SQM: A New O&M Experience for PTN

Packet transport network (PTN) is an important bearer solution for metropolitan area networks. PTN provides 2G/3G backhaul, WLAN hotspot access, and dedicated line access for VIP group users. The fast-growing demand for 4G LTE has meant that more PTNs have to be constructed.

The need to uniformly carry all types of integrated services, especially LTE services, has increased O&M requirements of PTNs. The biggest challenges for PTN O&M are ensuring efficient service deployment, quality service transport, and rapid fault location.

Challenges of PTN O&M

When PTN is used to carry LTE and dedicated VIP group users, higher service bandwidth and network performance are required. Delimiting responsibilities and locating and diagnosing faults can also be more difficult. The challenges related to PTN O&M—which includes O&M during network deployment, routine O&M, and fault maintenance—are ever greater. 

An LTE network requires high-performance transmission between eNBs and a core network and between eNBs themselves. LTE eNB deployment and site adjustment involves establishing and scheduling many PTN-based backhaul channels, and it is difficult to accurately determine whether the newly deployed channels meet the bearer requirements of LTE eNBs. 

During routine maintenance, operators often find that they receive user complaints even though the network KPIs indicate that the network is running well. This means that traditional KPIs obtained from the network management system do not truly reflect the actual network QoS and do not prevent service experience declining when network performance declines.

Traditional O&M is divided into several maintenance domains according to a specific private network, so it is often insufficient for handling complaints about 3G, LTE, and dedicated line services in a timely manner. Faulty nodes are difficult to locate quickly, and faulty private networks cannot be accurately delimited. This results in a long fault handling process that affects customer satisfaction.

SQM Solution

To cope with the challenges of PTN O&M, ZTE has joined operators in researching key O&M requirements and has developed a service quality management (SQM) system. The SQM system is centered on network and service performance management to authenticate and control QoS, and also quantify, compare, and test QoS indicators.

The SQM system deployed in the PTN can analyze network and service performance and optimize the O&M procedure. It has the following features:

●    A distributed performance measurement system that primarily uses active performance measurement but also passive performance measurement can accurately measure PTN and service performance.

●    The embedded RFC2544, Y.1564, Y.1731, and TWAMP testing functions supports origination, transparent transmission, and reflection of measurement flow, fully covering end-to-end measurement of L2 link performance and L3 service performance in the PTN.

●    The SQM system supports end-to-end performance testing on any service link and link-by-link performance testing on specified links in the PTN in order to meet the need for long-term QoS monitoring of important links and the need for rapid fault location.

●    The SQM system measures online service quality on a real-time basis and provides visual quality management based on typical PTN service granules, including presentation, alarms, analysis, and reports in order to meet the need for controllable service quality.

SQM Applications

LTE network construction and guaranteeing service for group users are an operator’s top priorities in PTN O&M. Higher requirements for QoS include rapid service channel commissioning, guaranteed 24-hour high-quality channel performance, efficient troubleshooting, and periodic QoS report. SQM is a good solution for these important aspects of O&M. It also provides visual, personalized applications for maintenance personnel, network monitoring personnel, and O&M management personnel involved in the O&M flow.  

Performance Assessment on Newly Commissioned Service Channels

For newly commissioned LTE backhaul channels or dedicated lines for VIP group users, the SQM solution has built-in RFC2544 or Y.1564 testing functions. This means that channel performance can be tested and the quality of L2 or L3 channels can be determined in order to meet service deployment requirements and ensure successful service provision.

Real-Time Monitoring of the Performance of Online Services

For online Ethernet services, the SQM solution monitors channel performance in real time through the embedded Y.1731/TWAMP test. Service performance is shown visually so that the status of services inside the bearer channels is clear and alarms can be raised immediately if channel performance deteriorates.

Rapid Fault Location

For complaints about wireless and dedicated-line service faults, the SQM solution provides active fault measurement and location oriented to service applications. Through link-by-link measurement and quality analysis of service paths in the PTN, faulty nodes are rapidly and exactly located and failure worksheets are efficiently implemented.

SLA Service Management

For service guarantee of hotspot eNBs and important dedicated lines, the SQM solution provides 24/7 uninterruptible performance monitoring and makes a statistical analysis on key indicators based on the SLA. The solution also outputs SLA reports to improve customer service satisfaction.

With the growth of full-service operation, operators are enhancing their operation support capabilities. SQM is crucial in a competitive era. SQM is strategically important. Operators can adopt SQM step-by-step in private networks according to their own network resources, business development, and organization structure, and finally implement SQM throughout the network.