Subject: RE: SDP and ';' comments

From: "Tulpule, Naren" <[email-masked]>
Date: Fri, 18 May 2001 10:37:25 -0700

The resolution to Troy's initial statement is not only because of the way an
SDP ends, but also in the way that the octetString terminal will force the
Megaco parser to pull everything up to the '}' into the octetString.  
[Naren] Depends on the parser implementation... when there's no doubt that
the so-called octetstring is nothing but SDP, so you may not need to call
the Megaco octetstring parser followed by the SDP parser - you can call the
SDP parser in place. In this case the SDP parser can terminate when it
cannot understand the beginning of a line.

Pasting from Naren's post from last September (for which I never saw any
responses): 

    4. escaping "}" in SDP strings 
            I don't know if  "}" can appear in SDP attribute or VcId or
other 
    values. Nonetheless to be safe, especially on the MGC side when you
might 
    just want to treat SDP description as opaque, why not delimit the the 
    description with a line that starts with "==" (two "=" symbols) or a
similar 
    illegal combination? Using "\}" is really not feasible. 

The issue isn't that "}" could appear in SDP - it's whether "\}" could
appear in SDP.  If it can not, then it is okay for the Megaco parser to
translate the "\}" to "}", and pass the resulting string to the SDP parser.

[Naren] So far I haven't seen either "}" or "\}" in SDP. The thing is, we
don't really need to impose any restrictions on SDP at all. Just start a new
line with something which cannot occur after EOL in SDP  and define that to
be the "end-of-SDP-start-of-Megaco" delimiter (e.g. "==") instead of RBRKT.
(For the aesthetes, RBRKT can still follow this delimiter).

These views are mine alone, not those of Intel or Trillium. 
-- Naren 
Narendra C. Tulpule         310-442-9222 
SMTS, Trillium (an Intel company) 
12100 Wislshire Bl #1800 Los Angeles CA 90025

---

From: Troy Cauble <[email-masked]>
Date: Fri, 18 May 2001 15:36:37 -0400

"Tulpule, Naren" wrote:

[Naren]
So far I haven't seen either "}" or "\}" in SDP. The thing is, we don't
really need to impose any restrictions on SDP at all. Just start a new
line with something which cannot occur after EOL in SDP  and define
that to be the "end-of-SDP-start-of-Megaco" delimiter (e.g. "==") instead
of RBRKT. (For the aesthetes, RBRKT can still follow this delimiter).

Very clean.  I like this idea a lot.  It saves quoting
the '}' characters.

The delimiter could even be whitespace.  Or any line that doesn't

match "[a-z]=".

But it's probably too late to get agreement on such a change.

-troy