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• IEEE 802.21 MEDIA INDEPENDENT HANDOVER

• DCN:21-05-0407-03-0000

• Title: Integration of XML and TLV

• Date Submitted: January, 9, 2006

• Presented at IEEE 802.21 session in Vancouver

• Authors or Source(s):

•  Yoshihiro Ohba, Kenichi Taniuchi and Subir Das

• Abstract: This document describes two methods for converting XML 1.0 data to TLV format. The two methods and XML 1.0 are compared in terms of number of encoded octets and processing time for three typical query types.

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IEEE 802.21 presentation release statements

• This document has been prepared to assist the IEEE 802.21 Working Group. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.

• The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.21.

• The contributor is familiar with IEEE patent policy, as outlined in Section 6.3 of the IEEE-SA Standards Board Operations Manual <http://standards.ieee.org/guides/opman/sect6.html#6.3> and in Understanding Patent Issues During IEEE Standards Development http://standards.ieee.org/board/pat/guide.html> 

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Information Service Properties

• Information Service representation and Information query/exchange shall be

• Extensible: • The specification shall be able to support future PHY/MAC

technology, without changing the 802.21 specification itself every time a new PHY/MAC technology is invented

• Flexible: • The specification shall be able to support various types of queries to

be useful for different handover mechanisms, protocols, algorithms and policies.

• Efficient:• The specification shall avoid unnecessary information

query/exchange and should have less information encoding overhead

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A Possible Approach

• Schema-based semantic query with binary encoding

• Schema provides extensibility

• Semantic query provides flexibility and query efficiency

• Binary encoding provides encoding efficiency

How can we achieve all of above functionalities?

It is evident that only by integrating XML and TLV, we can

achieve best of each solution

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Candidate Solutions

• XML provides schema-based semantic query • But needs to send more bits over the air if we use native XML 1.0

format

• TLV provides binary encoding• But does not provide a standard query language for semantic query

It is evident that only by integrating XML and TLV, we can achieve best of each solution

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How Can We integrate?• Possible approach : XML binary representation

• Convert XML data contained in query result into TLV• Two example conversion methods

• Method A: Applicable to any XML data• Alias-based conversion

• Convert XML namespace names to integers• Convert XML tag names to integers• Convert XML attribute names to integers• Convert ENTRY names to integers

• Dynamic integer mapping• Mappings are carried with data

• Method B: Applicable to a particular query language• Semantic bundling

• Two or more semantically -related XML tags are mapped to a single integer for further optimization• Taking advantage of the knowledge of the query language syntax

• Apply Method A for other operations

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Method A

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TLV Format for XML binary encoding

0x1= STR

0x2= XMLVER

0x3 = DOCTYPE0x4 = ENTDEF0x5 = DOC0x6 = NSDEF 0x7 = BASE0x8 = TAGDEF0x9 = ATRDEF0xa = ENT0xb = NS0xc = TAG0xd = ATR0xe = STRALDEF

Type Length Value

Octets: 1 2 Variable

0xf = STRAL0x10 = YES0x11 = NO0x12 = BLANKNODE0x13 = RDFTRIPLES0x14 = VARIABLE0x15 = RESULT…

Type field values

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STR TLV

• Value field contains an octet string

Octets:

Octet String

Variable

Length0x1

21

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STRALDEF TLV

• Value field: String Alias Number and Octet String

String Alias Number

Octets: 2

Octet String

Variable

Length0xe

21

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STRAL TLV

• Value field:

String AliasNumber

Octets: 2

Length0xf

21

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XMLVER TLV• Corresponds to <?xml version=“…”> tag

• Value field contains the version string

• In case of <?xml version=“1.0”>, XMLVER TLV can be omitted

Octet String

Octets: 2

Length0x2

21

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DOCTYPE TLV

• Corresponds to <!DOCTYPE document_type> commentary tag

• Value field contains the document_type string

STR TLV

Octets: 2

Length0x3

21

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ENTDEF TLV

• Corresponds to “<!ENTRY entry_name entry_value>”

EntryNumber

STR TLV (Entry name)

Octets: 2 Variable

STR TLV (Entry value)

Variable

Length0x4

21

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DOC TLV

• Corresponds to the first non-commentary tag

List of NSDEF TLVs(option)

BASE Value(Octet String)

Octets: VariableVariable

Length0x5

21

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NSDEF TLV

• Corresponds to “xmlns:namespace_name” attribute

NSNumber

STR TLV(NS name [Optional])

