Telecom service assurance is software that watches whether a telecom operator's network is serving its subscribers well: whether calls connect and stay connected, whether data is fast, and whether videos start quickly. It is also called service quality monitoring, or network performance management. It watches the network, but it does not run it.
An operator's network produces huge amounts of data about itself. Every radio site counts its connection attempts, dropped calls and data speeds, usually every 15 minutes. These counts are called KPIs, or key performance indicators. The packet core, the part of the network that connects phones to the internet, keeps a record of every data session. Service assurance software collects all of this, from equipment made by many different companies. It stores it, compares it with targets and shows engineers where the service has become worse.
Who sets the targets? Partly the operator itself, and partly TRAI, the Telecom Regulatory Authority of India. TRAI sets quality-of-service standards, such as the highest share of calls that an operator may drop, and publishes how each operator performs against them. So operators watch these numbers closely.
Consider an operator in Tamil Nadu that upgrades the software on its radio sites in Madurai one night. The upgrade comes from the supplier of its RAN software. The RAN, or radio access network, is the part of a mobile network that includes the towers and the radio equipment on them. The next morning, the service assurance dashboard shows a change. At 38 of the 210 upgraded sites, the share of dropped calls has risen from 0.6% to 2.3%. Download speeds at those sites have fallen by a third. At the other 172 sites, nothing has changed. The engineers look at the 38 sites together, and see that all of them use one older model of radio unit. So the new software does not work well with that model. The operator puts the old software back on those 38 sites by the evening, and asks the supplier for a fix.
Without this software, the operator might have learned of the problem from subscribers' complaints, days later. Many operators also measure the subscriber's experience directly. Test phones placed around a city make test calls and load test pages, and report the results.
Service assurance compares the live network with the results of network test equipment, which show how each site performed when it was new. Its data helps network planning software decide where new sites are needed. When hundreds of alarms arrive at once, network AIOps groups them into one likely cause.
How is it different from the operator's own operations software, the OSS? The OSS runs the network. It sets up equipment and switches on services for subscribers. Service assurance only watches and reports. It is the telecom operator's version of an observability platform.