Subject: RE: [Megaco] ABNF TerminationId definition

From: Raphael Tryster <[email-masked]>
Date: Sun, 21 Dec 2003 11:57:18 +0200

Trying again and adding some more questions; maybe someone will answer this
time.

TerminationID        = "ROOT" / pathNAME / "$" / "*" 
 
pathNAME        = ["*"] NAME *("/" / "*"/ ALPHA / DIGIT /"_" / "$" ) ["@"
pathDomainName ] 

NAME = ALPHA *63(ALPHA / DIGIT / "_" ) 

1.	All the examples I have seen suggest that the unit of wildcarding is
delimited by slashes. "For example, if there were TerminationIDs of R13/3/1,
R13/3/2 and R13/3/3, the TerminationID R13/3/* would match all of them".
But the ABNF seems to allow "*" to appear just about anywhere.  From a
performance point of view, it is much more efficient to index termination
identifiers by easily recognizable logical units, e.g. term1/term2/term3,
than to allow wildcarding in arbitrary places, requiring searching for
matches.  Do actual implementations allow unrestricted freedom, or can one
make simplifying assumptions?

2.	Is it legitimate to use underscore "_" instead of slash "/" as a
logical delimiter?  Does anyone actually do this?  Is anything else a
legitimate delimiter?

3.	Would the above definition of pathNAME be any different if ALPHA was
substituted for NAME?  The existing definition seems to be ambiguous, as for
example, an identifier consisting entirely of alphabetic characters could be
parsed such that all characters are assigned to NAME, or the first assigned
to NAME and the rest in the repeating optional ALPHA, or anything in
between.

4.	"Terminations are referenced by a TerminationID, which is an
arbitrary schema chosen by the MG".  Does this mean that only an MGC has to
worry about what form the MGs it works with might choose for their
termination identifier, while an MG can impose whatever restrictions it
wants without concern that it will impede interoperability?  

Raphael Tryster

	-----Original Message-----
	From:	Raphael Tryster [SMTP:[email-masked]]
	Sent:	Tuesday, 13 August 2002 16:02
	To:	[email-masked]'
	Subject:	RE: [Megaco] ABNF TerminationId definition

	Here is something I found in the archive that nobody answered.  In
addition to Steven's questions, for which I would also be interested in the
answers, I am curious about the following:

	What is the purpose of the leading "*" in pathNAME?  Following it
with NAME seems to restrict wildcarding in strange ways.  For example:

	[email-masked] <mailto:[email-masked]>  is allowed. 
	abc/[email-masked] <mailto:abc/[email-masked]>  is allowed. 
	abc/[email-masked] <mailto:abc/[email-masked]>  is allowed. 
	*/[email-masked] <mailto:*/[email-masked]>  is not allowed. 

	Can anyone explain the reasoning? 

	Raphael Tryster 

	-----Original Message----- 
	From:   Steven Weisz [SMTP:[email-masked]] 
	Sent:   Monday, 15 October, 2001 10:53 PM 
	To:     [email-masked]' 
	Subject:        [Megaco] ABNF TerminationId definition 

	Hi List, 

	        I've taken a close look at the H.248 document and the latest
IG and 
	I noticed that the ABNF does not allow TerminationIds in the form 

	[email-masked] 

	OR 

	[email-masked] 

	If you look closely at the ABNF we have: 

	; Total length of pathNAME must not exceed 64 chars. 
	pathNAME             = ["*"] NAME *("/" / "*"/ ALPHA / DIGIT /"_" /
"$" ) 
	                       ["@" pathDomainName ] 

	; ABNF allows two or more consecutive "." although it is meaningless

	; in a path domain name. 
	pathDomainName       = (ALPHA / DIGIT / "*" ) 
	                       *63(ALPHA / DIGIT / "-" / "*" / ".") 
	                       
	TerminationID        = "ROOT" / pathNAME / "$" / "*" 

	What I'm wondering, are [email-masked] and [email-masked] valid TerminationIds
and the 
	ABNF doesn't cover them or are they not allowed. 

	Thanks, 

	Steven 

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