Octets: 2 Variable

STR TLV or ENT TLV(NS value)

Variable

Length0x6

21

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BASE TLV

• Corresponds to “xmln:base” attribute

Octets:

STR TLV or ENT TLV

Variable

Length0x7

21

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TAGDEF TLV

• Corresponds to the non-commentary tags except for the first one

TagNumber

Octets: 2

Tag Name(Octet String)

Variable2

NS Number

If there is no explicit namespece, then NS Number value is 0 (zero)

Length0x8

21

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Predefined Tag Numbers (1..999)

• sparql= 1

• head = 2

• variable = 3

• results = 4

• result = 5

• binding = 6

• literal = 7

• boolean = 8

TAGDEF TLV is not needed for the above tags

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TAG TLV

• Corresponds to a non-commentary tag

TagNumber

Octets: 2

Zero or more ATR TLVs

Variable

Zero or more TAG TLVs or TAGDEFs or

ATRDEFs or STR TLV or STRAL TLV [OPTIONAL]

Variable

Length0xc

21

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ATRDEF TLV

• Corresponds to an attribute_name=attribute_value part in tag

AttributeNumber

Octets: 2

Attribute Name(Octet String)

Variable

Length0x9

21

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Predefined Attribute Numbers (1..999)

• name = 1

• datatype = 2

• ordered = 3

• distince = 4

ATRDEF TLV is not needed for the above attribute numbers

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ATR TLV

• Corresponds to an attribute_name=attribute_value part in tag

AttributeNumber

Octets: 2

STR TLV orSTRAL TLV

Variable2

Entry Number

If there is no explicit entry, then Entry Number value is 0 (zero)

Length0xd

21

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ENT TLV

Entry Number

Octets: 2

Length0xa

21

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NS TLV

NS Number

Octets: 2

Length0xb

21

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Type of query used in XML

• XML-based query language, e.g., SPARQL, has three types query:

• Construction query: used for sub-graph fetch• RDF triples are returned

• Selection query: used for selected bindings• pairs of variable names and values are returned

• Boolean query: Used for binary answer• “yes” or “no” is returned

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Example of a Construction query

• Query for obtaining IEs of a neighboring PoA

PREFIX mihbase: <http://www.mih.org/>CONSTRUCT ?s ?p ?oWHERE { GRAPH ?g1{ ?s ?p ?o ?x mihbase:poa ?poa. ?poa mihbase:poa-type 19 . ?poa mihbase:poa-id “aabbccddeeff” . }}

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Construction query result• Query result in XML 1.0 (1198 Bytes)

<?xml version="1.0"?>

<!DOCTYPE rdf:RDF [ <!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <!ENTITY rdfs "http://www.w3.org/2000/01/rdf-schema#"> <!ENTITY mihbase "http://www.mih.org/basic-schema#"> <!ENTITY base "http://mediaindependentinformationserver.org/" >

]><rdf:RDF xmlns:rdf="&rdf;" xmlns:rdfs="&rdfs;" xmlns:mihbase="&mihbase;" xml:base="&base;">

<rdf:Description rdf:about="&base;network2"> <rdf:type rdf:resource="&mihbase;Network"/> <mihbase:mdi> <rdf:Description> <mihbase:data-rate>54000</mihbase:data-rate> </rdf:Description>

• Query result in XML binary in TLV (680 Bytes)

[0x3][229][ [0x1][7]["rdf:RDF"] [0x4][54][1][ [0x1][3]["rdf"] [0x1][43]["http://www.w3.org/1999/02/22-rdf-syntax-ns#"] ] [0x4][49][2][ [0x1][4]["rdfs"] [0x1][37]["http://www.w3.org/2000/01/rdf-schema#"] ] [0x4][47][3][ [0x1][7]["mihbase"] [0x1][32]["http://www.mih.org/basic-schema#"] ] [0x4][57][4][ [0x1][4]["base"] [0x1][45]["http://mediaindependentinformationserver.org/"] ] ][0x5][61] [ [0x6][13][1][ [0x1][3]["rdf"] [0xa][2][1] ] [0x6][14][2][ [0x1][4]["rdfs"] [0xa][2][2]] [0x6][17][3][ [0x1][7]["mihbase"] [0xa][2][3]] [0x7][5][ [0xa][2][4]]]][0x8][15][1000][1]["Description"][0x9][9][1000][1]["about"]

