8 Technical Reference Model

• [310101] Wireless / Mobile
• [310102] Platform Independent
• [310103] Platform Dependent

• [310201] Web Servers
• [310202] Media Servers
• [310203] Application Servers
• [310204] Portal Servers

• [310301] Integrated Development Environment (DE)
• [310302] Software Configuration Management
• [310303] Test Management
• [310304] Modelling

• 310401] Database
• [310402] Storage

• [310501] Servers / Computers
• [310502] Embedded< Technology Devices
• [310503] Peripherals
• [310504] Wide Area Network (WAN)
• [310505] Local Area Network (LAN)
• [310506] Network Devices / Standards
• [310507] Video

An example of wireless/mobile technology includes:

• Java 2 Platform, Micro Edition (J2ME): Sun's Java environment for devices. It promises a relatively portable environment for those using Java for other tiers of the architecture.

Examples of platform independent technologies include:

• Hypervisor: also called a virtual machine manager, is a program that allows multiple operating systems to share a single hardware host.
• Java 2 Platform Enterprise Edition (J2EE): Sun's J2EE and Microsoft's .Net are the two dominant distributed computing architecture frameworks. J2EE provides portability of a single language (Java) over multiple operating systems and hardware platforms
• Linux: an open source operating system that runs on multiple hardware platforms. With the ability to run on many platforms, including the PC and Macintosh, Linux has become an alternative to proprietary systems.
• Eclipse: a collection of open source projects built on the Equinox OSGi run-time.

Examples of platform dependent technologies include:

• Windows: Microsoft family of operating systems for personal computers.
• Mac OS: Apple's UNIX-based operating system based on industry standards.
• Net: Microsoft's .Net and Sun's J2EE are the two dominant distributed computing architecture frameworks. The .Net framework supports a wide range of languages but is primarily tied to the Microsoft Windows operating system and Intel hardware

Examples of web server technologies include:

• Apache: a widely used, public domain, UNIXbased web server from the Apache Group (www.apache.org). It is based on, and is a plugin replacement for, NCSA's HTTP server Version 1.3. The name came from a body of existing code and many 'patch files'
• Internet Information Server: web server software from Microsoft that runs under various versions of Microsoft Windows. It supports Netscape's SSL security protocol and turns a Windows-based PC into a website.

Examples of Media Servers include:

• Real Audio: streaming media server solution designed to supply desktop and mobile content
• Windows Media Services: part of Microsoft Windows Server editions, optimised to deliver streaming media and dynamic digital content over intranet and Internet delivery channels.

In an n-tier environment, a separate computer (application server) performs the business logic, although some part may still be handled by the user's machine.
Business Rules Engine are software systems that executes one or more business rules in a runtime production environment.

Examples of application servers include:

• IBM's Websphere Application Server
• Oracle Application Server

Examples of business rules engines include:

• IBM's Websphere ILOG JRules
• Oracle Business Rules: a component of Oracle Application Server
• Microsoft Business Rules Framework – a Microsoft .NET-compliant class library.

Examples of functions supporting software configuration management for which technical solutions may be available include:

• version management: refers to tracking and controlling versions of files. Version Management includes capabilities such as labelling, branching, merging, version content comparisons and security and permission management across version controlled projects
• defect tracking: refers to the identification, assignment and management of discovered defects within an application, product or solution. Defect tracking tools provide searchable defect data to identify urgent and related defects or bugs. The architecture should be built to facilitate the pushing of software patches across the enterprise
• issue management: refers to the management of business, technical and infrastructure issues throughout the entire life-cycle of a project
• task management: requirements, testing and issues assignments are transformed into prioritised tasks. Task Management tools provide automation features for managing, delivering, assigning, reminding and collaborating task management and execution
• change management: refers to the management of application code and content changes across the software development lifecycles
• deployment management: refers to the capability of software delivery to remote networked desktops, servers and mobile devices across an enterprise. Deployment automation tools provide centralised and accelerated delivery of applications to users via push technologies, eliminating the need for manual installation and configuration
• requirements management and traceability: consists of information discovery, capture, storage and dissemination. Requirements management reduces software development costs and associated risks through documenting, measuring and analysing deviations to project requirements. Traceability refers to tracking requirements artefacts to their source, and changes in requirements to include the impact analysis of the change. Requirements traceability is an integral component in quality software implementation and the management of document succession.

