The University of Bristol has a high national and international participation in the area of Software Defined Networking (SDN). The group's facilities are comprised of feature-rich SDN testbeds, offering a wide variety of capabilities. The following elements are included in the SDN testbeds:

a) SDN Controllers: (OpenDaylight, Ryu): Control-plane OpenFlow library extensions and SDN Controller extensions to support heterogeneous resources (different optical & packet technologies).

b) Applications: Virtual PCE with routing algorithms (RWA/RSA). Traffic Engineering (segregation of Elephant/Mice flows based on application characteristics). Virtualisation algorithms.

c) OpenFlow Agents: OpenFlow-based Hardware Abstraction software stacks which can facilitate unified integration of different types of network hardware elements (Optical, FPGAs, WiFi...).

d) Network Orchestrator: Dynamic application based wan connections operation over multiple domains.

e) Resource Abstraction: Comprehensive resource representation models were designed to describe programmable attributes of the underlying heterogeneous devices (Optical, Packet, FPGA etc.).