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</mihbase:mdi> <mihbase:mii> <rdf:Description> <mihbase:poa> <rdf:Description> <mihbase:poa-type>19</mihbase:poa-type> <mihbase:poa-id>aabbccddeeff</mihbase:poa-id> </rdf:Description> </mihbase:poa> <mihbase:neighboring-poa> <rdf:Description> <mihbase:poa-type>19</mihbase:poa-type> <mihbase:poa-id>112233445566</mihbase:poa-id> </rdf:Description> </mihbase:neighboring-poa> <mihbase:neighboring-poa> <rdf:Description> <mihbase:poa-type>19</mihbase:poa-type> <mihbase:poa-id>0123456789ab</mihbase:poa-id> </rdf:Description> </mihbase:neighboring-poa> </rdf:Description> </mihbase:mii></rdf:Description>

</rdf:RDF>

[0xc][310][1000][ [0xd][15][1][ [0xa][2][4]["network2"] ] [0x8][8][1001][1]["type"] [0x9][12][1001][1]["resource"] [0xc][16][1001][ [0xd][11][1001][3]["Network"] ] [0x8][7][1002][3]["mdi"] [0xc][37][1002][ [0xc][32][1000][ [0x8][14][1003][0x1][9]["data-rate"] [0xc][10][1003][0x1][5][“54000”] ] ] [0x8][7][1004][3]["mii"] [0xc][182][1004][ [0xc][177][1000][ [0x8][7][1005][3]["poa"] [0xc][60][1000][ [0x8][12][1006][3]["poa-type"] [0xc][7][1006][0x1][2][“19”] [0x8][10][1007][3]["poa-id"] [0xc][17][1007][0x1][12]["aabbccddeeff"] ] [0x8][19][1008][3]["neighboring-poa"] [0xc][37][1008][ [0xc][32][1000][ [0xc][7][1006][0x1][2][“19”] [0xc][17][1007][0x1][12]["112233445566"] ] ] [0xc][37][1008][ [0xc][32][1000][ [0xc][7][1006][0x1][2][“19”] [0xc][17][1007][0x1][12]["0123456789ab"] ] ] ] ] ]

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Example of a Selection query• Query for obtaining neighboring PoA

PREFIX mihbase: <http://www.mih.org/>SELECT ?poa-idWHERE { ?mii mihbase:poa ?poa . ?poa mihbase:poa-id 123456789abc . ?mii mihbase:neighboring-poa ?neighboring-poa . ?neighboring-poa mihbase:poa-id ?poa-id .}

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Selection query result

<?xml version="1.0"?><sparql xmlns="http://www.w3.org/2005/sparql-results#"> <head> <variable name=”poa-id”/> </head> <results ordered=”false” distince=”false”> <result> <binding name=”poa-id”> <literal datatype="http://www.w3.org/2001/XMLSchema#hexBinary"> aabbccddeeff</literal></binding> </result> <result> <binding name=”poa-id”> <literal datatype=”http://www.w3.org/2001/XMLSchema#hexBinary”>112233445566</literal></binding> …….(more 8 poa-ids are written here) </rebult> </results></sparql >

[0xc][694][1][ [0x6][41][0][ [0x1][38]["http://www.w3.org/2005/sparqlresults#"]] [0xc][20][2][ [0xc][15][3][ [0x9][10][1][0]["poa-id"]]] [0xc][621][4][ [0x9][9][3][0]["false"][0x9][9][4][0]["false"] [0xc][97][5][ [0xc][15][6][ [0x9][10][1][0]["poa-id"]] [0xc][76][7][ [0xe][44][1][http://www.w3.org/2001/XMLSchema#hexBinary] [0x9][9][2][0][0xf][2][1] [0x1][12]["aabbccddeeff"]]] [0xc][52][5][ [0xc][15][6][ [0x9][10][1][0]["poa-id"]] [0xc][29][7][ [0x9][9][2][0][0xf][2][1] [0x1][12]["112233445566"]]]…(more 8 poa-ids are written here)]]

• Query result in XML 1.0 (1596 Bytes) • Query result in XML binary in TLV (694 Bytes)

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Example of a Boolean query

• Query for asking if a neighboring PoA is 802.11

PREFIX mihbase: <http://www.mih.org/>

ASK {?poa mihbase:poa-type 19 ; ?poa mihbase:poa-id “aabbccddeeff” }

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Boolean query result• Query result in XML 1.0 (153 Bytes)

<?xml version="1.0"?><sparql xmlns="http://www.w3.org/2005/06/sparqlResults"> <head></head> <results> <boolean>true</boolean> </results></sparql>

