In this paper, we propose an Ethernet-based transmission-guaranteed, congestion-controlled network using a simplified multi-path aggregation scheme. Multi-path aggregation increases throughput by multiplying the bandwidth of a single path by the number of paths. There are several aggregation schemes, such as Link Aggregation and Multi-path TCP. However, Link Aggregation is unable to utilize multiple paths to increase throughput because it distributes a single flow only into a single path, The Multi-path TCP scheme requires managing two stages of sequence numbers (SEQ) (i.e., the SEQ assigned to a path and the SEQ assigned to the flow). This complexity requires software-based implementation, which means the method fails to provide high throughput and short latency. We therefore propose a single-stage sequence number scheme with a reorder-buffer-usage-based retransmission-activating algorithm. Hardware implementation of this scheme is very simple. In addition, packet-loss detection is rapid. Our simulation and experimental results showed that our scheme provided a high-throughput, short-latency, and transmission-guaranteed network over conventional, lossy, delay-fluctuated, and best-effort Ethernet.