These settings are the traffic descriptor for the connection. The nrt-VBR service category is used for routes that carry variable passenger traffic, for which there is no inherent dependence on the temporal synchronization between the traffic source and the destination, but an attempt at guaranteed bandwidth or latency is required. One application that may require a nrt-VBR service category is Frame Relay interworking, in which the Frame Relay CIR (Committed Information Rate) is associated with a bandwidth guarantee on the ATM network. There is no delay limit for the nrt-VBR service.  Each ATM link contains a series of parameters that describe the traffic characteristics of the source. These settings are called source traffic settings. They are : ASA covers the basic framework whereby airlines enjoy bilateral economic flight rights in two countries. Frequency, designated airlines of the two signatory states, points of origin and intermediate points, traffic rights, type of aircraft and tax issues are generally covered by soft. (3) The freedom to transport air traffic between countries other than the country of origin of the aircraft. ABR uses resource management (RM) to provide feedback that controls the data source in response to fluctuations in available resources in the internal atmic network. ABR flow control specifications use these RM cells to control cell flow based on the flow effect on ABR connections.
The ABR service expects the terminal system to adjust its traffic rate based on feedback, so that it gets its fair share of available network resources. The goal of the ABR service is to allow quick access to available network resources up to the specified peak cell rate (PCR).  There are currently five categories of services defined by the ATM forum (see Table 1). The fundamental differences between these categories of services are described in the following subsections.   These categories of services offer a method to link traffic characteristics and QoS requirements with network behavior. Service categories are characterized as real-time or non-real-time categories. CBR and rt-VBR are the real-time service categories. The other three categories of services (nrt-VBR, UBR and ABR) are considered non-time service categories. The Rt-VBR service category is used for connections that carry traffic at varying speeds – traffic based on precise timing between source and destination.
An example of traffic that requires this type of service category is the variable rate, compressed video streams. Sources using rt-VBR connections should be transferred at a variable speed over time (for example. B, data traffic, which can be considered bursty). Real-time VBR connections can be characterized by peak cell rate (PCR), sustained Cell Rate (SCR) and Maximum Burst Size (MBS).