A zero-hop protocol is one which is designed not to be forwarded by a router. This protocol could be expected to set IP.TTL to 1 (the router won't drop the packet just because IP.PROTOCOL=114). These protocols used to be commonplace in the era before internets (DEC LAT,etc). But the advantages of a protocol _able_ to be globally routed are just too great for zero-hop protocols to be of much modern interest (even if in some deployments you might choose to limit the packets to one subnet). You can see IANA felt the same, calling out all zero-hop protocols, not just a particular one.