Examples of functions supporting test management for which technical solutions may be available include:

• functional testing: focuses on any requirements that can be traced directly to use cases (or business functions), business rules and design
• business cycle testing: refers to the emulation of activities performed over a period of time that is relevant to the application under test
• usability testing (508 Testing): refers to a test to ensure that the application navigation, functionality and Graphical User Interface (GUI) allows users to effectively and efficiently do their work in a way that they are satisfied with the application
• performance profiling: refers to a performance test that measures and evaluates response times and transaction rates
• load/stress/volume testing: refers to tests that measure and evaluate how a system performs and functions under varying workloads, large amounts of data and/or resource utilisation
• security and access control testing: focuses on the technical, administrative and physical security controls that have been designed into the system architecture in order to provide confidentiality, integrity and availability
• reliability testing: refers to the verification that failover methods are invoked properly and the system recovers properly
• configuration testing: refers to a test to ensure that the application or system can handle all hardware and software variables and requirements that have been defined
• installation testing: refers to the verification that the software installation process works properly in different environments and among varying conditions.

Examples of modelling technology include:

• Unified Modelling Langsuage (UML): a general-purpose notational language for specifying and visualising complex software, especially large, object-oriented projects
• Computer Aided Software Engineering (CASE) software: provides a development environment for programming teams. CASE systems offer tools to automate, manage and simplify the development process.

Examples of Database technologies include:

• Database 2 (DB2): a family of relational database products offered by IBM. DB2 provides an open database environment that runs on a wide variety of computing platforms
• Oracle: a relational database product; the first to support the SQL language
• SQL Server: a data management server product developed by Microsoft
• Sybase: a data management and synchronisation server products developed by Sybase.

Examples of Storage technologies include:

• network attached storage (NAS): a server that is dedicated to file sharing
• storage area network (SAN): a high-speed subnetwork of shared storage devices. A storage device is a machine that contains nothing but a disk or disks for storing data.

Examples of server/computer technologies include:

• enterprise server: a computer or device on a network that manages network resources and shared applications for multiple users
• mainframe: a very large computer capable of supporting hundreds, or even thousands, of users simultaneously. Mainframes support simultaneous programs.

Examples of embedded technology devices include:

• random access memory (RAM): a type of computer memory that can be accessed randomly; i.e. any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers
• hard disk drive: refers to the area of a computer where data is stored
• microprocessor: a silicon chip that contains a CPU. In the world of personal computers, the terms microprocessor and CPU are used interchangeably. At the heart of all personal computers and most workstations sits a microprocessor
• redundant array of independent disks (RAID): an assembly of disk drives that employ two or more drives in combination for fault tolerance and performance. RAID disk drives are used frequently on servers but are not generally necessary for personal computers. RAID is generally configured as mirrored or striped. Mirrored RAID (Level 1) provides a failover drive. Striped RAID (Levels 0, 3, and 5) write data across multiple disk drives so that a single disk failure can be recovered from the data on the remaining drives. There are three types of RAID systems: failure resistant disk systems (that protect against data loss due to disk failure): failure tolerant disk systems (that protect against loss of data access due to failure of any single component); and disaster tolerant disk systems (that consist of two or more independent zones, either of which provides access to stored data).

Examples of peripherals are:

• printer: a device that copies text or illustrations onto paper. There are many different types of printers.
• scanner: a device that can read text or illustration sprinted on paper and translate the information into a form the computer can use. A scanner works by digitising an image, dividing it into a grid of boxes and representing each box with either a zero or a one, depending on whether the box is filled in.
• facsimile (fax): the digitised image of text and/ or pictures, represented as a services of dots (bitmap). Faxes are sent and received through telecommunication channels such as the telephone or internet.
• graphics tablets: a pad-like device that uses a pen-like instrument to allow users to handdraw images that appear on a computer screen.
• cameras: a device that allows users to capture an image of their surroundings. The images may be still or moving and the images can be stored electronically or physically on film.
• assistive devices: These devices allow users to input information using a different medium than what is usually used. Assistive devices are often used to ensure greater accessibility for people with disabilities. An example of an assistive device would be speech recognition software, which converts audible human speech into words on a computer screen.

