T-110.5140 Network Application Frameworks and XML Mobile Middleware 12.3.2007 Sasu Tarkoma

1. T-110.5140 Network Application Frameworks and XML Mobile Middleware12.3.2007Sasu Tarkoma

2. Contents • Mobile Middleware • Motivation • Examples • Summary

3. Mobile Middleware I • Middleware is typically designed and implemented for fixed-network hosts • High bandwidth, low latency, reliable communication • Persistent storage and sufficient computing power • No mobility • Mobile environment requires new solutions • Existing middleware services do not scale • Previous lectures: mobility is challenging • Small devices / embedded systems pose totally different challenges

4. Mobile Middleware II • Goals for middleware: • fault-tolerance, adaptability, heterogeneity,scalability, resource sharing • Mobile middleware • dynamically changing context • decoupled • events, tuple spaces • Basic solution for wireless • Use a proxy

5. Reflection • In general, middleware provides transparency to the underlying conditions • Location transparency in RPC/RMI • In mobile environments this is not always desired • Sometimes we need to know about location changes, QoS changes, etc. • Requirement for reflective middleware • Should expose APIs for querying / changing important parameters • Under development

6. Objects Secure mobile XML routing WAE Middleware XML IPv6 mobility, HIP .NET J2ME Security Mobility NAF Symbian Wireless CORBA Plain IPv4 MIP

7. Examples • WAE • J2ME • Wireless CORBA • Fuego

8. WAE • Wireless Application Environment (WAE) • A suite of protocols and specifications for optimizing data transfer for wireless communication • WAP stack • Focus on binary transmission • Protocols • WSP (Wireless Session Protocol) • HTTP replacement, “compressed” • WTP (Wireless Transaction Protocol) • Request/response, more efficient than TCP • WTLS (Wireless Transport Layer Security) • Based on TLS, may not be end-to-end with a gateway • WDP (Wireless Datagram Protocol) • UDP replacement

9. HTML/JS HTTP TLS - SSL TCP/IP UDP/IP Comparison WAE Other Session Layer (WSP) Transaction Layer (WTP) Security Layer (WTSL) Transport Layer (WDP,UDP) Bearers: SMS,CDMA,..

10. WAE: current status • WAP Forum now in OMA (Open Mobile Alliance) • WAP 2.0, is a re-engineering of WAP using a cut-down version of XHTML with end-to-end HTTP • Gateway and custom protocol suite is optional. • WAP used by many handsets • 1.2 version introduced WAP Push (typically using an SMS message) • Typically versatile networking stacks with also IPv6 support

11. Java 2 Platform Micro Edition (J2ME) • Java for consumer electronics and embedded devices • A virtual machine and a set of APIs • Configurations and profiles • Configurations • two-low level APIs and optimized VMs • CDC, CLDC • Profiles • API specification on top of a configuration for complete runtime • CLDC: MIDP • CDC: Foundation, Personal Basis, Personal • Specify both APIs and Configurations • Profiles defined using Java Community Process (JCP)

12. Source: http://developers.sun.com/techtopics/mobility/getstart/articles/survey/

13. J2ME optional packages • JSR 172: J2ME Web Services Specification • Content Handler API (CHAPI) JSR 211 • allows the invocation of J2ME platform applications from native applications and vice versa • Security and Trust Services JSR-177 • J2ME Client Provisioning JSR-124 • J2ME Client Provisioning Specification defines a server partitioning standard for provisioning applications. • Mobile Media API JSR-135

14. CLDC Technology • Connected Limited Device Configuration (CLDC); JSR 30, JSR 139 • Mobile Information Device Profile (MIDP); JSR 37, JSR 118 • Information Module Profile, (IMP); JSR 195 • Java Technology for the Wireless Industry, (JTWI); JSR 185 • Wireless Messaging API (WMA); JSR 120, JSR 205 • Mobile Media API (MMAPI); JSR 135 • Location API for J2ME; JSR 179 • SIP API for J2ME; JSR 180 • FileConnection and PIM API (JSR-75) • Security and Trust Services API for J2ME, (SATSA); JSR-177 • Mobile 3D Graphics; JSR-184 • J2ME Web Services APIs, (WSA); JSR 172 • Bluetooth API (JSR-82, Motorola, Java Partner Site) • J2ME Content Handler API, (CHAPI); JSR 211

15. CDC Technology • Connected Device Configuration (CDC); JSR 36, JSR 218 • Foundation Profile, (FP); JSR 46, JSR 218 • Personal Basis Profile, (PBP); JSR 129, JSR 217 • Personal Profile, (PP); JSR 62, JSR 216 • J2ME RMI Optional Package, (RMI OP); JSR 66 • JDBC Optional Package for CDC/Foundation Profile API; JSR 169 • Java TV API; JSR 927 • Java Secure Socket Extension for Connected Device Configuration (JSSE)

16. Wireless CORBA • CORBA does not support accessing mobile objects or wireless communication • Wireless CORBA specification • Three basic requirements • Invocations from mobile objects • Invocations to mobile objects • Wireless communication • Home bridge • Access bridges • Tunnelling over wireless • Handoff protocols

17. Mobile IP vs. WCORBA • MIP addresses host mobility, not object mobility • MIP does not specifically support wireless protocols • MIP hides all handoff events • location-aware services difficult to implement

18. Architecture • Redirects requests for • services on the terminal • Keeps track of the current • access bridge • Abstract transport-independent • tunnel for GIOP messages • Concrete tunnels for TCP/IP, • UDP/IP and WAP WDP. • Protocol requires reliable and • ordered delivery • Other side end of the Access Bridge • Encapsulate/decapsulates msgs • Generates mobility events • Encapsulates, forwards or ignores • incoming GIOP messages • Decapsulates and forwards • messages from the GIOP tunnel • Generates mobility events • Lists available services

19. Handoffs • Network initiated handoff • started by an external application • optional to support make-before-break • Terminal initiated handoff • terminal discovered a new Access Bridge • make-before-break is required • Access recovery • The Home Location Agent is updated • Old Access Bridges are informed • Mobility events are generated in the visited domain and the terminal domain

20. Network Initiated Handoff

21. Fuego Core (HIIT) • Mobile and wireless environments have different requirements than desktop systems • User mobility, terminal mobility, connectivity, device characteristics, dynamic environments • Vision: A service application is distributed among various application servers, network elements and terminals • Three year Tekes project (2002-2004) • Industrial partners: Nokia, TeliaSonera, Elisa, Ericsson, Movial • Open source software • Demonstration at WMCSA 2004

22. Fuego Architecture • The Fuego middleware service set for mobile computing • Data communication • Efficient wireless SOAP • Efficient content-based routing (asynchronous events) • Data synchronization • 3-way XML document merging • XML-aware distributed file system • Applications • Presence service, mobile ticker, image-album

24. Automatic reconciliation of XML documents Optimized storage of XML Ad-hoc file sharing Integrates with existing file systems (NFS) Expressive async. communication Content-based routing using filters Event buffering / mobility support Support for context-aware operation Presence service based on events Control of presence attribute visibility Efficient sync/async messaging Efficient XML serialization Persistent connections across mobility Reliable messaging Multiplexing multiple connections on TCP Prioritization of connections End-to-end authentication of hosts Encryption of network traffic using IPsec Mobility and multihoming support Resilient sockets

25. FUEGO DEMO

26. Summary • Mobile middleware • Desktop middleware not usable on small, mobile devices • Special solutions are needed • J2ME, WAE, Wireless CORBA, .. • Current trend • Flexibility, decoupled nature • Convergence / unification