Modules and interface cards are specifically for high-end modular routers and switches. For routers and switches with fixed configurations, modules and interface cards are not applicable. Usually, network modules are developed to expand the functions of local area networks, while interface cards mostly refer to wide area network interface cards. Through wide area network interface cards, router and switch products can conveniently achieve more efficient wide area network access. Products with modular design have the advantage of effectively protecting user investment, truly realizing on-demand purchase, and at the same time, the products can be strongly expanded to meet the needs of continuous business expansion.