Integrated Services The IETF Integrated Services Working Group is developing a set of standards that cover how application services define their requirements, how this information is made available to routers on a hop-by-hop basis, and ways of testing and validating that the contracted QoS is maintained. With the IntServ approach, each network element is required to identify the coordinated set of QoS control capabilities it provides in terms of the functions it performs, the information it requires, and the information it exports. IntServ capable routers must classify packets based on a number of fields and maintain state information for each individual flow. IP PBX IP Private Branch Exchange. A telephone, data and video switching system, usually located on customer premises and belonging to the user. Makes use of technologies like VoIP, Ethernet and standards like H.323. ISDN Integrated Services Digital Network, see also BRI and PRI. A switched digital service using a 16 Kbps "D" channel for signaling and two or more "B" 56 Kbps or 64 Kbps channels for signal data transmission.

The IETF's scheme to introduce QoS support over IP networks. It provides extensions to the best-effort service model to allow control over end-to-end packet delays. IntServ is a per-flow, resource reservation model, requiring RSVP. Its key building blocks include resource reservation and admission control.