The history of exchange technology from the traditional Layer 2 to layer 7th

There are many things worth learning about the layer-2 exchange technology. Here we mainly introduce the development history of the exchange technology from the traditional layer-2 to layer-7th. Network technology is developing rapidly, and Ethernet occupies a dominant position. In order to adapt to the challenges brought by the deepening of network applications, the scale and speed of the network are rapidly developing. The speed of the LAN has increased from 10 Mbit/s to 100 Mbit/s, gigabit Ethernet technology has also been widely used.

For users, the high reliability, high performance, easy maintenance, and scalability of the network are ensured under the premise of reducing the cost, which is closely related to the networking technology used. For device manufacturers, on the basis of ensuring the realization of the user's network functions, how to make more profits and use the advantages and disadvantages of networking technology has become a means to increase profits.

In the specific networking process, it is to use the mature traditional 2nd layer switching technology, or to use the 3rd layer switching technology with the routing function, or is it possible to use a layer-3 Exchange Technology with a high level of network services? In the trade-offs of these technical choices, the two-layer switching, three-layer switching, and seven-layer switching technologies are superior to each other. What environments are they applicable?

Traditional layer-3 Exchange Technology

Layer-2 switching technology can identify the MAC address information in the data frame, forward the information according to the MAC address, and record the MAC address and the corresponding port in the internal MAC address table. Speaking of exchange, in a broad sense, any data forwarding can be called exchange. However, the traditional, narrow layer-3 Exchange Technology only includes data link layer forwarding. Currently, layer-4 switching technology is mature. From the hardware point of view, the interface modules of the 2nd layer switch exchange data through the High-Speed Backplane/bus speed up to dozens of Gbps, layer-2 switches generally contain Application specific Integrated Circuit chips dedicated to packet forwarding, so the forwarding speed can be very fast.

Layer-2 switches are mainly used in small LAN, with fewer than two or thirty machines. In such a network environment, broadcast packets have little impact, the quick exchange function, multiple access ports, and low costs of a layer-2 switch provide a complete solution for small network users. In short, the exchange LAN technology enables dedicated bandwidth to be exclusive to users, greatly improving the efficiency of LAN transmission. It can be said that in the network system integration technology, the 2nd-layer exchange technology that is directly oriented to users has achieved satisfactory answers.

Layer-3 switching technology with routing functions

The layer-3 exchange technology was a kind of exchange technology that began to appear around 3rd. It was initially designed to solve the problem of broadcast domains. After years of development, layer-4 switching technology has become the main force in building multi-service converged networks. In a large-scale LAN, in order to reduce the dangers of a broadcast storm, a large lan must be divided into multiple small LANs based on factors such as functions or regions. This will inevitably lead to a large number of mutual access between subnets, however, the layer-4 exchange technology alone cannot achieve mutual access between subnets.

To solve this problem technically, network vendors developed a layer-3 Switch, also known as a router switch, using layer-3 exchange technology. It is a smart combination of traditional switches and routers. To put it simply, the layer-7 exchange technology that can handle layer-4 data forwarding on the network. From the hardware point of view, in the layer-3 switch, the layer-3 Routing hardware module related to the router is also inserted on the high-speed backplane/bus. In this way, the routing module can exchange data with other modules to be routed at high speed, thus breaking through the speed limit of the traditional external router interface.

A layer-3 switch is designed for IP addresses and has a simple interface type. It has a strong layer-3 packet processing capability and is much lower than a router with the same rate. It is very suitable for large-scale local area networks. The layer-3 switch technology has been quite mature today, and it has never stopped development. The development of layer-3 switching technology and layer-3 switching equipment will certainly push forward the information revolution of the whole society in a deeper level and gain an increasingly important position in the entire network.

Layer-3 switching technology with network service functions

Layer-3 switching technology unpacks each packet layer by layer and identifies information at the application layer to recognize the content. Making full use of bandwidth resources to manage applications and content on the Internet has increasingly become the focus of service providers. How to solve the problem from the transport layer to the application layer is becoming very important for the network technology dedicated to the management from the transport layer to the application layer. This is the most fundamental reason for the development of the 7th layer switching technology. To put it simply, the data exchange technology that can process the data forwarding at the network application layer is the 7th layer exchange technology. The main purpose is to improve the level of network services and turn the Internet to intelligence.

Layer-3 switching technology enables all the functions of high-level networks through application layer switches, enabling network managers to allocate network resources at a lower cost. In terms of hardware, layer-7 switches focus all functions on a dedicated application integrated circuit or ASIC. ASIC is cheaper than the CPU of traditional routers, and is usually distributed on Network Ports. It includes 50 ASIC in a single device and supports hundreds of interfaces. The new ASIC allows smart switches/routers to forward data at extremely fast speeds on all ports. layer-3 switching technology can effectively optimize data streams and achieve smart load balancing.

In the Internet, Intranet, and exclusive networks, layer-7 switches have great application aspirations. Such as e-commerce from enterprises to consumers, online customer support, personnel planning and construction, market sales automation, customer service, firewall load balancing, content filtering and bandwidth management. The exchange technology is evolving towards intelligence, from the initial 2nd-layer exchange to the 3rd-layer exchange, and has now evolved to the 7th-layer network application layer exchange. The fundamental goal is to ensure the high reliability, high performance, easy maintenance, and easy expansion of the network while reducing the cost, so as to achieve intelligent network management.