XFSP : Cross Format Schema ProtocolFlexible Networking via

XML-Defined Packet Payloads

Ltjg. Ekrem Serin

TU Navy

THE MOVES INSTITUTE 2

XFSP: Cross-Format Schema Protocol

Idea Extensible and Flexible Application Layer Protocol

Syntax Transactions via XML XML Serialization / Deserialization

Depending on Schema Knowledge

Target Area Net-VEs Web-based Applications XML-RPC

SOAP

THE MOVES INSTITUTE 3

XFSPBenefits

Schemas are tailored No need to hard code protocol syntax,

Compact XML, Platform-Independent (JAVA, XML), Hybrid Platform Communication

Application – Application Application - Web

Run-time Extensible Can be loaded or changed

THE MOVES INSTITUTE 4

XFSP

XML Data

XML Data XML

Data

Schema

Schema

Schema

Schema

Schema

Schema

Application

THE MOVES INSTITUTE 5

What is XML?

- A Tree- Where it can be traversed in pre-order, in-order

and post-order manners.

<?xml version="1.0" encoding="UTF-8"?><protocol xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="example.xsd">

<location x="3.45" y="56.72" z="-10.1"/><header>

<exerciseID>1</exerciseID><version>1</version><pdutype>2</pdutype>

</header><velocity x="1.0" y="0.0" z="-0.7"/>

</protocol>

THE MOVES INSTITUTE 6

XML Tree

version exerciseID

pduType

location

x

protocol

y z

header velocity

x y z

3.45 56.72

-10.1

1

2

11.0

0.0

-0.7

THE MOVES INSTITUTE 7

Parser APIs

- With Java 1.4 SAX API is provided- Start and End of Elements (event based)- Element names are created by the user- No tree representation

- JDOM- Tree Representation- Adapters (JAXP, Crimson, Oracle, Xerces,

XML4J)- Outputters (Text)

THE MOVES INSTITUTE 8

Parser APIs

- DOM4J- Tree Representation- Adapters- Outputters- Custom-type Object Binding- XPath Addressing

THE MOVES INSTITUTE 9

Schema

- A Protocol- Where it defines the data structure of the

XML documents for end-users.- Agreement.- Set of Rules.

THE MOVES INSTITUTE 10

Schema

THE MOVES INSTITUTE 11

AlgorithmXML Serialization

Parse the schema document. Create a look-up table for attributes and elements. Assign unique numbers to the elements and

attributes. Walk through the XML tree and put each element

and attribute into the output stream by replacing their tag names with numbers.

Preserves the content in binary form as compact XML.

THE MOVES INSTITUTE 12

Schema Parsing

Name Start Tag Number End Tag Number Datatype

/protocol 10 11 Null

/protocol/header 12 13 ComplexType

/protocol/location 14 15 ComplexType

/protocol/velocity 16 17 ComplexType

/protocol/header/version 18 19 XSDShort

/protocol/header/exerciseID 20 21 XSDByte

/protocol/header/pduType 22 23 XSDInteger

THE MOVES INSTITUTE 13

Schema Parsing

Name Tag Number Datatype

/protocol/location/@x 24 XSDDouble

/protocol/location/@y 25 XSDDouble

/protocol/location/@z 26 XSDDouble

/protocol/velocity/@x 27 XSDFloat

/protocol/velocity/@y 28 XSDFloat

/protocol/velocity/@z 29 XSDFloat

THE MOVES INSTITUTE 14

XML Serialization<?xml version="1.0" encoding="UTF-8"?><10 > <14 24="3.45" 25="56.72" 26="-10.1" 15> <12>

<20>1<21><18>1<19><22>2<23>

<13> <16 27="1.0" 28="0.0" 29="-0.7" 17><11>

10 14 1 24 3.45 25 56.72 26 -10.1 2 15

12 20 0 1 21 18 0 1 19 22 0

2 23 13 16 1 27 1.0 28 1.0 29 -0.7

2 17 11

THE MOVES INSTITUTE 15

Compression

389 383 378

118

0

50

100

150

200

250

300

350

400

450

1 2 3 4

In B

ytes

File JDOM DOM4J XFSP

THE MOVES INSTITUTE 16

Algorithm

XML Deserialization Read tag numbers from the stream. Retrieve element or attribute associated

with that number. Read the data. Create the elements, attributes and bind

data to them. Rebuild the XML tree. Retrieve data from the tree when needed.

THE MOVES INSTITUTE 17

Where to Use ?

- SOAP (Simple Object Access Protocol)- XML envelope for transactions- Send it compressed

<s:Envelope xmlns:s= “http://schemas.xmlsoap.org/soap/envelope/” xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance” xmlns:xsd="http://www.w3.org/1999/XMLSchema”> <s:Body> <m:sayHello xmlns:m=‘urn:Example’>

<name xsi:type=‘xsd:string’>Ekrem</name> </m:sayHello> </s:Body></s:Envelope>

THE MOVES INSTITUTE 18

Where to use ?

Application Code

Web

Service

Application Client

Platform and language specific

communication

Platform and language agnostic

communication

THE MOVES INSTITUTE 19

Binary X3D

- X3D is an XML file format describes a scene graph,

- Fairly heavyweight for Network Transmission,

- Can be compressed by designed algorithm,

- GZip Streams are used for further compression.

THE MOVES INSTITUTE 20

X3D Compression

THE MOVES INSTITUTE 21

X3D Compression / Decompression

Serializer

X3D Schema

X3D File B3D GZIP Stream

B3Z

GZIP Stream

X3D Schema

B3Z File B3D Deserializer X3D

THE MOVES INSTITUTE 22

Comparison in Kbytes

129

111

84

34 3329

0

20

40

60

80

100

120

140

x3d wrl b3d zip_x3d zip_wrl b3z

File Formats

Siz

e in

KB

yte

THE MOVES INSTITUTE 23

Comparison in Percentage

14

34

73 7478

0

10

20

30

40

50

60

70

80

90

wrl b3d zip_x3d zip_wrl b3z

File Formats

Sav

ings

in %

THE MOVES INSTITUTE 24

Rendering B3Z File

GZIP Stream

X3D Schema

B3Z File B3D File Deserializer

VRML97

X3D Stylesheet

Xj3D Browser

Transformer

X3D File

THE MOVES INSTITUTE 25

Rendering B3Z File

THE MOVES INSTITUTE 26

NPSNET-V

NPSNET-V : Run-time Extensible Networked Virtual Environment.

XFSP is embedded into the NPSNET-V as a network module. Networking is run-time extensible.

Packet formats are defined by using XML-Schema which is tailored to point the application layer protocol.

Framework is not targeted to define the semantics between protocol and application.

THE MOVES INSTITUTE 27

XFSP / ESPDU Packet Format

THE MOVES INSTITUTE 28

Detonation PDU Packet Format

THE MOVES INSTITUTE 29

Run-time Extensibility- ESPDU is loaded, no knowledge of Detonation PDU Syntax.

THE MOVES INSTITUTE 30

Run-time Extensibility- Detonation PDU Protocol is loaded at run-time.

THE MOVES INSTITUTE 31

XFSP

Demo / Questions ?