COGNOS ARCHITECHTURE

THREE TIER ARCHITECHTURE



ARCHITECHTURE OF COGNOS
Cognos 8 has a multitiered architecture. For description purposes, it can be separated into three tiers: Web server, applications, and data. The tiers are based on business function, and are
typically separated by network firewalls. Below is the three tier architechure........
INTERFACES OF COGNOS
1) WEB BASED
2) WINDOW BASED

DIFFERENT TIERS OF COGNOS
Tier 1. W eb Server: Cognos 8 Gateways
The Cognos 8 Web server tier contains one or more Cognos 8 gateways.Web communication in Cognos 8 is typically through gateways, which reside on one or more Web
servers. A gateway is an extension of a Web server program that transfers information from the
Web server to another server.Web communication can also occur directly with a Cognos 8 dispatcher , although this option is less common than using gateways.If you install the gateway component on a different computer from Content Manager or Application Tier Components, you must configure the gateway computer so that it knows the location of a dispatcher, preferably one on an Application Tier Components computer. For failover protection, you can configure more than one dispatcher for a gateway computer .

DIFFERENT TYPES OF GATEWAYS:
• CGI:
The default gateway, CGI can be used for all supported Web servers. However, for enhanced
performance or throughput, you may choose one of the other supported gateway types.
• ISAPI
ISAPI can be used for the Microsoft Internet Information Services (IIS) Web server. It delivers
faster performance for IIS.
• apache_mod
You can use an apache_mod gateway with the Apache Web server.
• servlet
If your Web server infrastructure supports servlets or you are using an application server, you
can use a servlet gateway.

WORKING OF FIRST TIER
encrypts passwords to ensure security
• extracts information needed to submit the request to a Cognos 8 server
• attaches environment variables for the Web server
• adds a default namespace to the request to ensure that the server authenticates the user in the correct namespace
• passes requests to a Cognos 8 dispatcher for processing

TIER 2: APPLICATIONS--COGNOS 8 SERVERS
The Cognos 8 applications tier contains one or more Cognos 8 servers. A Cognos 8 server runs
requests, such as reports, analyses, and queries, that are forwarded by a gateway. A Cognos 8
server also renders the Cognos Connection and Metric Studio interfaces.
Each Cognos 8 installation includes
• Application Tier Components, which include a dispatcher , that operates services and
routes requests
• Content Manager , which manages Cognos 8 information
DISPATCHER
The dispatcher starts all Cognos 8 services configured and enabled on a computer, and routes
requests. The dispatcher is a multithreaded application that uses one or more threads per request.Configuration changes are routinely communicated to all running dispatchers. The dispatcher includes Cognos Application Firewall to provide security for Cognos 8.The dispatcher can route requests to a local service, such as the report service, presentation
service, job service, or monitoring service.A dispatcher can also route requests to a specific dispatcher to run a given request. Requests can be routed to specific dispatchers based on load-balancing needs, or package or user group requirements.
CONTENT MANAGER
Content Manager is the Cognos 8 service that manages the storage of customer application data,
including security, configuration data, models, metrics, report specifications, and report output.
Content Manager is needed to publish models, retrieve or store report specifications, manage
scheduling information, and manage the Cognos namespace

The information stored by Content Manager includes
• reports
Reports contain specifications, properties, security settings, and outputs. This includes
analyses created in Analysis Studio, queries created in Query Studio, and reports created in
Report Studio.
• report packages
Packages contain metadata, reports, and folders.
• metric packages
Metric packages contain metadata, scorecards, and folders.
• agents
Agents include the conditions, schedules, and tasks used to monitor events and deliver
notifications. This includes the list of recently detected instances of an event.
• server configuration
Server configuration contains directory information, the Cognos namespace (p. 98), and
information about contacts, distribution lists, data sources, and printers.
• personal user information
Personal user information consists of My Folders and My Pages.
• language information
Language information includes names, descriptions, and tool tips in different languages to
support Cognos 8 multilingual capabilities.
Content Manager performs general functions, such as add, query, update, delete ,
move, and copy.It also performs content store management functions, such as export and import.
TIER 3: DATA--CONTENT PROVIDERS
The Cognos 8 data tier contains the
• content store
• data sources
• metric store
CONTENT STORE
The content store is a relational database that contains data that Cognos 8 needs to operate, such
as report specifications, published models, and the packages that contain them; connection
information for data sources; information about the external namespace, and the Cognos
namespace itself; and information about scheduling and bursting reports. The relational database can be Cognos Content Database or a database from a supported third-party vendor.
DATA SOURCE
Data sources are relational databases, dimensional cubes, files, or other physical data stores that
can be accessed through Cognos 8. Application Tier Components use data source connections to
access data sources.
METRIC STORE
A metric store is a relational database that contains content for metric packages. A metric store
also contains Metric Studio settings, such as user preferences.More than one metric store may be created. For example, one metric store may contain content for a sales application and another metric store may contain content for a finance application.