• Query result in XML binary in TLV (52 Bytes)

[0xc][49][1][0x6][44][1][0x1][39]["http://www.w3.org/2005/06/sparqlResults"] [0xc][2][2] [0xc][14][4] [0xc][9][8][0x1][4]["true"] ]

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Comparison of the formats

52

694

680

153

1596

1198

0 500 1000 1500 2000

Boolean query

Selection query

Construction query

Number of encoded bytes

Method A XML 1.0

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Method B

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TLV Format for XML binary encoding

0x1= STR

0x2= XMLVER

0x3 = DOCTYPE0x4 = ENTDEF0x5 = DOC0x6 = NSDEF 0x7 = BASE0x8 = TAGDEF0x9 = ATRDEF0xa = ENT0xb = NS0xc = TAG0xd = ATR0xe = STRALDEF

Type Length Value

Octets: 1 2 Variable

0xf = STRAL0x10 = YES0x11 = NO0x12 = BLANKNODE0x13 = RDFTRIPLES0x14 = VARIABLE0x15 = RESULT…

Type field values

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YES TLV

• Value field: NULL

• This TLV may be used for encoding result of “yes” for Boolean query of SPARQL.

• When this TLV is carried, other TLVs carried in the same query result can be omitted.

• Receiver which receives this TLV decodes it to an appropriate XML format for the corresponding SPARQL Query results.

Length(=0)0x10

21Octets:

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NO TLV

• Value field: NULL

• This TLV may be used for encoding result of “no” for Boolean query of SPARQL.

• When this TLV is carried, other TLVs carried in the same query result can be omitted.

• Receiver which receives this TLV decodes it to an appropriate XML format for the corresponding SPARQL Query results.

Length(=0)0x11

21Octets:

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BLANKNODE TLV

Length(=2)0x12

21Octets:

Blank Node Number

2

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RDFTRIPLES TLV

Length0x13

21Octets:

Zero or moreNS TLV (Optional)

(Subject)

Variable

BLANKNODE TLV orSTR TLV or

STRAL TLV (Subject)

Variable

Zero or moreNS TLV (Optional)

(Predicate)

Variable

BLANKNODE TLV orSTR TLV or

STRAL TLV (Predicate)

Variable

Zero or moreNS TLV (Optional)

(Object)

Variable

BLANKNODE TLV orSTR TLV or

STRAL TLV (Object)

Variable

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VARIABLE TLV

Length0x14

21Octets:

STR TLV

Variable

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RESULT TLV

Length0x15

21Octets:

NS TLV(OPTIONAL)

Variable

BLANKNODE TLV orSTR TLV or STRAL TLV

Variable

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Construction query result with SPARQL optimization

• (SPARQL Query Results XML Format) 1198 Bytes

<?xml version="1.0"?>

<!DOCTYPE rdf:RDF [ <!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <!ENTITY rdfs "http://www.w3.org/2000/01/rdf-schema#"> <!ENTITY mihbase "http://www.mih.org/basic-schema#"> <!ENTITY base "http://mediaindependentinformationserver.org/" >

]><rdf:RDF xmlns:rdf="&rdf;" xmlns:rdfs="&rdfs;" xmlns:mihbase="&mihbase;" xml:base="&base;">

<rdf:Description rdf:about="&base;network2"> <rdf:type rdf:resource="&mihbase;Network"/> <mihbase:mdi> <rdf:Description> <mihbase:data-rate>54000</mihbase:data-rate> </rdf:Description>

• (TLV) 587Bytes

[0x6][50][1][0x1][45]["http://mediaindependentinformationserver.org/"][0x6][37][2][0x1][32]["http://www.mih.org/basic-schema#"][0x6][48][3][0x1][43]["http://www.w3.org/1999/02/22-rdf-syntax-ns#"][0x13][43] [0xb][2][1][0x1][8]["network2"] [0xb][2][3][0x1][4]["type"] [0xb][2][2][0x1][7]["Network"] ][0x13][30] [0x12][2][1] [0xb][2][2][0x1][9]["data-rate"] [0x1][5]["54000"] ][0x13][32] [0xb][2][1][0x1][8]["network2"] [0xb][2][2][0x1][3]["mdi"] [0x12][2][1] ][0x13][26] [0x12][2][3] [0xb][2][2][0x1][8]["poa-type"] [0x1][2]["19"] ][0x13][34] [0x12][2][3] [0xb][2][2][0x1][6]["poa-id"] [0x1][12]["aabbccddeeff"] ]

