The technology of the Layer-3 switch is becoming more and more mature, and its application is becoming more and more extensive. In a certain range, it has more advantages than routers, but Layer 3 switches are still very different from routers. In local area networks, Layer 3 switches have obvious advantages.
What is a Layer-3 Switch
A Layer-3 Switch is a network switch with some router functions. The most important purpose of a Layer 3 switch is to speed up the data exchange within a large local area network. The routing function it has is also for this purpose, and it can achieve one routing and multiple forwarding. Regular processes such as data packet forwarding are implemented by hardware at high speed, while functions such as routing information update, routing table maintenance, routing calculation, and routing determination are implemented by software. Layer 3 switching technology is Layer 2 switching technology + Layer 3 forwarding technology. The traditional switching technology operates in the second layer of the OSI network standard model – the data link layer, while the three-layer switching technology realizes the high-speed transfer of data packets in the third layer of the network model. It can not only realize the network routing function but also achieve the optimal network performance according to different network conditions.
Advantages of Layer-3 Switch
1. The transmission bandwidth between subnets can be allocated arbitrarily
In traditional routers, each serial port can be connected to a subnet, and the rate of this subnet transmitted through the router is directly limited by the interface bandwidth. The difference is that the Layer 3 switch defines multiple ports as a virtual network (VLAN), uses the virtual network composed of multiple ports as a virtual network interface, and sends the information in it to the third layer through the ports that make up the virtual network. Switches, because the number of ports can be specified arbitrarily, the transmission bandwidth between subnets is not limited.
2. Reasonable allocation of information resources
Since the network system connected by Layer 3 switches has no difference between the resource rate for accessing the subnet and the resource rate for accessing the global network, it is meaningless to set up a separate server. By directly establishing a server group in the global network, under the premise of ensuring the transmission rate of the broadband intranet, it can not only save costs, but also make full use of the software and hardware resource advantages of cluster servers, and can more reasonably configure and manage various information resources. This problem is difficult to solve in router networking.
3. Reduce costs
In enterprise network design, because people usually only use two layers of switches to form the same broadcast domain subnet, and use routers to connect each subnet, the enterprise network forms an intranet, and routers are expensive, so enterprises that support intranets Networks cannot reduce equipment costs. Now, in the inline network system, people use Layer 3 switches for network design, which can not only divide the virtual subnet arbitrarily but also complete the communication between subnets through the Layer 3 routing function of the switch. , that is, the establishment of subnets and inline subnets can be done through switches, which greatly saves expensive routers.