this is a good question.
Since no one has answered I'll try...
I think they are a bit like regular expressions.
[] usually means an optional component
<> can be a tag which can be substituted for some value.
In HTML or XML, it marks the start or end of some element.
* usually means zero or more - in ABNF, the * comes before the element
which can be used zero or more times. In regular expressions,
the * comes after.
Documents should either refer to another document or well-known
specification or describe the notation within.
For example, RFC4566 does the later:
An SDP session description consists of a number of lines of text of
the form:
<type>=<value>
where <type> MUST be exactly one case-significant character and
<value> is structured text whose format depends on <type>. In
general, <value> is either a number of fields delimited by a single
space character or a free format string, and is case-significant
unless a specific field defines otherwise. Whitespace MUST NOT be
used on either side of the "=" sign.
An SDP session description consists of a session-level section
followed by zero or more media-level sections. The session-level
part starts with a "v=" line and continues to the first media-level
section. Each media-level section starts with an "m=" line and
continues to the next media-level section or end of the whole session
description. In general, session-level values are the default for
all media unless overridden by an equivalent media-level value.
Some lines in each description are REQUIRED and some are OPTIONAL,
but all MUST appear in exactly the order given here (the fixed order
greatly enhances error detection and allows for a simple parser).
OPTIONAL items are marked with a "*".
What stuff are you trying to understand?
Are you looking at an RFC?
Regards,
Attila
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
Sabyasachi Samal
Sent: 04 March 2008 04:41
To: [email protected]
Subject: [Sip-implementors] Notations used in IETF docs
Hello,
Though my question is not relevant to this group still i am posting this
to get some idea as many members may aware of this.
Question:
Like rfc 2119 to know the syntaxt and keywords used in rfc, is there any
document which mentioned about the syntax of IETF docs meant for binary.
e.g.
[aaa]
<bbb>
[<ccc>]
* <ddd> etc
If anyone can help me in this it will be great.
--
Regards,
Sabyasachi Samal
IMS Testing Solution
Nethawk Networks India Pvt. Ltd.
Bhubaneswar
Orissa, India
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