A Routable protocol is a network protocol which can carry data from one network and can pass through the router to reach another network and be delivered to a computer in that remote network.
Examples of routable protocols: Internet Protocol (IP -IPv4 and IPv6), IPX, AppleTalk, VINES Internetwork Protocol (VIP), DECnet
A non-routable protocol’s data cannot be passed through a router to reach a remote network. This is mainly because of the lack of capability of protocol (almost all non-routable protocols are designed long back which will not fit well in current networks) and the addressing scheme the non-routable protocol is using.
Non-routing protocols reachability limit is its own network and they are designed in such a way to think that all computers they communicate are on the same network as the source computer.
Examples of non-routable protocols: Local Area Transport Protocol (LAT), NetBios Extended User Interface (NetBEUI).