Tier 1. Web Server: IBM Cognos 8 Gateways 

The IBM Cognos 8 Web server tier contains one or more IBM Cognos 8 gateways.

Web communication in IBM 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 an IBM 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 .

IBM Cognos 8 supports several types of Web gateways, including

• 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.

When an IBM Cognos 8 gateway receives a request, it

• encrypts passwords to ensure security

• extracts information needed to submit the request to an IBM 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 an IBM Cognos 8 dispatcher for processing

For information about configuring IBM Cognos 8 gateways, see the Installation and Configuration Guide.