Analyze the absolute advantages of layer-3 Switch Technology

The wide application of layer-3 switch technology enables dedicated bandwidth between network sites, avoiding unnecessary Collision Detection and error re-transmission, greatly improving work efficiency. What is the difference between it and other routing devices? What is the function? With these questions, let's take a look at its advantages. In order to adapt to the challenges brought by the deepening of network applications, in the past 20 years, the Network has developed rapidly in the speed and network segments.

In terms of speed, it provides users with higher bandwidth: the speed of the LAN has increased from 10 Mbit/s to 100 Mbit/s. Currently, Gigabit Ethernet technology has been widely used. At the same time, FDDI and ATM technologies provide users with more options to increase the network speed. There has also been a qualitative breakthrough in the network segment: it has evolved from an earlier LAN with shared media to the current one. 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 first-layer interface and the second-layer exchange technology that are directly oriented to users have obtained satisfactory answers. However, as the core of the network, the router technology that acts as the interconnection between networks has no qualitative breakthrough. Traditional routers are software-based and have complex protocols. Compared with lan speed, their data transmission efficiency is low.

At the same time, it serves as the hub for interconnection between network segments (subnets and virtual networks), which makes traditional router technologies face severe challenges. With the rapid development of Internet/Intranet and the wide application of the B/S (Browser/Server) computing model, cross-region and cross-network business is growing rapidly, the industry and users are deeply aware of the bottleneck effect of traditional routers in the network.

It is imperative to improve the traditional routing technology. In this case, a new routing technology came into being. This is the layer-3 switching technology: it is a router because it can operate on the layer-3 of the network protocol, it is a type of routing that understands a device and can act as a route decision. It is a switch because it is extremely fast and almost achieves the second-layer switching speed.

Evolution of Network Integration Technology

Network technology continues to evolve and evolve with the needs of applications. In the early 1980s s, when the first generation of LAN technology began to be applied to internal enterprise networking, its applications were mainly limited to host connection, file sharing, and print sharing, the 10 Mbit/s channel shared by multiple users can meet the requirements.

As the network grows, more and more online users are available. In particular, users' applications have switched to customers/servers, high-traffic applications, Intranet Web access, and real-time audio/video services. At that time, the network system was no longer competent, as shown in the following figure: HUB is a communication device based on shared media, and it is a first-level device. User Data Collision Detection and error re-transmission greatly reduce transmission efficiency. The bridge can be used to minimize network segments and reduce collision domains to optimize LAN performance. It is a second-level device that can identify MAC addresses and intelligently forward information between local networks.

However, it is a device that is transparent to the upper-layer (layer-3 switch technology or above) protocols and cannot effectively prevent broadcast storms. Vrouters play a key role in subnet interconnection, security control, and broadcast storm restrictions. However, their complex algorithms and low data throughput make them the network bottleneck.

Aware of the above problems, the industry started from the HUB and bridge infrastructure that directly targets users and can form independent LAN devices, and revolutionizes network technology, the biggest change is to replace the HUB with LAN switches in the next generation of network system integration to improve network performance.

A large number of LAN switches were introduced in the network system integration mode in early 1990s. LAN switches are Layer 2 network devices. They can understand Layer 2 network protocols, such as MAC addresses. Layer-3 switch technology constantly collects data during operations to create its own address table. This table is quite simple. It mainly indicates the port on which a MAC address is found. Therefore, when the switch receives a data packet, it checks the target MAC address of the packet, check your address table to determine the port from which the data is sent. Instead of the HUB, any sender data will appear on all the ports of the HUB (whether or not required for you ).

The introduction of layer-3 switch technology enables exclusive bandwidth between network sites, eliminating unnecessary Collision Detection and error re-transmission, and improving transmission efficiency, in a vswitch, several independent and independent communication processes can be maintained in parallel. In the exchange network environment, user information is transmitted only between the source node and the target node, and other nodes are invisible. However, when a node sends a broadcast or multi-object broadcast on the Internet, or a node sends a MAC address packet that the switch does not know, all nodes on the vswitch will receive this broadcast message. The entire exchange environment constitutes a large broadcast domain.

Industry insiders use a new term Flat Network to describe this environment: multiple switches Interconnect (stacked) to form a large LAN, but cannot effectively divide subnets. "Peer To Peer" is a fast and effective exchange on the second layer. However, broadcast storms can compromise network efficiency. Vswitches are much faster and cheaper than vrouters. However, layer-2 switching also exposes vulnerabilities: it cannot effectively solve broadcast storms, inter-network interconnection, and security control. Therefore, the virtual network technology on the vswitch is generated. In fact, a virtual network is a broadcast domain. In order to avoid the broadcast storm caused by large-scale layer-3 switch technology broadcast, it can be further divided into multiple virtual networks. In a virtual network, information sent by a workstation can only be sent to other sites with the same virtual network number. Other Virtual Network members cannot receive the information or broadcast frames.