RIM based Wireless Internet Appliances

Our client was developing a Wireless Internet Appliance for home use. The appliance is managed via a web interface supported via a multi-tiered server architecture. Actions by the user are reflected in commands and data sent to the appliance. Conversely, interactions with the appliance cause actions in the back end servers, and notifications to the user(s) of the appliance, and other parties as well.

Communications with the appliance were to be secure, and with the RIM based solution, an X.25 Mobitex network connection needed to be established and maintained.

SilkSpeed's Role

SilkSpeed's role in this project was multifaceted: our experience in the development of embedded and communications applications was needed for the development of the appliance's own application; our knowledge of cryptographic systems, and the means and mechanisms of securing information was needed for the communications security requirements. Finally, SilkSpeed's experience designing and developing database backed Java applications, and experience with Java server technology brought in capabilities the project lacked.

RimOS

The appliance was implemented using the RimOS facilities for Interprocess Communication, memory management, radio communications, and device control. Six separate applications implemented various capabilities for the appliance, allowing pluggable and testable interfaces. One of these applications was a regression test, used to test the other applications in black box fashion.

SilkSpeed is quite familiar with the technical aspects and details of developing applications for RIM devices.

Mobitex Transport Layer and Cryptographic Services

The Mobitex network used by RIM products, and the Client needed a direct X.25 link to the Mobitex network. Further, since Mobitex is a peer to peer network, and the RIM devices themselves did not support Internet Protocols (UDP/TCP/IP), SilkSpeed developed the wireless transport software to adapt the short packet length Mobitex network to the IP network the server side components expected. This included SAR (Segmentation and Reassembly) of long messages and message bundling for efficient transport.

Also, since Mobitex network traffic has no data security provisions, SilkSpeed implemented a cryptographic solution based on RFC 1991 (PGP Message Exchange) to provide data security. As part of this process, SilkSpeed wrote supporting documentation for data security during all phases of the product life cycle, from Public Key creation during the manufacturing process to session key management and life cycle.

Transaction Protocol

In addition to the security elements required, the nature of the application demanded a Transaction Protocol to guarantee the reception, processing, and accounting of individual transactions across the network. Since the devices were battery operated, and could be deployed in marginal Mobitex network conditions, the system needed to correctly deal with all of the device and network conditions that could result.

XML based Menu System

The User Interface of the appliance was still evolving during development, and as business needs and partner relationships developed, User Interface content would be modified. Rather than embedding the menus and resulting operations in software, SilkSpeed implemented an XML Micro-Browser for the appliance, permitting menu content to be developed and tested on a desktop, and then deployed to the appliance. The XML DTD for the menus was loosely based on WML, and had binary extensions similar to WBXML.

Embedded Systems Development

Embedded Systems development is a discipline within the software development arena that has requirements all its own. These include live or over the air upgrades, unique memory management concerns, the use of unique Operating Systems, such as VxWorks, QNX, eCos, and possibly no operating system at all, which is common in the phone handset world.

SilkSpeed has a wealth of experience with embedded software development, and has particular expertise with communications and control application development.