Message-oriented Middleware (MOM)

Message-oriented Middle ware is a middle ware framework that loosely connects differ-net applications through asynchronous exchange of messages. A MOM works over a networked environment without having to know what platform or processor the other application is resident on. The message can contain formatted data, requests for action, or unsolicited response. The MOM system provides a message queue between any two interoperating applications. lithe destination process is out of service or busy, the mes-sage is held in a temporary storage location until it can be processed. MOM is generally asynchronous, peer-to-peer, and works in publish/subscribe fashion. In publish/sub-scribe model one or many objects subscribe to an event. As the event occurs, it will be published by the asynchronous loosely coupled object The MOM will notify the sub-scribe rs about this event. However, most implementations of MOM support synchrony-nous (request/response) message passing as well MOM is most appropriate for event-driven applications. When an event occurs, the publisher application hands off to the messaging middle ware application the responsibility of notifying subscribers that the event has happened. In a net centric environment, MOM can work as the integration platform for different applications. Example of MOM are Message Queue from IBM known as Miseries. The equivalent from Java is,IMS (Java Message Service).

THREE-TIER ARCHITECTURE

THREE-TIER ARCHITECTURE To design a system for mobile computing, we need to keep in mind that the system will be used through any network, any bearer, any agent and any device. To have a univer-sal access, it is desirable that the server is connected to a ubiquitous network like the Internet. To have an access from any device, a web browser is desirable. The reason is simple; web browsers are ubiquitous, we get a browser in any computer. The browser agent can be Internet Explorer or Netscape Navigator or Mozila or any other standard Mobile Computing Architecture 39 agent. Also, the system should preferably be context aware. We will discuss context awareness later. We have introduced the concept of three-tier architecture. We have also discussed why it is necessary to go for Internet and three-tier architecture for mobile computing. The important question is what a mobile three-tier application actually should consist of. Figure 2.2 depicts a three-tier architecture for a mobile computing environment. These tiers are presentation tier, application tier and data tier. Depending upon the situation, these layers can be further sub layered.

Who makes the standards

There are many institutes that generate and provide standards across the world. There are standard bodies at the regional or country level; also, there are bodies at the inter-national level. Based on the area of operations, standard bodies are formed by the governments, professional institutes or industry consortiums. These standard bodies sometime also function as regulators. In India there is a standard body under the Government of India, which is called Bureau of Indian Standard or simply BIS (www.bis.org.in). A standards process include following steps: 1. Consensus on a proposed standard by a group or 'consensus body' that includes representatives from materially affected and interested parties. 2. Broad-based public review and comment on draft standards. 3. Consideration of and response to comments submitted by voting members of the relevant consensus body and by public review comm enters. 4. Incorporation of approved changes into a draft standard. 5. Right to appeal by any participant that believes that due process principles were not sufficiently respected during the standards development in accordance with the ANSI-accredited procedures of the standards developer.

LETF

The Internet Engineering Task Force (JEFF) is the standard-making body for Internet and related technologies. IETF is an open international community of network designers, operators, vendors and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet. It is open to any individual. The actual tedmical work of the IETF is done in its working groups. Working groups are organized into several areas by topic (e.g., routing, transport, security, etc.). The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique IP address. The IANA is chartered by the Internet Society (ISOC) to act as the clearinghouse to assign and coordinate the use of numerous Internet protocol parameters. Standards defined by IETF are called Request For Comment or RFC. The standard for email is defined in RFC821 (Simple Mail Transfer Protocol or SMTP); RFC2616 describes the version 1.1 of Hypertext Transfer Protocol.

STANDARD BODIES

The International Organization for Standardization (ISO) thttp://wwwiso.ch) is a worldwide federation of national standards bodies from more than 140 countries, one from each country. ISO is a nongovernmental organization established in 1947. The mission of ISO is to promote the development of standardization and related activities in the world with a view to facilitating the international exchange of goods and services, and to developing cooperation in the spheres of intellectual, scientific, technological and economic activity. Though ISO is commonly believed as the acronym for International Standard Organization, in fact the word 'ISO' is derived from the Greek isos, meaning 'equal'. Sometimes ISO makes its own standard, sometime it adapts standards from its member organizations and makes it an international standard. One of the most widely known standard from ISO is IS09000. IS09000 relates to Software quality. The famous 7-layer model for Open System Interconnection (OSI) is ISO standard (IS07498). For Information security ISO has come up with the recommendation ISO 17799. ziEb \var./ International Organization for Standardization

Making Legacy Application Mobile

How do we make a long life existing legacy application mobile? We define an applica-tion as legacy if it has one or more of the following characteristics: 1. The application has moved into the sustenance phase in the software develop-ment lifecycle. 2. An application, which cannot be modified. This could be due to unavailability of the original development platforms, unavailability of original source code or unavailability of expertise to make necessary changes. 3. Products and packaged software where enterprise does not have any control. This could be due to high cost of ownership for new upgrade or the vendor does not have any plan to support the new requirement. Let us assume that an enterprise has licensed an ERP system from an external vendor. The enterprise wants to offer a notification of yesterday's sales figures to some select executives at 9:30 AM everyday morning through SMS. The ERP vendor plans to offer similar function in their next release six months down the line. The license fee for the next upgrade will be very expensive. Another example is that a wireless network opera-tor wants to offer enterprise mails through its network. In all such cases the adaptation will be done without changing the base product. This requires a framework that attempts to perform most of the adaptation dynamically. Content and behavior management will be managed real-time through a behavior management middleware.

New Mobile Applications

Let us assume that in a bank, some new applications need to be built for e-Commerce. The bank wants to offer banking through voice (telephone) and Web (Internet). Assuming that the bank already has a computerized system in place, the bank will develop two new applications. One will handle the telephone interface through Interactive Voice Response (IVR) and the other through Web. At a later point in time, if the bank decides to offer SMS and WA_P, they will develop two new applications to support SMS and WAY interfaces respectively. To protect the invest-ment and quick adaptation, the bank may decide to use transaction processing middle-ware and RPC middleware. All these are possible only if it is a fresh applications development.