approaches John Larmouth ITUT and ISOIEC ASN1 Rapporteur jlarmouthbtinternetcom Terminology has changed over time Markup languages Abstract Syntax and Concrete Syntax Abstract syntax notation and encodings ID: 914858
Download Presentation The PPT/PDF document "Describing and serializing structured d..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Describing and serializing structured data – A history and comparison of approaches
John Larmouth
ITU-T and ISO/IEC ASN.1 Rapporteur
j.larmouth@btinternet.com
Slide2Terminology has changed over timeMarkup languagesAbstract Syntax and Concrete SyntaxAbstract syntax notation and encodingsSchema definitionDescribing and serializing structured data
The
terms
all mean roughly the same thing!That is the main message from this tutorialIn the 1980s, it was sexy to talk about Abstract Syntax and encodings"Today it is sexy to talk about describing and serializing structure data
Slide3What is structured data?There is a general recognition that we are talking about data that can be best described using basic primitives like integers and booleans and stringsAnd “structuring” (with various names) using sequence, sequence of (repetitions), and choice
Slide4ASN.1 has developed over time (1)Developments to meet user demandsAll added immense richness, but inevitably more to be learned if you need the richnessDescription of structured data was extended to include information object classes, bringing with it much greater use of object identifiers and the need for the OID repository – so much so that OIDs have a life of their own, and a tree structure
Slide5ASN.1 has developed over time (2)Description of structured data was extended to include addition of constraints, which were visible for encoding rules (bringing ASN.1 more into line with programming languages
Parameterization of the basic notation was introduced (but not heavily used)
Slide6ASN.1 has developed over time (3)More encoding rules were added, some becoming very popular (e.g. PER)
Encoding control notation
was introduced (a substantial new topic, but not much used (?) )
Object identifier resolution using DNS was introduced – still in its gestation period in 2012, but very important
Slide7ASN.1 has developed over time (4)Fast web services and Fast Infoset were introduced, targeting the “XML heart-land”Competition with EXI became an issue – still not fully resolved.Today there is increasing competition on the notation to be used for structured data definition and its serialization/encodings – discussion later
Slide8The bottom lineThrough-out all of this, ASN.1 has always been, and still is,
the
ITU-T
Recommendation for the description and serialization of structured
data
Slide9Acronyms and standard names – you cannot avoid them (1)!SGMLASN.1TLVHTML, XMLXSD, Relax NGPER, XEROIDs
Slide10Acronyms and standard names – you cannot avoid them (2)!JSON (RFC 4627) and BSONGoogle Protocol BuffersRFC 3072, RFC 4506YAMLThriftETCHHadoop
Slide11When will I stop?Some of you may be leaving the room!I just want to do a little historical stuff, and then to invite some discussion on things todayI know that some groups are investigating other notations and encodingsI believe that in most cases they have decided to stay with ASN.1. I would like to invite comments shortly.
Slide12The 1960s to early 1980sPeople used typewriters!Physical cut and past (I have still scissors from those days!) was the way standards were developed! (some others in this room also did!)Markup languages were developed (Tex and Latex, for example)Immensely important as the basis for future work
Slide13The 1980s – a heady time (1)Led into IBM’s seminal work on SGML, which led to HTML from CERN, and in due course to XMLThese were all essentially mark-ups of content (encoding rules), not structured data definition.OSI badly needed a way of describing the structured data in protocols.
Slide14The 1980s – a heady time (2)I don’t want to waste your time too much on history, but I have to mention Doug Steedman and Jim White (see other sources of descriptionASN.1 became established – there was no real competitor!OSI badly needed a way of describing the structured data in protocols. ASN.1 emerged from Courier work in Rank Xerox.
Slide15The 1980s – a heady time (3)Papers at that time were addressing “OSI versus SNA”.They later changed to OSI versus TCP/IP.We all know which won!But ASN.1 remained as the notation of choice for the definition of structured data
Slide16The 1990s – stability? (maybe not!)The XML people introduced XSD. Standardise a mapping from XSD to ASN.1? Or vice-versa? Or a round-trip mapping?“You map from a competitor notation to yours, not vice-versa” – bad advice which led to people using XSD as the schema definition of choice, relying on the mapping to ASN.1 for ASN.1 binary encodings.XML encoding rules for ASN.1 (XER)
Slide17And to the 2000s – it is up in the air again!We have a plethora of new options: JSON and BSONGoogle Protocol BuffersCandle markupBencodeYAML
Hadoop
Thrift
What have I missed?
Slide18ASN.1 remains the choice for …Big DataSatellie (Europe’s Galileo project)Aviation (3GPPP 4G, LTEAdvanced online gamingWind turbines
Personal health records
Smart highways
Electrical smart grid
Slide19Discussion invited please!I
am done!