Transcript NETSCAPE APPLICATION SERVER

Netscape Application Server
Application Server for Business-Critical Applications
Presented By : Khalid Ahmed
DS 520 - Fall 98
OLD CLIENT-SERVER MODEL
Connection
Clients were required to have dedicated lines, leased lines, dialups,
or some other access to the Server.
Network Protocol
Clients had to use the same network protocols as the Server they
wanted to communicate with, TCP/IP, IPX/SPX, NetBUI, etc.
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
Operating System Requirements
The Clients had to run a specific Operating System and version.
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.
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.
Basic Web Applications
Documents
Internet Connection
Client
Browser
DB
Databases
Web
Server
CGI, SSJS, NSAPI,
ISAPI, WAI, Etc.
Enterprise
Data
Robust Web Applications
Business Logic
Tier
Presentation
Tier
Data Tier
HTTP
Documents
Databases
Web
Browser
Web
Servers
Enterprise C/S
Applications
Application
Servers
Rich Clients
(Java C/C++, VB)
Legacy
Systems
Requirements of Web-based Business
Applications
In order to deploy robust applications over the web, the web
solution must deliver on the following key requirements for
business critical computing:
 Transaction Management Capabilities
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Scalability
High Performance
Robustness
Security
Shortcomings of the Web for Deploying
Business Applications
 Lack of transaction management capabilities and
stateless environment.
 No model for application scalability.
 Unpredictable performance under heavy and varying
loads.
 Difficult application deployment and management.
 Lack of end-to-end security.
Netscape Application Server (NAS)
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:
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Rapid deployment of transactional applications.
Session and state management.
High scalability.
High performance.
Security.
Dynamic content generation.
Management capabilities.
Key Components of Netscape Application
Server
Netscape Application Server Architecture
Netscape Application Server Components
 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.
 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.
 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
 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.
 System and Application Services
These services can be broadly classified into four
categories:
Netscape Application Server Components
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Transaction Management System
Database Access Services
Presentation Services
Application Services
 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.
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
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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
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Application Logic
Designer
HTML Designer
Query Designer
Project Manager
Third-party Tool
Support
Development Tools
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
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Summary
Key Benefits of the Netscape Application Server:
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Enables Rapid Development of Business Applications
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Provides Industry Leading Performance & Scalability
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Provides High Availability & Reliability
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Enables Enterprise Application Integration
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Allows Client-Independence (HTML, Java, C++, VB)
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Provides Open & Extensible Architecture