Subject: Re: Need to standardize the defs for "AS" and "ASP".

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Thu, 23 Aug 2001 18:02:16 -0500

......resend

John,

IUA and M2UA have no "Routing Keys".

In M2UA is is possible to have more than one Link associated with a
single AS.

In SUA and M3UA AS is identified by RC.
In M2UA AS is idenitified by a list or sublist of IIDs.

Please see other comments below...

--brian

John Schantz wrote:                           (Thu, 23 Aug 2001 07:52:49)
> 
>    Actually this is a great topic because AS and ASP are the most
>    confusing concepts in all of these documents.  I know I wrestled with
>    for a while and so have many others, and people are still struggling
>    with them.
>    
>    
>    
>    The name is very misleading, Application Server.  It is not an
>    application and it is not a server.  The real applications/servers sit
>    on top of the protocol stack, away from any UA.  Many of the documents
>    imply that it is a real signalling node or at least part of one, this
>    is perception is wrong too.
>    
>    
>    
>    Actually, I think the definition that you quote from SUA might be the
>    closest one:  "...a logical entity serving a specific routing key".
>    You can also dig this meaning out of M3UA.
>    
>    
>    
>    Maybe we can generate a good definition from the facts about AS:
>    
>    
>    
>    1)  Has a 1-1 correspondence with an RK (i.e., it is bounded by a
>    single RK and the traffic defined by the RK),

The RK only defines the traffic in the SG --> AS direction.  Basing
the definition of AS on RK is not sufficient.  The definition of RK
relies on AS.  (In M3UA: RK when applied to a message in the
SG --> AS direction must result in a single AS).  The 1:1 correspondence
is the result of this restriction placed on RK, and is not part of the
definition of an AS.

IUA and M2UA have no Routing Key.

>    
>    2)  It only exists within the specific UA in question,

This is a implementation depedent restriction which does not currently
exist.  There is nothing stopping me as things stand from, say, assigning
the same RC-value in both M3UA and SUA to indicate a single AS which
has "appearances" both in M3UA and SUA.  Also, nothing is acheived by
this restriction.

>    
>    3)  Its traffic is handled by a collection of SCTP end-points, these
>    have been defined as ASPs.  AS has also been defined as the collection
>    ASPs serving this specific set of traffic.

What do you mean by "serving"?  An ASP which is in STANDBY or INACTIVE
with respect to an AS is not "handling traffic" but is still involved
with both the AS and the SGP with respect to an AS.

I think that the relationship between AS and ASP regarding traffic is
clearly defined by the AS and ASP states and procedures.  These procedures
have been made common in the remaining drafts and there are no
contradictions between UAs.

>    I can only conclude that an AS is only a routing concept (logical
>    entity) association with a specific set of signalling traffic (RK)
>    that only exists within the specific UA in question and has an
>    assigned collection of SCTP end-points handling it traffic.

This may be because your definition of AS is based on routing.  The current
definitions place requirements on routing based on the definition of AS.

On the contrary, your description is close to fitting SUA's definition of
Routing Context:

   "Routing Context - An Application Server Process may be configured to 
   process traffic within more than one Application Server.  In this 
   case, the Routing Context parameter is exchanged between the SGP and 
   the ASP (or between two ASPs), identifying the relevant Application 
   Server.  From the perspective of an SGP/ASP, the Routing Context 
   uniquely identifies the range of traffic associated with a 
   particular Application Server, which the ASP is configured to 
   receive. There is a 1:1 relationship between a Routing Context value 
   and a Routing Key within an AS.  Therefore the Routing Context can 
   be viewed as an index into an AS Table containing the AS Routing 
   Keys. The Routing Context also uniquely identifies an SS7 entity 
   (point code) into a SS7 network, as presented by the SG."

When it was proposed that this definition be used for M3UA it was
strongly opposed by some people.  Were you not one of them?

Based on your current comments, I would like to repropose that the
SUA definition of Routing Context also be used in M3UA.

--brian

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

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From: "Brian F. G. Bidulock" <[email-masked]>
Date: Thu, 23 Aug 2001 14:31:34 -0500

John,

--brian

--brian

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

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