IS-IS = Intermediate System to Intermediate System
CLNP = Connection-Less Network Protocol = Layer 3 network protocol that is used to communicate between ESes. CLNP offers a CLNS (Connection-Less Network Service). CLNP uses NSAP (Network Service Access Point) addressing. An NSAP address is assigned to an entire node, not to individual interfaces.
SNPA = Sub-Network Point of Attachment = Layer 2 address
Local Circuit ID = When added to the ISIS protocol, each interface gets Local Circuit ID. Values: 1-255.