Mesh networks provide natural link and node fault tolerance and load balancing characteristics. However, existing solutions for real-time flow allocation seldom utilize those advantages. This paper deals with the real-time flow allocation problem in mesh networks. The objective is to find the suitable path under delay constraint while allowing load balancing. For this purpose, combined online flow admission control and pathfinding algorithms have been developed on an SDN-like controller. At switch level, each output port is ruled by a credit-based weighted round robin, allowing isolation of flows. As a consequence, a freshly admitted flow will not influence existing flows, allowing incremental online admission of new flows. This approach has been applied to a RapidIO mesh network example and compared with the compositional performance analysis method. Numerical results clearly show the benefit of our proposal in terms of complexity and delay bound pessimism.