Page 417 - Handbook of Modern Telecommunications

3-208 CRC Handbook of Modern Telecommunications, Second Edition

These lists of principal functions should have a high level of matches with lawful intercept functions
as defined and recommended by the standards bodies of various continents.

3.8.5 Reference Models for Lawful Intercepts

3.8.6.1 CALEA Reference Model with the J-STD-025 Standard
CALEA definitions are related to the Telecommunications Act. The most important ones are extracted
as follows:
Telecommunications: the transmission, between or among points specified by the user, of information
of the user’s choosing, without change in the form or content of the information as sent and received.
Telecommunications service: the offering of the telecommunications for a fee directly to the public, or
to such classes of users as to be effectively available directly to the public, regardless of the facilities used.
Information services: the offering of a capability for generating, storing, transforming, retrieving,
utilizing, or making available information via telecommunications, and includes electronic publishing,
but does not include any use of any such capability for the management, control, or operation of a tele-
communications system or the management of a telecommunications service.
Telecommunication carrier (The term telecommunications service provider is preferred by the
authors in this handbook.): entity engaged in the transmission or switching of wire or electronic com-
munications as a common carrier for hire.
• includes commercial mobile radio service
• includes an entity engaged in the transmission or switching of wire or electronic communications
to the extent that the FCC finds that such service is a replacement for a substantial portion of the
local telephone exchange service and that is in the public interest to deem (it) to be a telecommu-
nications carrier for (these) purposes
• does not include entities insofar as they are engaged in providing information services
Call-identifying information: Dialing or signaling information that identifies the origin, direction,
destination or termination of each communication generated by means of any equipment, facility, ser-
vice or a telecommunications carrier.

3.8.6.1.1 CALEA Interfaces
The principal interfaces with the CALEA reference model are:
• Surveillance Administration System (SAS): Performs subject provisioning and receive alarms
related to CALEA interfaces
• Call Data Channel (CDC): A network connection reporting call-identifying information—CDC
messages—from the switch to the LEA
• Call Content Channel (CCC): A network connection delivering call content from the switch to
the LEA

The reference model is shown in Figure 3.8.4. It offers a generic view of the lawful intercept architec-
ture (access, delivery, and collection functions).

3.8.6.1.2 CALEA Principal Functions
There are basically three principal functions:
• Access Functions (AF)
• Network elements (CO switches, MSC, HLR, AAA, PDSN, SGSN, GGSN, routers, trunk-
ing gateways, soft switches, CMTS) that provide access to and replication of intercepted
traffic
• Sniffers and splitters that can passively monitor network traffic