Gateway

    IBM Cognos have below listed gateways-

• CGI-  It is default gateway. CGI can be used for all supported Web servers. To enhance performance or throughput, we may choose 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- We can use an apache_mod gateway with the Apache Web server.

• servlet- If Our Web server infrastructure supports servlets or we are using an application server, We can use a servlet gateway.

When an IBM Cognos BI gateway receives a request, it perform below tasks-

• It encrypts passwords to ensure security and did not allow unauthorized user to access.
• It extracts information needed to submit the request to an IBM Cognos BI server.
• It attaches environment variables for the Web server.
• It adds a default namespace to the request to ensure that the server authenticates the user in the correct namespace.
• It passes requests to an IBM Cognos BI dispatcher for processing.

Web Server

A Web server is an application designed to receive incoming browser requests and route them to the intended application (eg. Cognos). It is used to get all the information of user (authentication) via gateways.
      The IBM Cognos web server tier may have one or more IBM Cognos BI gateways. Web communication in IBM Cognos BI is typically through gateways. A gateway is an extension of a Web server, it transfers information from web server to application server.

Gateway-

 IBM Cognos BI supports several types of Web gateways.

• CGI
• ISAPI
• apache_mod
• servlet