ATIS - Alliance for Telecommunications Industry Solutions
Scope
Scope@ Purpose and Application This document specifies classes of Quality of Service (QOS) sufficient to support Business Multimedia Conferencing on Internet Protocol (IP) networks@ defined as equivalent to legacy conference system performance (e.g.@ H.320 at Basic Rate Interface (BRI) rates). It also specifies the threshold of perceptible impairment for some user interface parameters. This standard applies to communications between a subset of multimedia end-points@ namely Video Teleconference room systems and Desktop systems. The current scope is limited to H.323 point-to-point communication (Multipoint communication is for further study). It applies to cases where IP is utilized between the end-points (e.g.@ IP/Circuit-Switched Hybrid Network connections are for further study@ e.g. networks supporting H.320-compliant terminals). A user-to-user connection has components on the Customer Installation@ and components of one or more network service providers between the network interfaces. The Customer Installation includes a multimedia communication system (Terminal Equipment@ TE)@ and may contain a Local Area Network (LAN)@ routers@ etc. Figure 1 includes equivalent ITU-T terms in parentheses (Teleservice and Bearer Service). A Teleservice provides a complete user-to-user communications capability@ while Bearer Services provide the transport of signals between network interfaces@ and do not include the customer's terminal equipment or local network. Furthermore@ the Network Interface shown in Figure 1 is equivalent to the ITU-T user-network interface. All networks in the Figure are not necessarily identical@ especially in regards to the position of functions such as authentication and billing. Resources (e.g.@ capacity) may be reserved on some networks comprising the connection@ and not on others. Some networks may not be IProuted networks@ e.g.@ dedicated lines@ frame relay networks@ and other networks where routers are not present within the administrative boundaries (shown as [R] in Figure 1). The user-to-user QOS is dependent on the quality and performance of all components that work to establish@ or comprise the media connection. This standard will identify objectives for the user-to-user connection@ and allocate portions to the Customer Installation (TE and LAN) and end-end network components.There are different suppliers for terminal equipment and network services@ and the allocation will assure that the intended user-to-user performance levels are achieved. It will not allocate portions to individual network providers. The following are intended uses for this standard: 1. Network planning. 2. Network and Customer Installation component development. 3. User-to-User connection planning. In connection with User-to-User connection planning activities (item 3)@ it is necessary to stipulate the desired system type(s). Further@ there are cases where certain measurement procedures must be agreed to in advance@ since the standardized measurement coverage was incomplete at the time this standard was developed. Although this standard specifies IP network performance parameters@ some Non-IP services procured must be evaluated using alternate parameter sets. Draft ITU-T Recommendation I.381@ in development at the time this standard was prepared@ provides a mapping between the IP layer and lower layer parameters. Another consideration is whether the Acceptable Level specified in this standard is the goal. When referenced for procurement purposes@ the purchaser should specify which values of tables 5 through 12 apply.