This Recommendation provides a framework for deep packet inspection (DPI) in packet-based networks. The primary purpose of this Recommendation is to describe the fundamental concepts, functional components and capabilities of DPI that can be used to identify information flows in packet-based networks by DPI entities, to support the specification of DPI requirements and to guide structured solutions for packet-based networks (such as NGNs).

This Recommendation provides high-level system information with regard to some fundamental concepts as typically relevant when realizing DPI entities. However, it is not expected to present all-inclusive detailed specifications for the DPI. Rather, this Recommendation provides an highlevel information (i.e., a framework) and is intended to be used as background material for use by ITU Study Groups and other expert groups outside the ITU, e.g., as input for their development of detailed standards for DPI functionalities.

The scope of this Recommendation includes:

a) basic architectural principles that will be encountered in combining DPI in various network architectures;

b) protocol architectural aspects from the perspective of DPI;

c) example functional models and their application to DPI use case scenarios; and

d) performance frameworks in order to assist in DPI performance discussions like the identification of key performance indicators related to DPI.

Implementers and users of this ITU-T Recommendation shall comply with all applicable national and regional laws, regulations and policies. The mechanism described in this Recommendation may not be applicable to international correspondence in order to ensure the secrecy and sovereign national legal requirements placed upon telecommunications providers, as well as the ITU Constitution and Convention.