Why do we need a Layer 3 switch? Seven indicators for selecting a Layer 3 switch in a monitoring system

Recently, a friend asked about the application of layer 3 switches in monitoring systems. Today, I will introduce it. The monitoring system consists of five parts: video acquisition, transmission, control, display, and storage. The switch is mainly responsible for data transmission. Generally, a small monitoring LAN system with less than 50 channels can use a layer 2 switch with a router. A medium-sized monitoring system with about 100 channels requires the efficient routing performance of a layer 3 switch.

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The role of switches at each layer

• Access layer: The access layer directly connects user computers and enables various network resources to access the network. It provides users with the ability to access application systems in the local network segment, mainly to solve the needs of mutual access between adjacent users, and provides sufficient bandwidth for these visits.
• Aggregation layer: The "intermediary" between the network access layer and the core layer. It aggregates the workstations before they access the core layer to reduce the load on the core layer equipment. The aggregation layer has multiple functions such as policy implementation, security, workgroup access, routing between virtual LANs, source address or destination address, etc.
• Core layer: The main purpose is to provide fast and reliable backbone data exchange through high-speed forwarding communications.

Why use a layer 3 switch?

(1) If a three-layer core switch is not used, all monitoring is in one subnet, which may cause a broadcast storm, paralyzing the network and poor security.

(2) The three-layer core switch implements the IP routing function by using a hardware switching mechanism. Its optimized routing software improves the efficiency of the routing process and solves the speed problem of traditional router software routing. As mentioned above, the three-layer core switch also has an important role in ensuring the connection of subnets with high speed and efficiency.

For monitoring of about 100 channels, in order to reduce the number of computers in the same network, VLAN division is inevitable, so many IP subnets need to be further divided to prevent the generation of broadcast storms. The tasks between subnets also need to rely on a three-layer switch.

(3) Layer 3 switches are scalable. Layer 3 switches are scalable and can connect multiple subnets. Subnets only establish logical connections with the Layer 3 switch module, and do not require traditional routers to add ports. If additional network equipment is needed, various expansion module interfaces are reserved, and the equipment can be expanded directly without changing the original network layout and equipment, thus protecting the original investment.

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High security is also an important aspect of the three-layer switch. The three-layer switch is at the core of the network layer and is definitely the target of network hacker attacks. In terms of software, a highly reliable firewall can block unidentified data packets. In addition, an access list can be set to restrict internal users from accessing certain special IP addresses.

The above mentioned several reasons for choosing a three-layer switch in the monitoring system. Now let's introduce seven indicators for selecting a three-layer switch when setting up a monitoring system in an enterprise.

Generally speaking, a medium-sized LAN monitoring system only needs to place a three-layer switch in the backbone network and a two-layer switch in the access layer. But facing the numerous switches on the market, how can we choose a three-layer switch with good quality and stable performance? The editor suggests that although there are many switches on the market, when buying, if it can meet the following main indicators, it can be confirmed that it is an excellent three-layer switch.

• First, stable performance. Layer 3 switches are mostly used in the backbone and aggregation layers, and they play an important role in the network. If their performance is unstable, they will cause great damage. Therefore, only Layer 3 switches with stable performance can ensure the uninterrupted operation of the user network. This can be concluded by testing multiple indicators such as throughput, latency, frame loss rate, back-to-back function, address table depth, line end blocking, many-to-one function, etc. Among them, the back-to-back switching capability directly affects the overall packet forwarding and data flow processing capabilities.
• Second, it is safe and reliable. This includes both software and hardware. As the core equipment of the network, the three-layer switch is naturally the focus of hacker attacks. Therefore, firewalls should be equipped, especially for some key departments. Redundancy should be considered in hardware: whether there are important redundant components, such as backup power supply, management module, redundant ports, etc. This is especially important for users such as telecommunications and finance who have high requirements for security and reliability. The three-layer switch of broadband operators should also support some special protocols such as 802.1x to achieve authentication.
• Third, it is full-featured. Multicast, QoS, port trunking, 802.1d Spanning Tree, and support for routing protocols such as RIP and OSPF are very important for a Layer 3 switch. If it is not available, it will be difficult to meet user needs.
• Fourth, it is easy to expand. The product should not only meet the current needs, but also meet the needs in the future, so as to give users a value-added space and provide guarantee for future network expansion.
• Fifth, good service. Users buy not only equipment, but also a commitment to the company's network. You should examine whether the manufacturer can quickly respond to users' questions, whether it can quickly replace products and accessories, and whether it can provide users with customized functions and services.
• Sixth, it is good usability. In terms of appearance, you should check whether the indicator light settings are reasonable, whether there are fault indicators and flow indicators, etc.; whether there is a power switch; whether there are accessories for rack installation; the manual should be clear and detailed, preferably in Chinese, and the network management software should also have a Chinese interface.
• Seventh, it is a good price-performance ratio. You should consider your own funds and needs, and choose a product that is stable, easy to use, and sufficient. Don't pursue high performance and full functions one-sidedly.

In general, the selection of a three-layer switch should not only consider the quality of the product, but also the service of the manufacturer. In a sense, especially when high-tech enterprises face more risks in their development, manufacturers do not sell products, but time. Products from manufacturers with strong strength not only mean good quality of the product itself, but also the manufacturer's after-sales service and future product development and upgrades are fully guaranteed. There are more than 80 network equipment manufacturers in the Chinese market. In the long run, the market will be concentrated on a few powerful manufacturers. Therefore, when users purchase equipment, choosing a leading manufacturer such as Cisco will be the first choice for building an efficient and reliable network and protecting corporate investment.