The JANET NRS (Name Registration Scheme) was a hierarchical naming scheme adopted for use on United Kingdom academic and research networks before the similar system used by the Internet DNS had been fully established. JANET is a British, private, government-funded computer network dedicated to education and research. ... The Domain Name System (DNS) is a system that stores information associated with domain names in a distributed database on networks, such as the Internet. ...

The principal difference was that the order of significance began with the most significant part (so called Big-endian addresses). For example uk.ac.cam rather than the Internet-style cam.ac.uk. When integers or any other data are represented with multiple bytes, there is no unique way of ordering of those bytes in memory or in a transmission over some medium, and so the order is subject to arbitrary convention. ...

For email, interoperability between the "Grey book" email addressing style of user@uk.ac.site and Internet addresses of the style user@site.ac.uk was achieved by way of mail gateways. However, problems were caused when the least significant part of an Internet address matched the most significant part of an NRS address and vice-versa.

JANET later transitioned to using the Internet standard for addressing, and the final mail gateway had been taken out of service by the end of 1997. 1997 (MCMXCVII) is a common year starting on Wednesday of the Gregorian calendar. ...