The route server function is similar to the RR function in IBGP scenarios and allows devices to advertise routes to their clients (ASBR devices) without changing route attributes, such as AS_Path, Nexthop, and MED. With the route server function, EBGP full-mesh connections are not required among the ASBR devices, which reduces network resource consumption.
In some scenarios on the live network, to achieve network traffic interworking, EBGP full-mesh connections may be required. However, establishing full-mesh connections among devices that function as ASBRs is costly and places high requirements on the performance of the devices, which adversely affects the network topology and device expansion. In Figure 1, the route server can advertise routes to all its EBGP peers, without requiring EBGP full-mesh connections among ASBRs. Therefore, the route server function reduces network resource consumption.