SG has to identify the ASP a newly established
association belongs to based on the port number.

Cheers

Howard May

[Greg] I can confirm that - but I'll clarify that the SG may not have to be
pre-configured to make this work.  I guess whether this is pre-configured or
"dynamically" configured depends on the capability of the SG.  The M3UA
protocol provides a registration mechanism that can be used to set up the
AS/ASP configuration - this can be related to the two unique incoming SCTP
associations and voila!

P.S. still having trouble with the mailing list.

[Greg] Hopefully this is better today. Some changes were made yesterday -
we'll see today if they worked!

Cheers,

   Greg

-----Original Message-----
From: Sidebottom, Greg [BCNR:7M01:EXCH]
[mailto:[email-masked]]
Sent: 03 April 2001 15:50
To: [email-masked]
Subject: RE: Multiple ASPs per host.

Greg

 -----Original Message-----
From: 	May, Howard [mailto:[email-masked]] 
Sent:	Thursday, March 22, 2001 9:22 AM
To:	[email-masked]
Cc:	Sidebottom, Greg [BCNR:7M01:EXCH]
Subject:	Multiple ASPs per host.

Hi there,

Multiple ASPs per host
**********************

Question: 

please help!

Howard May

Cheers,

   Greg

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