Functional Testing of ATM Signalling Protocols Application Note 
Size: 2788 KB
Date: April 2000

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There are generally two parts to making a call within an ATM network. First, the signalling process indicates that a call is to be made, and that network resources should be allocated for this call. Second, the data transfer occurs, which allows the end users or applications to exchange information. The data transfer phase uses the network resources that were allocated during the signalling process to convey voice, data, or video information.

Signalling, in turn, can be broken down into two parts: the signalling that occurs between customer premises equipment (such as a workstation) and the network access device (such as a switch), and signalling that occurs between network switches.

Support for ATM's high-bandwidth applications such as multimedia impacts both the signalling and data transfer phases of the communication process in a significant way-higher complexity. For example, the signalling protocols have become increasingly complicated. In addition, the interaction between the protocols at the user-network interface (UNI) and the network-network interface (NNI) are quite details. And with that complexity comes a more stringent requirement to test the signalling capabilities for correct operation and function.

This type of functional, inter and intra network testing is essential in order to validate the new functions offered by these evolutionary signalling protocols. Not only do these new signalling protocols provide services that are directly useful by the end user, they also provide the basis for new types of services that will rely upon a solid ATM network foundation. Ensuring that these services have been properly implemented now will save testing headaches in the future.

This application note examines the many aspects of signalling through a broadband network, and focuses on the different areas that must be tested in order to create a functional and high performance network. Specific testing concerns will be addressed. Testing methodologies such as conformance and performance testing will also be introduced.