  This report deals with the design of handover schemes for radio access
networks (RAN) in 5G networks, using programmable data plane switches. In 5G
networks, the NG-RAN architecture splits the Base Band Unit (BBU) into Central
and Distributed Units (CU and DU). This structure has created a mid-haul
Network, connecting CUs and DUs. The recent advancements in dataplane
programmability can be used to enhance system performance. We show how P4
switches can be used to parse the packets between DU, CU, and Back Haul (Core
Network) for potential system improvements. In particular, we consider the
scenario of mobile handover. The proposed protocol is called SMARTHO,
illustrating a smart handover.
  Programming Protocol-Independent Packet Processors (P4) is a programming
language designed to support specification and programming the forwarding plane
behavior of network switches/routers. In SMARTHO, we use P4 Switches to
intervene in the handover process for fixed-path mobile users. A resource
pre-allocation scheme that reserves resources before the UE reaches a future
cell, is proposed. The solution is implemented using a P4-based switch
introduced between the CU and the DU. The P4 switch is used to spoof the
behavior of User Equipment (UE) and perform the resource allocation in advance.
  The proposed SMARTHO framework is implemented in the mininet emulation
environment and in a reconfigurable hardware environment using NetFPGA-SUME
boards. The emulation results show a handover response time improvement of 18%
for a tandem of two HOs and 25% for a tandem of three HOs. For testbed
implementation, we used NetFPGA-SUME boards as P4 switches. The handover time
was measured to be approximately 50~milliseconds in the experiments conducted.
