The key activity of EARN was to maintain the BITEARN NODES file, a text file containing the list of all the existing computers (nodes) connected to the worldwide network, as well as information about the contact person at each node, and needed to generate the routing tables for each computer in the network. Each country member (and BITNIC in the US) was responsible to collect, on a monthly basis, the changes affecting its national backbone, providing a list of added and deleted nodes and network links to the master EARN repository via NETSERV, a server accessible via the network, managed at first by IBM engineers and later transitioned to EARN hired engineers.
The DOMAIN NAMES file contained all the information necessary to allow mail exchange between EARN/BITNET and the various different domain-style networks connected to it. EARN/BITNET support of domain-style names was accomplished by using programs that referenced domain routing information tables which mapped domain-style names to network node gateways.
The SERVICE NAMES file contained all the information necessary to map RFC822 style addresses to network servers performing the DISTRIBUTE function (e.g. Listserv).

These 3 key activities were delegated to the GUM-NCC (Global Update & Monitoring Network Coordination Center) by the EARN Board of Directors soon before the merger with RARE.