What is the role of boundary routers in a network?

Boundary routers play a crucial role in managing the flow of traffic between an internal network and external networks, such as the internet. Their primary function is to advertise routes for external hosts, which facilitates the movement of data to and from different networks. By using Border Gateway Protocol (BGP), boundary routers share routing information with other external routers, ensuring that data packets are routed efficiently across the various networks. This capability is essential for maintaining connectivity with external services, providing a pathway for resources and communication between remote locations.

In contrast, filtering local traffic typically occurs at other points within the network, such as firewalls or internal routers, which handle traffic within the same organizational domain. While advertising internal routes is important for the functioning of the internal network, it is not the main task of boundary routers. Network authentication is commonly managed by dedicated authentication servers or protocols, rather than routers. Thus, the border router's focus on external route advertisement is what distinguishes its role within the overall network architecture.