Laying the foundation for multi-layer exchange technology has become the core of future development

At present, there is no specific standard for layer-7 switching functions. At the same time, the biggest advantage between layer-7 switching and some similar solutions is the biggest advantage of multi-layer switching technology, that is, high speed does not affect Intelligent Processing. Multi-layer switching technology will certainly drive the development of the network. As a core technology of the future network, it will also lay a solid foundation for scalable solutions for multiple applications in the future. The development of data exchange technology from simple circuit exchange to L2 exchange is just a few years from L2 exchange to today's mature L3 exchange.

After this layer-3 Exchange, the concepts of layer-4 Exchange and layer-7 exchange come one after another, the development of multi-layer switching technology has already reached the "management point". OSI divides the computer network architecture into seven layers ). The rapid development of computer network acceleration is amazing.

Layer-3 switching enables high-speed packet forwarding

Multi-layer switching technology has been widely used in LAN construction and transformation from bridging to VLAN Virtual LAN. Layer 2 switching technology is the Layer 2 that works in the OSI Layer 7 network model, that is, the data link layer. The disadvantage of L2 switching is that the broadcast domain is too large and data exchange between subnets of different IP addresses cannot be processed. This type of network structure is flat and has no hierarchical concept. Therefore, to use the advantage of high forwarding efficiency on Layer 2 and Process Layer 3 IP data packets, Layer 3 switching technology is born.

Layer-3 switching technology, also known as multi-layer switching technology or IP address switching technology, is named after the layer-3 that works in the standard OSI Layer-7 network model. The emergence of layer-3 switching technology solves the problem that the subnet must be managed by routers after the network segments are divided in the LAN, and solves the network bottleneck caused by the low speed and complexity of traditional routers. Like a common L2 Switch, a l3 switch also maintains an address table for L2 switching, which is usually called a CAM table. This table is the correspondence between the MAC address and the outbound interface. In this way, each time an Ethernet data frame is received, the layer-3 Switch determines that if the data frame is not sent to itself, It queries the CAM table based on the target MAC address of the data frame. If hit, the query result is usually an output interface list for forwarding. If the data frame cannot be hit, the data frame is broadcast to all ports.

Layer-3 switching is safer

Currently, L3 switches, especially high-end L3 switches, it has greatly improved routing forwarding capabilities, interface types, service capabilities, QoS, security, billing, authentication, and other functions. In terms of routing and forwarding capabilities, traditional switches are limited by the CACHE capacity. For example, when the network size increases and the number of network addresses increases, there is a risk of CACHE depletion, in particular, due to the proliferation of viruses on the network, more and more attacks are being initiated against forged addresses. A large number of forged IP addresses will soon exhaust the resources of switches. Therefore, a high-end Layer-3 Switch uses the "Longest match" method similar to a router, that is, it does not match the complete IP address and only performs the longest match based on the network segment, in this way, we can better adapt to the changes in the network scale and traffic mode. At the same time, due to the development of ASIC Technology, this "Longest match" can also be completed by hardware, so that layer-3 switches can adapt to more complex network environments without affecting the forwarding speed.

Today, with the proliferation of viruses and attacks, network security issues become more and more important. To solve security problems, you must support illegal traffic filtering and user authentication at the edge of the network. Currently, all layer-3 switches support configuring ACL policies. You can filter illegal data streams based on traffic characteristics or use traffic restriction policies, in this way, the spread rate and harm Degree of virus or attack traffic are greatly restricted.

Multi-layer switching to top layer

The rapid development of the Internet accelerates the rapid increase of information, which puts a great deal of pressure on the Network Information Center Server. The layer-4 switch came into being in the face of pressure relief from the network core system. When a layer-4 switch differs from a layer-3 switch, it not only applies the IP exchange technology in the layer-3 switch, but can view the content of the layer-3 data packet header source address and destination address, you can take appropriate actions based on the observed information to achieve bandwidth allocation, fault diagnosis, and access control for TCP/IP application data streams.

In addition to Server Load balancer, layer-4 Switching also supports other functions, such as application type and user ID-based transmission flow control. Using Multi-Level queuing technology, the layer-4 switch can mark the transmission stream and assign priority to the transmission stream based on the application. In addition, the layer-4 switch is directly placed on the front end of the server. It understands the application session content and user permissions, making it an ideal platform to prevent unauthorized access to the server. What's even more surprising is that the current switch technology has an impact on the seventh layer. The intelligence of the seventh layer can be further controlled, that is, control of all transmission streams and content.

Currently, there are no specific standards for layer-7 switching. However, the biggest advantage between layer-7 switching and similar solutions is that the multi-layer switching technology has the highest speed and does not affect Intelligent Processing. Users can use multi-layer switching technology to make more intelligent decisions on Transmitting stream content at the exchange speed. Layer-7 switching achieves effective data flow optimization and intelligent load balancing. Users can make decisions on various transmission streams and their destinations based on the obtained information, so as to optimize network access and provide better services for end users.

Intelligent Multi-layer switch-driven routing

The rapid popularization of networks has led to a wide range of applications, and users' demand for bandwidth is always far higher than the development of bandwidth itself. Therefore, the smart devices behind the network infrastructure such as vswitches and routers must be more intelligent to meet users' bandwidth needs.

In many large enterprises, it is usually divided into subnets that implement interconnection through routers. This classification is generally based on the region, the type of running application, the required data volume, and security factors. Because the design and implementation of group forwarding of traditional routers are based on software, grouping processing takes many steps during the forwarding process, and the forwarding process is complicated, making the forwarding rate slow. In addition, various additional security measures in the vro increase the CPU burden, which makes the vro a bottleneck on the Internet. Therefore, there is a new technology called "multi-layer switching routing" in the industry. These "smart" switches/routers can provide faster speed and shorter latency, it can also combine the functions of multiple network devices. It adopts a new network design and management mode. When line rate Forwarding is implemented today, congestion points can be effectively eliminated, and users can be farther away from data without worrying about performance degradation.

The functions of multi-layer switching routing are no different from those of traditional routers and switches. They only concentrate the scattered LAN and man functions on a single device. At the same time, it can realize local exchange between users in the same group, that is, layer-7 exchange. Implements routes between users in different groups, that is, layer-2 switching or routing. It also provides security features and special services for applications, that is, layer-4 switching. Multi-layer switching technology will certainly drive the development of the network. As a core technology of the future network, it will also lay a solid foundation for scalable solutions for multiple applications in the future.