Label space reduction based on LSP multiplexing in MPLS Openflow hybrid network

Abstract In MPLS network, each Label Switch Path (LSP) must be identified with a unique forwarding label in each network element. In recent years, with the continuous development of public cloud services, virtual private networks, and mobile computing, the label consumption in MPLS network is expanding rapidly, leading to increased management complexity, expanded ISP operational and capital expenditure, more router table look-up latency, and reduced network performance as well as scalability. To solve these problems, the label space reduction problem (LASPARED) has been presented and studied to optimize the planning of LSPs in MPLS network, so that the number of labels used in the network can be minimized. Label merging and tunneling are two main ways to solve this problem. However, both of the methods have limitations and need to be further improved. In this paper, different from merging and tunneling, we propose a third way to solve LASPARED problem in an MPLS Openflow hybrid network scheme: LSP multiplexing. With the network programmability and packet-editing capability provided by Openflow, we use label stacking and TTL to control packet switching between different LSPs, so that traffics with different source and destination may be able to share the same LSP. Analysis and simulations show that, compared with merging and tunneling, our method can achieve the best label reduction effect as well as the least number of LSPs regardless of topology structures.