是這樣

1. with only one "router" all clients are on the same ip network. no need for any layer 3 service. the lan interface on the router sees client's ip address is on the same subnet as its own, it just broadcasts arp to get destination ethernet address and send the ethernet packets. why need route?

2. your so-called "路由其" is not a real router. it does not broadcast, nor receive routing info, nor does it keep any routes other than default gateway. $10 router, 路由個屁!