Research on the centralized test system for users in Softswitch networks

This article mainly discusses the functions, testing methods, construction scheme, and relationship with other systems of softswitch network user fault centralized testing system.

1. Preface

The centralized user Fault test system is a service support system for telecom operators to handle user fault reports. It aims to improve service quality, ensure the normal operation and maintenance of lines, and reduce maintenance costs, improve maintenance efficiency. Therefore, the construction of a centralized Test System for user faults plays an important role in telecom service quality. At present, carriers are deploying large-scale Softswitch networks. The softswitch network has the characteristics of separation of bearer and control, and separation of business and control. Compared with the traditional switching network, the softswitch network has multiple user access methods and types, therefore, a new requirement for the centralized Test System for user faults is put forward, which will be discussed in this article.

2. User fault centralized test system architecture and main function modules

2.1 user fault centralized Test System Position in BOSS

There are two main types of information systems for telecom enterprises: MSS (Management Support System) and BOSS (Business Operation Support System ). BOSS is a unique information system of telecom enterprises and an indispensable part of Telecom's daily operations. It also provides MSS with information sources for management and decision-making. BOSS focuses on operational support and readiness and FAB (Business activation, service assurance, and billing) in the enhanced telecom operation diagram (eTOM) model. It can be divided into BSS (businesssupport system. Business support system) and OSS (operation support system). Each part is composed of multiple systems with relatively independent functions. BSS mainly refers to front-end support systems for businesses and customers, such as most modules of the "97" system (with the continuous upgrade of the "97" system, currently, the customer relationship management and business systems have been gradually incorporated into the "97" system) and billing and accounting systems. OSS is a back-end O & M Support System for telecom businesses, including the Network Element/network management system, cable monitoring, resource management and scheduling, and business support system for telecom networks. The centralized Test System for user faults is part of OSS service assurance, as shown in 1.

Figure 1 position of the user Fault Test System in the BOSS

2.2 System Architecture

The architecture 2 of the centralized Test System for user faults is shown in. In the figure above, the APP (ADSL port Protocol) is in the ADSL test. The protocol used by the test server to query ADSL port information from the network management system, including query of user information of various DSLAM (digital user line access multiplexing, control the DSLAM test bus and the tested user port self-loop diagnosis test. In the figure, SNMP is a Simple Network Management Protocol, and TL1 is a transactional language 1.

Figure 2 architecture of the centralized Test System for user faults

The centralized user Fault test system is divided into two parts: the Central Business System and the local test system by device location:

● The central business system includes an electronic ticket system for Fault Handling and handling, and a test server. . The e-ticket system is responsible for accepting user fault reports and management and handling processes, and copying user line information from the "97" system. The test server is the test executor. It obtains user port information (busy/idle) from the softswitch network management system and provides test commands for the uplink interface, and control the width/narrow band Testing Device for wire capturing. The test server processes and summarizes the test results and determines whether to report the results to the network management system.

● The local testing system includes broadband/narrowband testing devices and local operating terminals. It provides testing head testing, network management simulation testing, PC self-diagnosis, and other testing methods, it also provides multiple testing functions such as line pre-evaluation, end-to-end full obstacle testing and handling, and routine testing.

The centralized Test System for user faults can be divided into two parts by function: "E-Ticket System for Fault Handling" and "centralized Test System", as shown in figure 3. The former is responsible for the control of the entire process of troubleshooting, the latter is responsible for the specific testing of user faults, and the former calls the latter.

Figure 3 user Fault test system function module

The E-Ticket System for Fault Handling includes centralized automatic acceptance of user obstacle statements, centralized automatic and manual repair, centralized management, and databases.

Centralized testing system includes POTS (traditional telephone service) such as automatic testing by users, automatic testing of ADSL user faults, automatic testing of SIP hardware terminals/IAD, self-check by PC, Test Control, test result analysis, Network Element Management, and query of control information.

The user test features of the softswitch network are mainly concentrated in the centralized test system. Therefore, the "centralized Test System" is discussed below. Similar to traditional network functions, the "fault acceptance and handling Electronic Ticket System" section will not be described in detail.

 

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3. Test Method of softswitch network users

As the softswitch network is characterized by separation of bearer and control, and business and control, the call control (Softswitch) and gateway (user line) in the softswitch network are separated, and the softswitch itself does not have a user line. The centralized Test System for user faults in the softswitch network needs to test various direct users: users under AG (Access Gateway) (POTS users, ISDN users, ADSL users), IAD users, the test method of the SIP hardware terminal is described as follows.

3.1AG user testing

AG users are divided into narrowband users and broadband users. Narrowband testing projects mainly include intra-Bureau user circuit testing, off-site user line testing, and user terminal testing. User Circuit tests in the Bureau mainly include dial-up audio testing, loop current and receiving number testing, and feed voltage testing. In-site user line tests, the user line voltage resistance tests, user loop current tests, and so on. The narrowband test time must be within 15 s.

Broadband line measurement projects mainly include: frequency response test, time domain reflection test (optional), noise test, DMT (discrete multi-audio debugging) vertical balancing test and inductive coil testing (optional. In addition, the self-diagnosis software for the ADSL Broadband Access PC client should be installed on the user client to test the fault of the user client (including the PC and Modem. Because the ADSL automatic test system cannot diagnose the fault of the user's computer, the PC client self-diagnosis software tests the user's lateral network side, which is a supplement to the ADSL automatic test system. When a user encounters a problem, the user runs the self-diagnosis software first, and the software provides the diagnosis results and troubleshooting methods. If the user can solve the problem, the user can fix the problem on his own. If the user cannot solve the problem on his own, the user can report the repair, this reduces the reporting rate. At the same time, the user informs the receiver of the diagnosis result, which improves the efficiency of fault locating. The PC client self-diagnosis test software can have the following functions: PC configuration check, user network card installation, user PC and ADSLModem are correctly connected, and user ADSLModem is synchronized with DSLAM.

For the AG of softswitch, the user's centralized Fault test system should provide two testing methods: Simulation Testing and testing head testing.

(1) test Headers

The test head test is to use the test head device to cross-connect to the AG test bus for testing. Its structure is 4 shown. During the test, the user Fault test system first queries the AG user port status information through the network management system, connects the test bus to the test user line, and then completes the test by an external test head device.

Figure 4 AG testing head Testing Method

In this test mode, you can control the internal and external lines of the test bus through the network management system (the section from the testing device to the local terminal belongs to the internal line, and the section from the user end belongs to the external line) switch between them to complete testing of AG internal user circuit and user external line.

(2) Simulation Test Method

The user's centralized Fault test system can also perform a simulation test, that is, testing through the built-in test chip in the AG device. In this test mode, the test system does not need to connect to the device's test bus. Instead, it only needs to connect to the softswitch network management through the TCP/IP protocol and control the AG through the network management system to complete the test, implementation Method 5.

Figure 5 AG Simulation Test Mode

The advantages and disadvantages of the two test methods are shown in table 1.

Table 1 Comparison of two test methods

The Testing Method of the test header is highly accurate and fully functional. In addition, the test speed is fast, which is suitable for scenarios with a large and concentrated number of users, but the cost is high. The simulation test method makes full use of AG's original test resources, without additional test headers. The cost is low, but the test