WANs include commercial or educational dialup networks such as CompuServe, Internet and BITNET.
Examples of WAN technologies include:

• frame relay: a packet-switching protocol for connecting devices on a WAN. Frame Relay networks in the U.S. support data transfer rates at T1 (1.544 Mbps) and T3 (45 Mbps) speeds
• asynchronous transfer mode (ATM): a high bandwidth, high speed, controlled delay, fixedsize packet-switching and transmission system integrating multiple data types (voice, video and data). It uses fixed-size packets also known as 'cells' (ATM is often referred to as 'cell relay').

Examples of LAN technologies include:

• Ethernet: LAN architecture that uses a bus or star topology and supports data transfer rates of 10 Mbps, 100 Mbps (fast Ethernet) or 1 Gbps (Gigabit Ethernet). The Ethernet specification served as the basis for the IEEE 802.3 standard, which specifies the physical and lower software layers.
• Token ring: a type of computer network in which all the computers are arranged (schematically) in a circle. A token, which is a special bit pattern, travels around the circle. To send a message, a computer catches the token, attaches a message to it and then lets it continue to travel around the network
• virtual LAN (VLAN): a network of computers that behave as if they are connected to the same wire even though they may actually be physically located on different segments of a LAN. VLANs are configured through software rather than hardware, which makes them extremely flexible. One of the biggest advantages of VLANs is that when a computer is physically moved to another location, it can stay on the same VLAN without any hardware reconfiguration.

Examples of network devices/standards include:

• hub: a common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets
• switch: in networks, a device that filters and forwards packets between LAN segments. Switches operate at the data link layer (layer 2) and sometimes the network layer (layer 3) of the OSI Reference Model, and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs
• router: a device or setup that finds the best route between any two networks, even if there are several networks to traverse. Like bridges, remote sites can be connected using routers over dedicated or switched lines to create WANs
• network Interface Card (NIC): an expansion board inserted into a computer so the computer can be connected to a network. Most NICs are designed for a particular type of network, protocol and media, although some can serve multiple networks
• transceivers: short for transmitter receiver, a device that both transmits and receives analogue or digital signals. The term is used most frequently to describe the component in local area networks (LANs) that actually allows signals onto the network wire and detects signals passing through the wire. For many LANs, the transceiver is built into the network interface card (NIC). Some types of networks, however, require an external transceiver
• gateways: points of entrance to and exit from a communications network. Viewed as a physical entity, a gateway is that node that translates between two otherwise incompatible networks or network segments
• integrated services digital network (ISDN): a system of digital phone connections which has been available for over a decade. This system allows data to be transmitted simultaneously across the world using end-to-end digital connectivity
• T1/T3: T1 service delivers 1.544 Mbps. It typically channels into 24 DS0s, each capable of carrying a single voice conversation or data stream. The European T1 or E1 transmission rate is 2.048 Mbps. A T3 circuit communicates at 45 Mbps, or 28 T1 lines
• digital subscriber line (DSL): refers collectively to all types of digital subscriber lines, the two main categories being ADSL and SDSL. Two other types of DSL technologies are High data rate DSL (HDSL) and Very high DSL (VDSL)
• firewall: refers to the network device that is designed to prevent unauthorised access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both. Firewalls are frequently used to prevent unauthorised Internet users from accessing private networks connected to the Internet, especially intranets. There are several types of firewall techniques and firewalls may implement one or more simultaneously. Packet filtering inspects inbound and outbound packets, validating against defined business rules. Application gateways apply security rules against applications. Circuit level gateways apply security rules against physical connection attempts to and from the network. Proxy servers mask the internal requestor by inspecting and augmenting the packet header. Four common architectures of firewalls include the packet filtering router, the screened host firewall system, the dual-homed host firewall and the screened subnet firewall (with a DMZ), which is one of the most secure implementations.

• bridge: a bridge connects three or more conference sites so that they can simultaneously pass data, voice or video. Video conferencing bridges are often called MCUs (multipoint conferencing units)
• codec: a video codec converts analogue video signals from a video camera to digital signals for transmission over digital circuits and then converts the digital signals back to analogue signals for display
• receiver: an electronic device which enables a particular videoconference signal to be separated from all others being received by an earth station and converts the signal format into a format for video, voice or data.