The PDF for this CALEA solution called DHCPatriot seems informative.
"Any type of broadband that supports DHCP can benefit from the DHCPatriot™. Easy access to both session data and IP address utilization information is standard. Add a NetEnforcer® from Allot Communications into the network and utilize the integration between these two products for a powerful combination tat will enable flexible handling of virtually any situation in any network."
"Law enforcement is interested in two categories of information during a lawful interception of a target: “Call Data” and “Call Content.” Call Data is identifying information (example: target login and logout times) that can be used to identify a target on the Internet as well as the target's communications, known as Call Content. Almost all warrants will require Call Data. Some will require Call Content as well."
The interception is achieved via three types of network elements performing three functions: Access, Mediation and Collection. The Access Function refers to the network elements responsible for the interception and transfer of the Call Data and Call Cotent to the Mediation Function. The Mediation Function is responsible for the formatting of the intercepted information and its delivery to the LEA (Law Enforcement Agency). The Collection Function is performed by a network element in the LEA's network for storage, formatting and review.
CALEA requires that two facets of privacy be protected. The LEA can only be allowed to access information that is covered by warrant, and no other information regarding the Target, or any other customer on the service provider's network. Secondly, if multiple LEAs are engaged in surveillance of a particular target, they can not be aware of each other. The purpose of the Mediation Function is to insure that these two requirements are met.
CALEA also requires that the target must not be able to detect the surveillance activities of the LEA. Therefore, no changes to a target's access may be made in order to facilitate a lawful interception. Changing a target to a static IP address when they usually get their IP address via DHCP or changing the path their traffic tkes to facilitate an interception allow possible detection by the target, and therefore cannot be used under CALEA.
CALEA does allow a service provider to utilize a “Trusted Third Party” vendor, a contracted company to provide mediation device services for the Mediation Function between law enforcement and the service povider. Placing this portion of the solution in the hands of a Trusted Third Party vendor is often the most viable solution. This also greatly reduces the effort involved in implementing the solution.
Many service providers will be reluctant to invest the resources needed to a platform used strictly for CALEA compliance such a the Mediation Function and will take full advantage of this scenario. Others will choose to purchase their own mediation device. The DHCPatriot™ can help in either case.
Read the rest in the PDF.