TMCnet - World's Largest Communications and Technology Community



tmc logo
November 2007 | Volume 10/ Number 11
Feature Articles

Can your IP PBX Provide Internet-like Flexibility without Sacrificing Carrier-Grade Attributes?

By Indu Kodukula and Tom Randulff

As IP has become widespread and Session Initiation Protocol (SIP) has emerged as a protocol of choice for telephony signaling, enterprise PBX systems are transforming. The hosted IP PBX has emerged as a communication solution in the enterprise that takes advantage of the movement from circuit switched networks to IP. The movement to IP has also made it easier for a carrier to host the PBX system without sacrificing enterprise security or performance. This hosted aspect of next-generation PBX solutions is particularly relevant to small and medium-sized enterprises and even branch offices of large enterprises, which are increasingly reluctant to have dedicated, on-site staff that specialize in complex, proprietary PBX solutions.

What has made this change possible? When we look at the underlying factors of this industry transformation, three trends emerge. First, the ubiquity of IP, the standardization of SIP as a control protocol, and the availability of inexpensive SIP hard phones and (virtually) free SIP soft phones have made PBX features more accessible than ever before. Gone are the days when the phone that offered PBX features was completely vendor-specific, was guaranteed to work with a feature server only from that vendor, and required finger calisthenics to make use of simple PBX features such as call forwarding or hunt groups.

The second trend driving this industry transformation is the maturity of Internet platforms in general and Java Platform Enterprise Edition (Java EE) specifically as an execution environment for telephony services. Whereas previous generation feature servers were proprietary, vertically integrated black boxes, vendors are building next-generation feature servers - which run on commodity hardware - as applications on a highly programmable and flexible Internet platform. The combination of cheaper hardware, flexible platforms, and an Internet-style programming model is making IP PBX solutions more usable and flexible than ever before.

Finally, as communication costs have fallen and devices have proliferated, it is particularly important that an information worker have access to PBX features from any device, from any location, and at any time. Whether employees are communicating from home through a VoIP client over a broadband connection, from their desks through a SIP hard phone, or from their mobile phones, they need access to the same set of employee-specific PBX features. With traditional PBX systems, this is next to impossible to achieve. However, a hosted IP PBX solution is tailor-made for this scenario.

This article will explore how IP PBX solutions built on standards-based Internet platforms such as Java EE can be supremely flexible, addressing highly variable user requirements without sacrificing the reliability, availability, and scalability (RAS) characteristics traditionally expected of such solutions.

Have Your Cake, Eat it Too, and Lose Weight in the Process

When choosing an IP-PBX, an obvious question an enterprise should ask is why it should select a product that is built on a Java EE platform. The answer is simple - there are more than three million Java developers out there building Internet applications. The unprecedented speed of innovation in the Internet, including the rapid rise of phenomena such as Web 2.0, has been made possible by the talented developer pool that is familiar with Java and uses Java and Java EE to build many innovative applications. At the same time, Java has a well-defined process for incorporating innovation and is one of the two de facto standards for developing Internet applications (the other being the Microsoft way). Getting even a fraction of this developer pool interested in developing applications such as IP PBX can result in increased feature innovation, lower cost, and enhanced integration with other enterprise business processes.

The telecommunications industry has long viewed Java with suspicion because features such as dynamic memory allocation and de-allocation (“garbage collection”) have made it difficult to build applications with predictable, millisecond response times on the platform. Fortunately, the maturity of these “garbage collection” techniques, the availability of high-performance in-memory databases such as Oracle TimesTen, and clever memory utilization techniques have all allowed Java to overcome this barrier successfully. In addition, Java has always been a platform for scale and throughput - witness that some of the most active websites, such as eBay, are built on Java or Java EE.

Early attempts to integrate communications protocols such as SIP into Java resulted in relatively clumsy attempts in which application developers still had to worry about details of the underlying protocols. However, Java has evolved rapidly to incorporate the needs of communications-centric applications. Just as the HTTP Servlet programming model was developed to make simple Web application development easier without requiring developers to have a detailed knowledge of the HTTP protocol, similarly, the SIP Servlet specification was initially proposed in the Java Community Process (JSR 116) and is being significantly revamped (JSR 289). The benefit of the SIP Servlet model is that there is now a simple, familiar programming model that a traditional Java EE/Web developer can use to begin developing communication-centric applications.

