An Introduction to the BEA WebLogic Communications Platform

by Ken Lee
02/10/2006

Abstract

The telecom network industry is facing increasing pressure to drive up revenue, keep costs down, launch new services, and invest in evolving legacy networks to an IP-based, next-generation network. The BEA WebLogic Communications Platform product family is the industry's first product suite to deliver a converged service creation and execution platform combined with a powerful policy enforcement platform, to enable telecom network operators to reach their new revenue potentials faster and more cost effectively. This article provides a high-level overview of the products and technologies that form the basis for the WebLogic Communications Platform.

Converging IT and Telecom Services

The BEA WebLogic Communications Platform is a product suite consisting of two products: BEA WebLogic SIP Server and BEA WebLogic Network Gatekeeper. BEA WebLogic SIP Server is an integrated Java Enterprise Edition (Java EE) and Session Initiation Protocol (SIP) application server, based on the Java community standard SIP Servlet APIs (JSR 116). Specifically, WebLogic SIP Server has implemented a SIP servlet container that has been integrated with an HTTP servlet container, such that the HTTP and SIP application components are co-located on a single Java EE platform. WebLogic Network Gatekeeper is a policy-based, service-level agreement (SLA) enforcement and Telecom Web Services platform that can be plugged into a carrier's network infrastructure using a modular resource adapter framework. Both products are designed to allow developers unfamiliar with telecom network protocols to communications-enable existing IT and Web-based applications using existing IT application development APIs and tools. This facilitates the introduction of IT-based applications, services, and platforms into the telecom service infrastructure layer.

The two products within the WebLogic Communications Platform are complementary. WebLogic SIP Server is a platform for enterprises and telecom network operators to create and proliferate new communication services. As operators increase the number of applications coming into their networks from third-party content and application providers, WebLogic Network Gatekeeper can be used by network operators to control access and usage of their networks by third-party partners and their own applications.

Making It Easier for Developers

For developers, WebLogic Communications Platform products provide a Java and Telecom Web Services path to building communication-enabled applications. Through BEA WebLogic SIP Server, developers already familiar with the HTTP Servlet programming model can easily create SIP-based applications using the SIP Servlet APIs, which are SIP extensions to the Java EE HTTP Servlet APIs and container. Because WebLogic SIP Server implements an integrated HTTP-SIP servlet container, developers can deploy the HTTP servlet and SIP servlet on a single Java EE platform, instead of on two separate platforms. This facilitates a faster and more efficient application development and deployment lifecycle.

Another avenue for building converged IT-telecom services is through Telecom Web Services. In this model, developers can create applications using their choice of programming language and component models, and communication-enable their applications via Telecom Web Services. WebLogic Network Gatekeeper implements Telecom Web Services APIs, based on the industry-standard called Parlay X Web Services APIs, as defined jointly by The Parlay Group, ETSI (European Telecommunications Standards Institute), 3GPP (Third Generation Partnership Project), and 3GPP2. This allows developers who are unfamiliar with telecom network element protocols, such as SMPP for SMS, MM7 for MM7, LIF/MLF for Location, and others, to create applications that can send SMS and MMS, and request and receive user location information by consuming WSDL over SOAP. This makes it possible for network operators to open up their high-value telecom network capabilities to third-party developers and service providers, while using the automated authentication and authorization network access control mechanisms built into WebLogic Network Gatekeeper. Figure 1 provides an overview of the products and their place within the platform.

Figure 1
Figure 1. BEA WebLogic Communications Platform overview

By leveraging the Java and Telecom Web Services APIs on which WebLogic Communications Platform products are implemented, telecom network operators now have access to a wider community of application developers beyond their traditional telecom application developer base. These are developers who traditionally build applications for the Web community, as well as for enterprise IT. Due to the gradual breaking down of barriers between Internet services and telecom services, it's to the benefit of network operators to tap into the proven innovations of the Internet to make communication services richer and more useful.

SIP Servlets

The SIP Servlet API, standardized as JSR 116 within the JCP (Java Community Process), provides the Java application programming model for developing SIP applications. The SIP Servlet API version 1.0 was published in February 2003, and the next revision, SIP Servlets v1.1, is currently being defined as JSR 289. Java EE specifies the HTTP Servlet, which is a main technology for building Web-tier applications. SIP Servlet is defined as the generic servlet API with SIP-specific functions added. SIP servlets are very similar to HTTP servlets, and HTTP servlet developers will quickly adapt to the programming model. SIP Servlet and HTTP Servlet have many things in common:

  • Servlets must inherit the base class provided by the API. HTTP servlets must inherit HttpServlet, and SIP servlets must inherit from SipServlet.
  • Methods doXxx() must be overridden and implemented. HTTP servlets have doGet()/ doPost() methods corresponding to GET/POST methods. Similarly, SIP servlets have methods corresponding to appropriate SIP actions, such as doAck() and doSubscribe(). Application developers override and implement appropriate methods.
  • The lifecycle and management method init() and destroy() of SIP Servlet are exactly the same as HTTP Servlet. Manipulation of sessions and attributes is similar.
  • The SIP Servlet world has a deployment descriptor called sip.xml, which corresponds to web.xml for HTTP servlets. Application developers and service managers can edit this file to configure applications using multiple SIP servlets.

