KEIO University KEIO University KEIO University KEIO University KEIO University This document proposes unified Layer 2 (L2) abstractions for Layer 3 (L3)-driven fast handovers. For efficient network communication, it is vital for a protocol layer to know or utilize other layers' information, such as the form of L2 triggers. However, each protocol layer is basically designed independently. Since each protocol layer is also implemented independently in current operating systems, it is very hard to exchange control information between protocol layers. This document defines nine kinds of L2 abstractions in the form of "primitives" to achieve fast handovers in the network layer as a means of solving the problem. This mechanism is called "L3-driven fast handovers" because the network layer initiates L2 and L3 handovers by using the primitives. This document is a product of the IP Mobility Optimizations (MobOpts) Research Group. This memo defines an Experimental Protocol for the Internet community.