Hi Krishna, The problem you are seeing has nothing to do with incompatible versions of the ASN.1 standards. For your purposes, everything after the 1994 version is compatible in these protocols.
What I believe you are seeing is a change in the T.38 standard in the late 90's that broke backward compatibility. It had to do with adding extensibility markers to ENUMERATED types. This changed the PER encoding of the base types. This is the reason for needing to add "--old_asn" in the T.38 modem program to talk to Cisco devices. Regards, Ed Day Objective Systems, Inc. REAL WORLD ASN.1 AND XML SOLUTIONS Tel: +1 (484) 875-9841 Fax: +1 (484) 875-9830 Toll-free: (877) 307-6855 (USA only) mailto:[EMAIL PROTECTED] http://www.obj-sys.com ----- Original Message ----- From: "Bujji Krishna R B" <[EMAIL PROTECTED]> To: "Dean Anderson" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Monday, October 06, 2003 12:58 AM Subject: [ASN.1] RE: [T38] Re: [OpenH323]ASN.1 Version in T.38 > > Hi Dean, > I understand that both X.680 and X.691 are to be used . But my > question was that > Which version of ASN.1 to be used, as the version information specified > is different in > both H.225 standard and T.38 Standard. > > Thanks > Krishna > > > > -----Original Message----- > From: Dean Anderson [mailto:[EMAIL PROTECTED] > Sent: Sunday, October 05, 2003 4:05 AM > To: [EMAIL PROTECTED] > Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]; > [EMAIL PROTECTED]; [EMAIL PROTECTED] > Subject: [T38] Re: [OpenH323]ASN.1 Version in T.38 > > > You must follow both. X.680 specifies the notation. X.691 specifies > PER, which is a type of encoding. Think of it as the high level > language, and the object code. > > --Dean > > On Sat, 4 Oct 2003, Bujji Krishna R B wrote: > > > > > Hello, > > I have a query regarding the ASN.1 Version specified in H.323 > > Version 3 standard and T.38 standard. > > > > H.225 version 3 and H.245 version 5 specifies the following ASN.1 > > Versions: > > > > ITU-T Recommendation X.680 (1994): Information Technology - Abstract > > Syntax Notation One (ASN.1) - Specification of basic notation. ITU-T > > Recommendation X.691 (1996): Information Technology - ASN.1 Encoding > > Rules - Specification of Packed Encoding Rules (PER). > > > > ITU-T T.38 Recommendation specifies the following version of ASN.1 > > ------------------------------------------------------------------- > > ITU-T Recommendation X.680 (1997), Information technology - Abstract > > Syntax Notation One (ASN.1): Specification of basic notation. > > > > ITU-T Recommendation X.691 (1997), Information technology - ASN.1 > > encoding rules - Specification of Packet Encoding Rules (PER). > > ---------------------------------------------------------------------- > > -- > > ----------- > > > > I would like to know which version of ASN.1 to be followed. Could some > > > one explain the differences in these versions. Would there be any > > problems if ASN.1 X.680 (1994) and X.691 (1996) is used in T.38 > > Encoding/Decoding. > > > > Also, T38Modem README specifies the following > > "Cisco Users: You additionally need to use --old-asn and > > --h245tunneldisable options." Are these options used to overcome the > > ASN.1 Version Differences. > > > > > > Thanks > > Krishna > > > > **************************Disclaimer********************************** > > ** > > > > Information contained in this E-MAIL being proprietary to Wipro > > Limited is 'privileged' and 'confidential' and intended for use only > > by the individual or entity to which it is addressed. You are > > notified that any use, copying or dissemination of the information > > contained in the E-MAIL in any manner whatsoever is strictly > > prohibited. > > > > ********************************************************************** > > ***** > > > ------------------------------------------------------------------------ > > Check the FAQ before asking! - > http://www.openh323.org/~openh323/fom.cgi > > The OpenH323 Project mailing list, using Mailman. To unsubscribe or > > change your subscription options, goto > > http://www.openh323.org/mailman/listinfo/openh323 > > Maintained by Quicknet Technologies, Inc - http://www.quicknet.net > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > T38 mailing list > [EMAIL PROTECTED] > http://www.openh323.org/mailman/listinfo/t38 > > **************************Disclaimer************************************ > > Information contained in this E-MAIL being proprietary to Wipro Limited is > 'privileged' and 'confidential' and intended for use only by the individual > or entity to which it is addressed. You are notified that any use, copying > or dissemination of the information contained in the E-MAIL in any manner > whatsoever is strictly prohibited. > > ***************************************************************************
