Connectionless Network Service (CLNS)

Connectionless Network Service (CLNS) is an International Organization for Standardization (ISO) Layer 3 protocol, similar to IP version 4 (IPv4). CLNS uses network service access points (NSAPs) to address end systems and intermediate systems. A single routing domain consisting of ISO NSAP devices is considered to be a CLNS island. CLNS islands are connected together by VPNs.