Article View: comp.protocols.iso.x400
Article #540Re: DATA Compression and X400 standards
From: Peter Vanderbilt
Date: Thu, 15 Nov 1990 18:17
Date: Thu, 15 Nov 1990 18:17
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1680 bytes
Assuming that compression of P2 body parts is a good thing, is there a standard mechanism to use for identifying compression? The simpliest mechanism is to just use an external body part with a different object id (OID) for each different compression. Alternatively, one could use the parameters part with a field to indicate what kind of compression is used, where each compression algorithm is assigned an OID. The first mechanism has the problem that it requires "M*N" OIDs -- an OID has to be allocated (and configured) for each pair of data type and compression algorithm. The second mechanism only requires "M+N" OIDs -- one for each data type and one for each compression algorithm. But the second mechanism has the problem that it requires wide-spread implementation to achieve the desired independence -- which seems like a major hurdle. Does anybody have info on whether the standards people considered body part compression and, if so, how they expected it to be implemented? Is anyone implementing it currently and, if so, how? (Along the lines of the second mechanism, in practice it appears to be useful to carry an identifying string with a body part -- is there any hope that implementors would agree to a standard way to carry labels in the parameters part?) Pete
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!usc!orion.oac.uci.edu!ucivax!gateway From: pv@Eng.Sun.COM (Peter Vanderbilt) Newsgroups: comp.protocols.iso.x400 Subject: Re: DATA Compression and X400 standards Message-ID: <9011151813.AA14225@polya.Eng.Sun.COM> Date: 15 Nov 90 18:17:04 GMT Lines: 28 Approved: usenet@ICS.UCI.EDU