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Re: Protocol operations proposal deadline




>>>>> Randy Presuhn writes:

>> Although we should learn from history and have a few unused bits in
>> the new PDU format. The traditional Internet protocol formats
>> always lead to some unused bits due to the alignment of various
>> fields. ASN.1 itself does not lead to some unused bits in this
>> natural way and so they have to be designed into the protocol.

Randy> This is a limitation of the way the IETF has used ASN.1, rather
Randy> than ASN.1 itself.  By using "extensibility markers" or the
Randy> "DEFINED BY" constructs in the ASN.1 grammar, extensibility is
Randy> readily supported.  Examples include X.500 and that other
Randy> management protocol.

Sure, you can do these things properly with ASN.1.

My point however was that other more traditional word aligned packet
formats usually lead automatically to some spare bits and these bits
have proven to be very valuable over time. With ASN.1, you have to
know in advance where you want extensibility so that you use the right
ASN.1 constructs.

/js

-- 
Juergen Schoenwaelder    <http://www.informatik.uni-osnabrueck.de/schoenw/>