Abstract: Layer 3 switching technology is a combination of Layer 2 switching technology and Layer 3 routing and forwarding technology. Traditional switching technology operates at the data link layer, while Layer 3 switching technology achieves high-speed forwarding of data packets at the network layer. The application of layer 3 switching technology can achieve the function of network routing and achieve optimal network performance according to different network conditions. The most important purpose of a three-layer switch is to increase data exchange within a large local area network and cannot replace the work of routers. It is used to replace routers in the interconnection of various subnets in the same local area network and the routing between Vlans in the local area network, while only the local area network and the public network interact with each other
Layer 3 switching technology is a combination of Layer 2 switching technology and Layer 3 routing and forwarding technology. Traditional switching technology operates at the data link layer, while Layer 3 switching technology achieves high-speed forwarding of data packets at the network layer.
The application of layer 3 switching technology can achieve the function of network routing and achieve optimal network performance according to different network conditions. The most important purpose of the three-layer switch is to increase the data exchange within the large LAN, which cannot replace the work of the router. For the interconnection of subnets in the same LAN and the routing between Vlans in the LAN, the three-layer switch is used to replace the router. Only when the LAN and the public network Internet want to achieve network access across regions, professional routers can be used.
After understanding the three-layer switching technology, we now use the VTP technology of switches to achieve communication between different Vlans and networks. The main reason for using VTP technology is that it greatly reduces our management operations on Vlans, making it easy to add, delete, and adjust Vlan configurations in the network to achieve systematic management.
When multiple Vlans are divided on a three-layer switch, and each Vlan uses IP addresses from different network segments, 3500-22M 288055-01 must set the interface IP of each Vlan to enable communication between all computers connected to the switch, and all computers must set a gateway, which is the IP address of the Vlan interface connected to the switch. As shown in the following figure: Topology diagram of the three-layer switch:
Case requirement analysis: Set the core switch as a VTP server and create VLAN 10 and VLAN 20. Set the access layer switch as a VTP client to implement Vlan relay, configure the switch interconnection port as a Trunk type, and plan the VLAN port allocation of the switch to achieve communication between different Vlans and different network segments.
The port modes of switches are mainly divided into Acess type and Trunk type. By default, the port mode of switches is Access type, which can only belong to one Vlan and is usually used to connect computers. Trunk type ports can allow multiple Vlans to communicate and are generally used for switch interconnection.