A new routing technology has emerged, which is the third layer switch technology. A three-layer device based on this technology, if called a "router", is because it can operate in the third layer of network protocols and is a routing understanding device that can play a role in routing decisions.

If it is a network switch, it is because its speed is extremely fast, almost reaching the speed of the second layer switch. The improvement of the user network application level is one of the main driving forces for promoting the large-scale application of layer 3 switches.

Users are no longer satisfied with the basic functions of an enterprise switch, which involves connecting input and output ports to forward business flows. In addition to requiring exchange, authentication, and packet filtering functions, they also hope that the switch has routing processing functions; The different applications of users also pose new requirements for the resilience of the network.

At the same time, with the rapid expansion of network scale and the continuous increase of applications in the network, user networks must strengthen control over visitors, restrict illegal user communication, and ensure the security of the entire network, such as the security management of devices in campus networks, the requirements for secure access in resident networks, and the isolation between various businesses in the enterprise network.

However, ordinary switches cannot effectively isolate data transmission between nodes in the network and control user access permissions, posing a threat to the security of the user's local area network.

The third layer switch can provide policy-based security access mechanisms through various explicit or implicit VLAN partitioning methods, improving network security and effectively suppressing the occurrence of broadcast storms.