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</mihbase:mdi> <mihbase:mii> <rdf:Description> <mihbase:poa> <rdf:Description> <mihbase:poa-type>19</mihbase:poa-type> <mihbase:poa-id>aabbccddeeff</mihbase:poa-id> </rdf:Description> </mihbase:poa> <mihbase:neighboring-poa> <rdf:Description> <mihbase:poa-type>19</mihbase:poa-type> <mihbase:poa-id>112233445566</mihbase:poa-id> </rdf:Description> </mihbase:neighboring-poa> <mihbase:neighboring-poa> <rdf:Description> <mihbase:poa-type>19</mihbase:poa-type> <mihbase:poa-id>0123456789ab</mihbase:poa-id> </rdf:Description> </mihbase:neighboring-poa> </rdf:Description> </mihbase:mii></rdf:Description>

</rdf:RDF>

[0x13][21] [0x12][2][2] [0xb][2][2][0x1][3]["poa"] [0x12][2][3] ][0x13][26] [0x12][2][4] [0xb][2][2][0x1][8]["poa-type"] [0x1][2]["19"] ][0x13][34] [0x12][2][4] [0xb][2][2][0x1][6]["poa-id"] [0x1][12]["112233445566"] ][0x13][33] [0x12][2][2] [0xb][2][2][0x1][15]["neighboring-poa"] [0x12][2][4] ][0x13][26] [0x12][2][5] [0xb][2][2][0x1][8]["poa-type"] [0x1][2]["19"] ][0x13][34] [0x12][2][5] [0xb][2][2][0x1][6]["poa-id"] [0x1][12]["0123456789ab"] ][0x13][33] [0x12][2][2] [0xb][2][2][0x1][15]["neighboring-poa"] [0x12][2][5] ][0x13][32] [0xb][2][1][0x1][8]["network2"] [0xb][2][2][0x1][3]["mii"] [0x12][2][2] ]

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Selection query result with SPARQL optimization

• (SPARQL Query Results XML Format) 1596 Bytes

<?xml version="1.0"?><sparql xmlns="http://www.w3.org/2005/sparql-results#"> <head> <variable name=”poa-id”/> </head> <results ordered=”false” distince=”false”> <result> <binding name=”poa-id”> <literal datatype="http://www.w3.org/2001/XMLSchema#hexBinary"> aabbccddeeff</literal></binding> </result> <result> <binding name=”poa-id”> <literal datatype=”http://www.w3.org/2001/XMLSchema#hexBinary”>112233445566</literal></binding> …….(more 8 poa-ids are written here) </rebult> </results></sparql >

• (TLV) 192Bytes

[0x14][9][0x1][6]["poa-id"][0x15][15][0x1][12]["aabbccddeeff"][0x15][15][0x1][12]["112233445566"].....(more 8 poa-ids are written here)

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Boolean query result with SPARQL optimization

• (SPARQL Query Results XML Format) 153 Bytes

<?xml version="1.0"?><sparql xmlns="http://www.w3.org/2005/06/sparqlResults"> <head></head> <results> <boolean>true</boolean> </results></sparql>

• (TLV) 3Bytes

[0x10][0]

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Comparison of the formats

3

192

587

153

1596

1198

0 500 1000 1500 2000

Boolean query

Selection query

Construction query

Number of encoded bytes

Method B XML 1.0

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Comparison between Method A and Method B

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Comparison of the formats

150

290

413

3

192

587

52

694

680

153

1596

1198

0 500 1000 1500 2000

Boolean query

Selection query

Construction query

Number of encoded bytes

XML 1.0

Method A

Method B

gzip

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Two types of conversions

XML DOM

InternalData

BinaryData

Direct Conversion

3-Step Conversion

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Data conversion time measured on PDA (CPU: ARM 206MHz, OS: Linux)

Constuction Query

　 Method AMethod B

gunzip

Direct Conversion Binary(TLV) to Internal 7 TBD N/A

3Step Conversion

Binary to XML TBD TBD 15

XML to DOM 41 41 41

DOM to Internal 33 33 33

Total TBD TBD 89

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Backup

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Data conversion time for Method A measured on PC

Internal data: DOM (Document Object Model)CPU: Pentium-M 1.7GHzOS: Linux

•Construction queryInternal to XML : 1-2ms XML to TLV: 2-3ms

•Selection queryInternal to XML : 3ms XML to TLV: 3ms

•Boolean queryInternal to XML : 1ms XML to TLV: 2ms