Practical VoIP Using VOCAL

Authentication

The authentication provided by the Marshal depends on the Marshal type. User Agent Marshals perform user-level authentication . PSTN Gateway, Conference, and Internetwork Marshals perform gateway-level authentication.

What Is Authentication?

Authentication is the process that protects the system from unauthorized users. The Marshal servers authenticate each call by checking the calling party’s IP address against a master file. If the Marshal does not have the calling party’s address on its list, it requests verification from the Provisioning server. If the Provisioning server does not verify the address, the Marshal refuses to authenticate the call. The authentication method can be either access list or digest.

That takes care of the high-level picture. The lower-level picture has to do with the actual security of a single call.

User-Level Authentication

All User Agent Marshals perform user-level authentication. Each user within a given VOCAL system is configured with its own authentication scheme and Marshal group.

The authentication scheme is one of the following:

Marshal group

The Marshal group is the group of one or more Marshals through which the user communicates with the VOCAL system. When a User Agent Marshal receives an incoming SIP request, it reads the user portion of the From header to determine the user. Then it gets, and caches, the user’s information from the Provisioning server to determine which type of authentication to enforce.

None

If a user is ...