There are, however, several differences between SIP and HTTP servlets, many deriving from the difference in underlying protocol. For a more technical introduction to SIP servlets, read An Introduction to SIP (dev2dev, February 2006).

WebLogic SIP Server

WebLogic SIP Server is the SIP application server component of the WebLogic Communications Platform product family. It provides an integrated Java EE and SIP Servlet-based application container for hosting and executing SIP-based application logic. WebLogic SIP Server delivers a unique implementation of the JSR 116 SIP Servlet APIs and containers, by integrating it with the Web-tier Servlet container of WebLogic Server, with both containers running on the WebLogic Server platform.

JSR 116 SIP Servlet APIs are the Java community standard for creating and deploying SIP-based applications. In WebLogic SIP Server, the SIP Servlet programming model is integrated with the Java standard for creating and deploying HTTP-based applications. As a result, applications created for WebLogic SIP Server can be deployed into either the SIP Servlet or HTTP Servlet container, with the ability for events and requests to be invoked from one container to the other, creating a truly converged HTTP-SIP application. Because the two containers are integrated, the operation, administration, and management attributes are all shared, as well as security, performance, and availability.

Figure 2
Figure 2. BEA WebLogic SIP Server product architecture

A key benefit for developers of having a converged HTTP-SIP servlet container (see Figure 2) is that HTTP applications can now trigger events in SIP applications, and vice versa, without going outside the servlet container. For example, most use cases of SIP applications involve an HTTP-based interaction—whether they are consumer or enterprise end users, a request for information or a service may begin via a HTTP-based interaction via a Web-based client application. From there, the end user may decide to engage in a commercial transaction, or if a SIP-enabled service is available, choose to click-to-service, where the service can be a call, an instant message, or any other type of communication or collaboration activity. Before the users decide on a course of action, they may be able to leverage the presence, location, and contact preference information made available. In the end, users who began with a HTTP transaction will end up initiating a SIP request after which they may return to HTTP-based activities.

WebLogic Network Gatekeeper

WebLogic Network Gatekeeper is the policy enforcement and Telecom Web Services component of the WebLogic Communications Platform product family. This product abstracts out the application interface and the network interface within the services layer in a network operator's service delivery platform. The application interface is commonly referred to as the "northbound" interface, and exposes telecom network service capabilities such as messaging, call control, location, and presence services to developers through high-level Web services. This allows developers who are not well-versed in telecom protocols and APIs to create new communication services using WSDL and SOAP. In WebLogic Network Gatekeeper, these northbound application interfaces are referred to as Telecom Web Services.

By exposing both traditional (legacy) telecom service APIs and new, high-level Web services, operators and application developers can select the most appropriate APIs for each application. The selection can be based on performance requirements, application complexity, or developer skills, for example. In addition, current applications using SMPP and CIMD, for example, can be integrated with WebLogic Network Gatekeeper "as is" and thereby leverage current application investments—that is, they can take advantage of the policy, charging, and SLA enforcement mechanism offered by WebLogic Network Gatekeeper.

The network interface is commonly referred to as the "southbound" interface and allows WebLogic Network Gatekeeper to be integrated with various carrier-specific telecom network capabilities, using a modular plug-in architecture. Examples of southbound plug-ins include adapters for sending and receiving requests using SMPP for SMS, MM7 for MMS, and LIF/MLF for Location. By providing a large set of standard network protocols, operators can quickly provide applications with access to GSM, GPRS, SIP, IN, and 3G service nodes directly through IP-based service nodes (SMSC, MMSC, and so on) or through OSA/Parlay gateways.

WebLogic Network Gatekeeper northbound and southbound interfaces can be extended to accommodate network operator-specific requirements for additional Telecom Web Services, as well as network interface adapters, using the Extension SDK for WebLogic Network Gatekeeper. The SDK also provides an application developer tool, which includes a network simulation tool for developers to test out new applications they have developed to the Telecom Web Services interfaces. Using a modular architecture where both the application and network interfaces are extensible makes it easy for operators to create attractive service offerings based on their unique network service capabilities—new application and network interfaces are easily added when new or enhanced service capabilities are introduced in the networks.

The core of WebLogic Network Gatekeeper is its powerful policy enforcement engine. With its policy-based application access control operators can dynamically customize both the SLA data and the actual access rules to fit their business models and security requirements. Using policy and subscriber profile data, WebLogic Network Gatekeeper can perform a number of subscriber-related checks before a service request is accepted. For example, WebLogic Network Gatekeeper can control which services the subscriber has subscribed to, the payment method to use, the account status, subscriber-specific white and blacklists, and if aliasing shall be used. These checks are applied on both application- and network-initiated requests.

Summary

This article focused on the core technologies, standards, and component products that comprise the WebLogic Communications Platform product family, paying specific attention to those areas most relevant to developers interested in creating converged IT and communication applications. WebLogic SIP Server delivers a very high-performance, converged HTTP Servlet-SIP Servlet application container, designed to provide developers with a powerful service creation, deployment, and execution environment for real-time, interactive, multimedia applications over SIP. With WebLogic Network Gatekeeper, developers are able to communication-enable existing as well as new applications using high-level and simple Telecom Web Services interfaces, based on the Parlay X Web Services standard.

References

Ken Lee manages product marketing for the WebLogic Communications Platform product family, which includes the WebLogic SIP Server and WebLogic Network Gatekeeper.