Registration, resolution and Whois services of .CN and .China (.中国) administered by China Internet Network Information Center (CNNIC) achieved 100% SLA for consecutively three years. 

Service Level Agreement (SLA) is an agreement on technological service quality between the IT service provider and the user. It gives an account of IT service, defines levels of usability, functionality and continuity or other attributes of the service, and specifies responsibility of the IT service provider. Usability of service refers to the normal operation time’s percentage, the core performance measurement index in the SLA. It is a common practice that N9 is taken as a measurement standard for service usability. As for the technical service provider, to achieve 100% of usability not only necessitates advanced hardware, but also requires a scientific procedure system, a flexible mechanism and rapid response to emergency. 

It is the essential responsibility of CNNIC to provide netizens and registrars with first-class service on domain name registration, analysis and Whois technical service. As of 2006, CNNIC has signed with various registrars the SLA that includes 26 items on usability of domain name service, average time in inquiring and modifying domain names, time of DNS registration and duration of its effect, analysis response time, covering the usability indexes on registration and analysis of domain names plus Whois service. Since April 2006, CNNIC Monthly SLA Report was regularly released on the official website of CNNIC, offering phrasal operation analysis on CNNIC technical service, convenient for the public to know more about CNNIC.