As enterprises and vendors have already integrated Java into enterprise computing, the adoption of Java for building next-generation communication systems simplifies the task of integrating enterprise computing and communications. To start, developers can easily expose network capabilities through either Java or Web Service APIs, which can then be easily integrated into enterprise computing. A simple example is the integration of “click-to-dial” capability in a helpdesk application. If the ability to initiate a phone call to an available helpdesk representative can be exposed as a Web Service, it is simple to integrate that capability into a web-based helpdesk application. Such exposure also makes it possible to bring the SOA notions of reusability, managed exposure, policy enforcement, and orchestration to the communications domain.

A more PBX-specific example is the web-based attendant functionality that can be found on a Java EE-based IP PBX solution such as the Oracle Virtual PBX. Normally, an attendant client in a PBX is a rich, windows-based application that is specific to a named user. The human operator is required to be present at the console to function as an attendant. In addition, connectivity to a hosted feature server typically requires opening up firewall ports, resulting in increased security risk. In contrast, an attendant that is a component of a Java EE-based IP PBX solution can be delivered simply over the web as a Java web start application and downloaded by a human operator regardless of his/her location, using standard Internet protocols. Enterprises can use standard Java EE/web security models for authentication, authorization, and entitlements to ensure that human operators cannot compromise corporate data even though the operators might be external to the company firewall. At the same time, the web-based delivery of the attendant functionality significantly simplifies the process of attendant administration and upgrade. The Web user interface is familiar to everyone and minimizes the training needs for traditional proprietary client interfaces associated with attendants. Enterprises can easily customize the look and feel of such an attendant using standard web technology such as cascading style sheets (CSS).

By building an IP PBX solution on a Java EE platform, it is also possible to leverage the full power of Java EE as a programming platform for building Web applications. In particular, it is possible to integrate the PBX solution with enterprise information stores - such as Lightweight Directory Access Protocol (LDAP) - and implement simple, corporate-wide policies for PBX communications. It is also straightforward to integrate the IP PBX solution with an enterprise self-service portal where users can easily customize their PBX experience (e.g., define speed dial numbers). Such ease of use and administration can dramatically improve the usability of advanced PBX features such as hunting groups, virtual private numbers, and sophisticated call filtering.

A specific example of such a PBX solution built on a Java EE platform is the Oracle Virtual PBX, a component of the Oracle Service Delivery Platform (Oracle SDP) - a Java EE-based carrier-grade service creation and execution environment. As part of the Oracle Service Delivery Platform, the Oracle Virtual PBX exhibits the benefits outlined above, combining carrier-grade deployment characteristics with a highly customizable look-and-feel and feature set.

Java and Java EE continue to evolve rapidly to address the challenge of communications and computing convergence, and the resulting benefits to enterprises and the industry at large are numerous: more innovative use of computing capabilities in enterprise applications, faster integration and time-to-market of these new services, and managed exposure of communication capabilities through SOA principles. The availability of programming models such as SIP Servlets and APIs such as Parlay and Parlay X is accelerating the realization of these benefits.


In conclusion, the standardization of networking interfaces, the arrival of SIP as a standard control protocol, and the maturation of Internet Java EE platforms provide a tremendous opportunity for enterprises that are looking to integrate enterprise communications seamlessly into enterprise business processes. IP PBX solutions that are built on a Java EE platform are flexible and customizable at will; at the same time, Java EE provides the carrier-grade foundation that enables such an IP PBX system to perform with the reliability, scale, and availability traditionally required of communications systems. IT

Indu Kodukula is Vice President, Product Management for the Oracle Service Delivery Platform (SDP). Tom Randulff is Senior Product Manager for Oracle. For more information, visit the company online at

» Internet Telephony Magazine Table of Contents

Today @ TMC
Upcoming Events
ITEXPO West 2012
October 2- 5, 2012
The Austin Convention Center
Austin, Texas
The World's Premier Managed Services and Cloud Computing Event
Click for Dates and Locations
Mobility Tech Conference & Expo
October 3- 5, 2012
The Austin Convention Center
Austin, Texas
Cloud Communications Summit
October 3- 5, 2012
The Austin Convention Center
Austin, Texas