SIP User-Network Interface Testing Framework
|Publication Date:||1 August 2008|
This Technical Report (TR) describes a framework for testing User-Network IP interconnection for VoIP.
The testing framework described herein is for the SIP user-network interface (UNI) as specified in the ATIS American National Standard Interoperable SIP UNI Specification.  That document is referred to in this TR as the SIP UNI ANS.
A common testing framework has the benefits of
1) re-use, avoiding the inefficiency of pair-wise re-creation by network operators and customer equipment (CE) vendors
2) industry-wide input
3) being a common reference for understanding test results (e.g., when network A tests with customer equipment B and then with customer equipment C)
This testing framework
• addresses pair-wise network-CE interoperability according to the SIP UNI ANS, rather than equipment or vendor testing or certification, or protocol standards conformance
• is agnostic regarding the particulars of test environments and configurations - e.g., it could be with a live network and commercial customer equipment or with a network-emulating lab and beta customer equipment
• does not assume any details about internal network architectures or systems
• describes the kinds of things to be tested, but does not provide explicit, enumerated test cases; and also does not specify particular testing methods This testing framework does not address
• identification of the responsible organization performing the testing
• testing for services; however, services may be used as stimuli to invoke aspects of protocols that are to be tested
• load testing
• simultaneous testing of multiple UNIs between a network and customer equipment. This TR addresses testing of a single UNI at a time.
• failure scenarios
• test cases that intentionally result in a protocol timeout
Successful interoperability testing should be verifiable strictly by observing what happens across the UNI. Test generation and some verification methods may pragmatically involve the placement of actual telephone calls and observing results from that user point of view.
Before defining specific test plans, the network operator and CE operator involved shall agree on what subset of the SIP UNI ANS they are implementing. Testing could follow various models. For example:
a. Conduct a full suite of tests exercising the entire interface as defined in the SIP UNI ANS, and verify which pass. An advantage of this approach is that it can discover capabilities supported across the interface that may not otherwise have been known to or agreed to by the network operator and CE operator.
b. Conduct a test suite that exercises a subset of the entire interface in the SIP UNI ANS, where that subset is limited to aspects of the SIP UNI ANS that are agreed to by the network operator and CE operator. An advantage of this approach is that it may involve less testing. The subset may depend to some degree, for example, on the nature of the IP network or CE.
The exercise of the testing guidelines and call stimulus scenarios contained in this document are intended to have no impact on the integrity or reliability of existing services being supported in a live network.