Netscape Application Server Application Server for Business-Critical Applications Presented By : Khalid Ahmed DS Fall 98

OLD CLIENT-SERVER MODEL  Connection Clients were required to have dedicated lines, leased lines, dialups, or some other access to the Server. u Network Protocol Clients had to use the same network protocols as the Server they wanted to communicate with, TCP/IP, IPX/SPX, NetBUI, etc. u Hardware Requirements Clients had to meet specific machine requirements: microprocessor speed; screen resolution; RAM; hard disk space; modem speed; etc. Clients were required to make a huge investment in hardware.

OLD CLIENT-SERVER MODEL u Operating System Requirements The Clients had to run a specific Operating System and version. u Software Updates Application updates via floppy disks or CDs were frequent. The Client was required to perform the costly installation or update.

New Client-Server Model  Internet Connection Clients need only have access to the Internet to access a website. Network requirements are largely eliminated because TCP/IP is the default Internet protocol. Now it’s easy for clients to communicate with a server.  Instant Access Clients no longer need to install or update applications, they simply access the service on a website. Any updates you’ve made to the application will be immediately available. Now it’s easy and inexpensive for you to update your services. u Client Browser Clients can use almost any browser and they don’t need special hardware. They can also use any Operating System and version for which a web browser exists. Now it’s inexpensive for clients to access a server.

DB Databases Documents Enterprise Data Web Server CGI, SSJS, NSAPI, ISAPI, WAI, Etc. Client Browser Internet Connection Basic Web Applications

Robust Web Applications Presentation Tier Rich Clients (Java C/C++, VB ) Web Browser Business Logic Tier Web Servers Application Servers Data Tier Databases Enterprise C/S Applications Legacy Systems Documents HTTP IIOP

Requirements of Web-based Business Applications u Transaction Management Capabilities u Scalability u High Performance u Robustness u Security In order to deploy robust applications over the web, the web solution must deliver on the following key requirements for business critical computing:

Shortcomings of the Web for Deploying Business Applications u Lack of transaction management capabilities and stateless environment. u No model for application scalability. u Unpredictable performance under heavy and varying loads. u Difficult application deployment and management. u Lack of end-to-end security.

Netscape Application Server ( NAS ) u Rapid deployment of transactional applications. u Session and state management. u High scalability. u High performance. u Security. u Dynamic content generation. u Management capabilities. Netscape application server is a programmable application server. It provides all the core system and application services required to enable rapid deployment and facilitate management of high volume, transaction-based web applications. Some of it’s key features include:

Key Components of Netscape Application Server

Netscape Application Server Architecture

Netscape Application Server Components u Web Server to Netscape Application Server (NAS) Communication Communication between a web server and NAS occurs through NSAPI, ISAPI and optimized CGI. Communication with the web browsers occurs through the HTTP, SHTTP or SSL protocols. u Load Balancing System Incoming requests first pass through the NAS load balancing system, which directs requests to available servers for optimized processing under heavy loads. u Request Management System The NAS is a multi-threaded system and the Request Management System assigns threads from a dynamic thread pool to process the requests.

Netscape Application Server Components u Application Logic Processing System The application logic processing system handles all requests related to processing business logic. Requests are identified by their Globally Unique IDentifier (GUID) and checked against the Global Directory Service (GDS). The GDS determines the language of the application logic object. It then loads the appropriate language specific handler for the request.It could be a.class file for a java application or a.DLL file for a C++ application. u System and Application Services These services can be broadly classified into four categories:

Netscape Application Server Components u Administrative Services The administrative services provides us with a framework for managing distributed NAS and applications. It supports Java based administrator tools for easy point-and-click management of servers and applications.  Kernel Services It provides low-level services to all the other services and sub-systems. l Transaction Management System l Database Access Services l Presentation Services l Application Services

How does the NAS operate ? When a request comes in from a web browser, the request is passed to the web server via the HTTP, SHTTP or SSL protocol. The request is processed by the appropriate Web Connector such as NSAPI (for Netscape webservers) or ISAPI (for Microsoft web servers). The request is then forwarded to a correspondong Listener. The web connectors and listeners manage the passing of requests from the web server to the NAS. In a environment with multiple NAS, a request is first handled by the Load Balancing System. It then directs the request to the server best suited for this process. The Request management system

How does the NAS operate ? then assigns threads from a dynamic thread pool to process the request. The request is then handed to the application logic processing system where the appropriate application logic is executed to process the request. Application logic processing might involve calling one or more functions from the following subsystems:  Data Access Services such as database access operations and connection caching.  Transaction management system such as transaction manager and database request manager.  System and Application Services such as session manager and distributed state manager.  Presentation Services such as presenting formatted data to the browser.

NAS Applications as part of a three-tiered environment. The applications on a Netscape Application Server run in a distributed, three-tiered environment.

NAS Applications as part of a three-tiered environment. Client Tier The first tier is the client or user interface tier. The software providing the user interface can be either a web browser displaying a HTML page or a client application installed on desktop PC’s. Middle Tier The middle tier is the NAS. This tire consists of server machines running both NAS software and server-side application code. Database Tier The database tier consists of one or more database servers, which can be from different vendors.

Netscape Application Builder Rapid Development of Business Applications Wizards for Point-&-click Development Pre-built Application Services and Class Libraries (Java, C/C++) Reusable Application Components Distributed Deployment of Application Components Distributed Development Using Three-Tier Programming Model

Netscape Application Builder Robust Application Development Tools Application Logic Designer HTML Designer Query Designer Project Manager Third-party Tool Support

Netscape Server administration Advanced cluster management Enterprise-wide views of all servers and processes Event monitoring & alerts Multi-view graphical performance monitoring ACL, User & Group Management Load balancing customization Application administration Application partitioning Integrated deployment

Summary Key Benefits of the Netscape Application Server: n Enables Rapid Development of Business Applications n Provides Industry Leading Performance & Scalability n Provides High Availability & Reliability n Enables Enterprise Application Integration Allows Client-Independence (HTML, Java, C++, VB) n Provides Open & Extensible Architecture