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Optimized Communication For Mobile Multimedia Collaboration Applications. CTS`05 St. Louis May 6 th 2005. Sangyoon Oh Community Grids Laboratory Indiana University [email protected]. Contents. Introduction Related Works Handheld Flexible Representation Examples and Experiments - PowerPoint PPT Presentation
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Optimized Communication For Mobile Multimedia
Collaboration Applications
Sangyoon OhCommunity Grids Laboratory
Indiana [email protected]
CTS`05 St. Louis May 6th 2005
2
Contents
Introduction Related Works Handheld Flexible Representation Examples and Experiments Conclusion
Introduction
4
Why Interesting?
Prospective of popularity• Recent prominent data sharing: mobile
computing and other distributed system.
• SOAP Interoperability Connects disparate and distributed resources.
• Open Standard Community (W3C), Industry (Nokia, Sun, etc)• Binary Interchange of XML Infoset Workshop (Sep.
2003).
5
Problems
Possible performance overheads in Web services
• XML needs considerable resources for transmitting and parsing.
• Information storing in textual format
• XML’s descriptive tags and structure (increasing size)
Add parsing and transmission overheads.
Mobile environment
• Battery-constraint, limited computation
• High-latency, intermittent communication Compression of XML (GZip XML) would increase a
processing time and size of small message
6
Proposal of Flexible Representation
Purpose of Research:To design and develop an optimized communication framework preserving SOAP semantics for mobile computing.
Characteristics of research• Separate data presentation format and data content
• Loss of self description
• Saving parsing computation and data binding >> Latency Saving
High latency of cellular network
Related Works
8
Classification of SOAP Alternatives Some data don’t fit in XML serialization
: MTOM/XOP• Media data
• Standard format with compression
• JPEG, GIF, MP3
• Data that include digital signature• Binary integrity would not be preserved after serializing into
textual format Some application domains use a binary representation to
avoid verbose XML encoding. Fast Web Services/Fast Infoset, Extreme! Lab• Send pre-parse data over binary communication
9
Summary of projects
Extreme! Lab MTOM/XOPFast Web Services
Properties
Negotiation,
Binary Application Protocols
Support binary contents
GZip for XML
Target Scientific Data
Media File, Data that
includes digital signature
Java Application
(No changes on Application level)
Lack of mobile issues
QoS
Performance,
Optimized message
scheme for
in-memory representation
Fast Infoset is not interoperable,
QoS
Handheld Flexible Representation
11
Flexible Representation in general Using optimized data representation to improve
communication performances preserving SOAP semantics• Binary format stream• Negotiation• Quality of Service (reliability and security)
Imposing XML problems • Hard to address on individual message, but appears to be possible to
combine SOAP structure and binary format in stream processing. Work best for a stream
• Designed for high-frequency small messages.• Sharing message structure and WSDL information.• SOAP headers are largely unchanged.
12
Example of Filtering Data Representation
<wb:wireline>
<wb:points>
<wb:x>0</wb:x>
<wb:y>0</wb:y>
</wb:points>
.....
<wb:points>
<wb:x>100</wb:x>
<wb:y>100</wb:y>
</wb:points>
</wb:wireline>
<xs:complexType name="Wireline">
<xs:annotation>
<xs:appinfo>
<representation repType="binary“
byteOrder="bigEndian"/>
</xs:appinfo>
</xs:annotation>
<xs:sequence minOccurs="number of points"
maxOccurs="number of points">
<xs:element name="x" type="dfdl:binaryInt"/>
<xs:element name="y" type="dfdl:binaryInt"/>
</xs:sequence>
</xs:complexType>
(XML Representation) (DFDL Description)
13
Simple Scenario with negotiation1. Mobile device which is capable
of Flexible Representation initiates a negotiation with the mobile gateway.
2. SOAP message for negotiation is sent over the conventional SOAP.
3. mobile gateway responds to the negotiation request with its capability in the SOAP message.
4. response with message template/XML schema and quality of service issues.
5. agreed message format (Flexible Representation of SOAP Infoset) throughout the session.
Web Services Interface(NaradaBrokering)
HHMSGateway
MediaServer
SessionServer
SOAP over NB
RTP over NB
HHFR
Mobile Device(Camera Application)
14
Software architecture ContextHandler
• Schema Parser - Data Structure generator • Stream Reader/Writer• Context server
• Stores SOAP header of initial message (negotiation request message)
• Message schema • URI of Flexible Representation Specification(<xmlna:hhfr=“http://grids.ucs.indiana.edu/hhms/FlexRep”>)
• Each ContextBlock has a pointer to URI to Context server.
Currently, Ad-hoc scheme to store context WS-Context or any community-specific.
15
Relationship among different forms of SOAP messages and their defining context
Context Mapping
Optimized Communication
Context Generation onFirst Message : Data Structure (Schema) SOAP Header Stream(Session) Info
Preferred View on Mobile Application(In Memory version of HHFR)
XML/SOAPfor
Interoperability Optional
HHFR
ContextHandle
Context Server
16
HHFR in GlobalMMCS
1. Up-streaming the captured Image• Periodically captured images are converted
into stream using JMF library.
2. Down-streaming Video Session• Porting the conventional GlobalMMCS client
on mobile.
• Filtering the frame rate and image size.
MMAPI (JRS 135) in J2ME MIDP 2.0
17
Snap Shots
Conclusion and Future Works
19
Conclusion and future works Conclusion
• Negotiation and byte stream which is preserving SOAP infoset help to overcome possible performance overhead of mobile web services
• Help the integration of mobile device and collaboration systems in web services.
Future works• QoS Handler
• Reliable Messaging – WS-WRM• Security – Light weight security model
• Up-stream client porting on mobile
Appendix
21
Current status of 3G in the US
Cingular GPRS Cingular EDGE Cingular UMTS Verizon EV-DO
Rate56kbps (max.)30~40 kbps
120kbps (aver.)
Download:384kbps (max.)290kbps (aver.)
Upload:56kbps
Download:300~500kbps
Upload:90kbps
Coverage Nation-wide
Nation-wide (except
Montana, Dakotas and
Virginia)
Only six cities32 cities
(expensive plans)
Voice and data
-- -- Simultaneous
usage--
22
Wireless Tech. Comparison
Bandwidth Comparison of IR, WLAN and Bluetooth
Serial Infrared 115.2kbps
Bluetooth 1.1 723.1 kbps
Bluetooth 2.0 2.1 Mbps
802.11b 11Mbps
802.11g 54 Mbps
23
Handheld Messaging Service General mobile
communication framework by CGL
Provides a core pub/sub API for mobile application.• Lightweight user library
• Server-side gateway
• TCP and HTTP transport HHFR is a part
of HHMS
101
102
103
104
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
Payload (byte)
Ro
un
d T
rip
Tim
e (s
ec)
HHMSRPC
100
101
102
0
50
100
150
200
250
300
350
400
450
Number of Clients
Ro
un
d T
rip
Tim
e (m
sec
)
Pub/SubRPC
24
GlobalMMCS architecture
NaradaBrokeringXGSPClients
MediaServer
SessionServer
NB Link
RTP Link
XGSPGateways
(H.323, SIP,Streaming,
HHMS)
H.323, SIP,Streaming,
MobileClients
AccessGridVenues
WebServer
Client - GatewayCommunication