I.371 (Ref. 13): 1. Network Resource Management (NRM). Provision is used to allocate network resources in order to separate traffic flows in accordance with service characteristics. Connection Admission Control (CAC). This is defined as a set of actions taken by the network during the call setup phase or during the call renegotiation phase in order to establish whether a VC or VP connection request can be accepted or rejected, or whether a request for reallocation can be accommodated. Routing is part of CAC actions. 3. Feedback Controls. These are a set of actions taken by the network and by users to regulate the traffic submitted on ATM connections according to the state of network elements. 4. Usage/Network Parameter Control (UPC/NPC). This is a set of actions taken by the network to monitor and control traffic, in terms of traffic offered and valid- ity of the ATM connection, at the user access and network access, respectively. Their main purpose is to protect network resources from malicious as well as unintentional misbehavior, which can affect the QoS of other already established connections, by detecting violations of negotiated parameters and taking appropriate actions. 5. Priority Control. The user may generate different priority traffic flows by using the CLP. A congested network element may selectively discard cells with low priority, if necessary, to protect as far as possible the network performance for cells with higher priority (Ref. 13). Figure 20.15 is a reference configuration for traffic and congestion control on a B- ISDN/ATM network. 20.12 TRANSPORTING ATM CELLS Network A Inter-network Network B interface B-NT2 B-NT1 Others Others Usage parameter control Connection admission control Priority control Network parameter control B-NT2 B-NT1 Resource management Others For further study Notes: 1 NPC may apply as well at some intra-network NNI's. 2 The arrows are indicating the direction of the cell flow. Figure 20.15 Reference configuration for traffic control and congestion control. [From Figure 1