An ITU-T H.248 media gateway (MG) provides operations on packet traffic in general, related to the ephemeral (and root) termination type. Several existing ITU-T H.248 packages include packet inspection as part of the overall defined service (such as gate management and packet filtering services according to [ITU-T H.248.43]).

This Recommendation defines additional ITU-T H.248 capabilities for so-called deep packet inspection (DPI) related services. Understanding and definition of DPI in this Recommendation follows principally [ITU-T Y.2770]. The "DPI concept" is fundamentally coupled with the architecture of layered protocol stacks, as expressed by the acronym words 'deep' and 'packet'. Figure 1 depicts DPI in an example of an ITU-T X.200 layered protocol architecture, and also illustrates the historical evolution from shallow packet inspection (SPI) over medium depth packet inspection (MPI) towards DPI. It should be noted that SPI and MPI are colloquial terms, whereas clause 3.2.5 of [ITU-T Y.2770] defines DPI. Further, the notion of 'packet' is used in the broadest sense, typically nowadays focusing on IP packets [IETF RFC 791], [b-IETF RFC 2460], but covering non-IP traffic as well.

This Recommendation:

- clarifies the understanding of DPI versus non-DPI in context of the ITU-T H.248.x-series of Recommendation (clause 5.2);

- describes the relation of "policy rule" support by existing ITU-T H.248 packages (clause 6); and

- defines new ITU-T H.248 packages for flexible DPI support in various network scenarios (clauses 7 to 9).