Hi,
I am also having this problem. I found a book called
"ASN.1 Communication between Heterogeneous Systems"
written by Olivier Dubuisson, who looks to be an
expert on ASN.1, where it is explicitly said:
- If the ENUMERATED type is extensible (or if the
module includes the EXTENSIBILITY IMPLIED clause in
its header), a preamble of one bit is appended to the
bit-field (without being octet-aligned).
"Normally small non-negative whole number encoding"
- if 0 <= n <= 63, a 0-bit is appended to the
bit-field (without being octet-aligned), followed by
the binary encoding of n on 6 bits.
Regards
--- "Nichols, Roger" <Roger.Nichols@xxxxxxxxxxxx>
wrote:
>
> Hi,
>
> Is this the proper forum to ask a question about
> 'why' something is
> coded the way it is?
>
> We are developing a V.34 enabled T.38 end point, and
> are confused by the
> Wireshark decoding. It seems the Wireshark decoder
> is aligning fields
> which are extension values. For example, the 2002
> T.38 ASN.1 notation
> for V.34 Data Field values. We are not aligning
> these enumeration
> values, but Wireshark does. See line 1211 of
> packet-per.c, a comment
> which says to align without giving a reference, and
> 1214 which does the
> alignment. Reading ITU X.691 section 13, I would
> not expect this
> beahvior. As Wireshark community is the only place
> I know of an
> existing product which handles the V.34 additions to
> T.38, it seems a
> good place to ask. Why are these values aligned?
> We could not find an
> ITU reference giving us reason to do so.
>
> Thanks,
>
> Roger Nichols
> Firmware Engineer
>
> Cantata Technology, Inc. (a Dialogic company)
> 15 Crawford Street
> Needham, MA 02494
> USA
>
> Tel: 781 292 9399
> Fax: 781 453 3521
> Email: roger.nichols@xxxxxxxxxxxx
> Web: www.dialogic.com
>
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