SLI (Service Level Indicator)
A Service Level Indicator is a quantitative measurement used to evaluate whether a service is meeting its Service Level Objectives (SLOs), which in turn underpin contractual SLAs. Common telecom SLIs include availability, packet loss, latency, jitter, and call setup success rate. Modern SRE practice manages reliability through SLO error budgets derived from SLIs.
Categories: Operations and Business
SLI in context
OSS/BSS platforms hold the highest-value subscriber and revenue data on the operator side, are heavily targeted for fraud and insider abuse, and are in scope for NIS2 and the UK Telecoms Security Act.
To place SLI in the wider telecom-security picture, review 3GPP, ARPU, Billing System, BSS, Charging System and Control Plane Security — each entry cross-references back to this page so you can walk the topic in either direction.
Related terms
More from the TelcoSec Glossary
Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.