WT2100L redundant link tester can efficiently complete the measurement of redundant link switching speed and verification of redundancy functions of system. Each tester contains 4 (8 RJ45 ports) 10/100/1000M adaptive Ethernet links, each link has Ethernet high-speed switches at both ends, and the on/off of the FPGA switch can easily and quickly control the connection and disconnection of the physical link. The two adjacent links can be the primary and backup links of each other, and the switching time of the primary and backup links can be accurately measured, and the test results can be exported for comparative analysis.