In system networking, access switches, aggregation switches, and core switches are often mentioned. Generally, we call the part of the network directly facing users to connect to or access the network as the access layer, the part between the access layer and the core layer as the distribution layer or convergence layer, and the backbone of the network as the core layer . So what is a core switch? How to choose? Next, let's follow the editor of Feichang Technology to learn more about it!
1. What is a core switch
The core switch is not a type of switch, but refers to the switch at the core layer (the backbone of the network). It is located at the top of the three-tier network architecture, which is equivalent to the company's senior managers. Its main function is to quickly forward data from the aggregation layer and provide a fast and reliable network architecture through high-speed data forwarding.
The core switch is generally a layer 3 switch with network management functions. Generally speaking, core switches have a large number of ports and high bandwidth. Compared with access switches and aggregation switches, they have higher reliability, redundancy, throughput, etc. and relatively low latency. For a network of more than 100 computers, if you want to run stably and at a high speed, the core switch is essential.
2. What factors need to be considered when choosing a core switch?
The main purpose of the core layer is to provide an optimized and reliable backbone transmission structure through high-speed forwarding communication. Therefore, the core layer switch should have higher reliability, throughput and richer functions.
When choosing a core switch, consider the following aspects:
1. Port type/rate/quantity
When selecting the port type, rate, and quantity of the core switch, you should refer to the port type, rate, and quantity of the aggregation layer switch and select the corresponding one. If the budget is sufficient, you can choose a core switch with rich port types or a large number of ports. For example, if you choose a switch with 10 Gigabit uplink ports or stacking ports, you will be able to meet the expansion needs even if the network demand grows in the future.
2. Backplane bandwidth
For core switches, if you want to achieve full-duplex non-blocking, you must meet the minimum standard requirements (backplane bandwidth = number of ports * port rate * 2). The higher the backplane bandwidth, the greater the data exchange speed. The core switch The stronger the data processing capability.
3. Forwarding rate
Since the core switch carries a huge amount of network traffic, under normal circumstances, the forwarding rate of the core switch is higher than that of the access/aggregation switch [example: forwarding rate [throughput] (Mpps) = number of 10 Gigabit ports × 14.88? Mpps+number of gigabit ports×1.488 Mpps+number of hundred-megabit ports×0.1488?Mpps)].
The required forwarding rate of the core switch depends on the number of devices in the network. The required forwarding rate of the core switch can be determined by querying various traffic reports and user group analysis. Do not choose blindly, causing network bottlenecks or waste of resources.
For a three-layer switch, when the backplane bandwidth and forwarding rate both meet the minimum standard requirements, the switch is considered qualified.
4. Link aggregation
Link aggregation refers to the aggregation of multiple physical ports together to form a logical port, which can increase link bandwidth and ensure network stability. Therefore, it is better to choose a core switch with link aggregation function, which can provide sufficient bandwidth for the traffic sent by the aggregation switch to the core switch, and allow the aggregation switch to transmit traffic to the core switch as efficiently as possible.
5、VLAN & QoS
With the continuous increase of global data traffic, the voice, video, data and other traffic in the network will continue to increase. When the network traffic is large, the switch may have problems such as unreasonable control, resource allocation and even network congestion. It is not wise to just blindly increase the bandwidth of the core layer at times.
VLAN division is mainly for regional division for different applications, which can effectively control and manage the network.
QoS can give priority to real-time and important data traffic under the existing bandwidth conditions, which can effectively solve the problems of network delay and congestion. Therefore, choosing a core switch that supports VLAN division and QoS is an economical and effective way.
6. Redundant performance
The redundancy of the core switch is the guarantee of network security, so it is important to choose a core switch that can provide more redundancy as much as possible, so that when the hardware fails, it can quickly switch to avoid network paralysis, and even if the network needs in the future Growth can also meet demand.
In addition to hardware redundancy such as port redundancy (slot redundancy), module redundancy, and power redundancy, the routing redundancy of the core switch is also very important. When a certain aggregation switch connected to the core switch fails, you can rely on HSRP, VRRP protocol fast switching to achieve dual-line redundancy backup to ensure the stability of the network.
7. Security
The core layer is the backbone of the network. If it is attacked by viruses or hackers, the entire network will malfunction or even be paralyzed. Therefore, a core switch with higher security performance must be selected. such as:
The network management function can perform network management and control through ACL (Access Control List), flow control, etc.; ARP (Address Resolution Protocol) protection function can effectively reduce ARP spoofing in the network; VPN (Virtual Private Network) is used in multiple enterprises through special encrypted communication protocols Establish a secure and exclusive communication line between the intranets.
Three, more parameter considerations
In addition to considering the above parameters, the core switch also needs to look at these functions such as stacking and hot backup. These functions determine the performance, efficiency, and stability of the core switch in practical applications.
The core switch is the core and heart of the entire network. If a fatal failure occurs, the local network will be paralyzed, and the loss caused is hard to estimate. So when we choose core switches, we often see that some core switches have functions such as stacking or hot backup.
Using hot backup for core switches is an inevitable choice to improve network reliability. In the case that a core switch cannot work at all, all its functions are completely taken over by another backup router in the system until the router in question returns to normal. This is the hot backup routing protocol.
Well, the above content is about what is the core switch of Feichang Technology? How to choose a core switch? A detailed introduction to this issue, I hope it can be helpful to everyone! Feichang Technology has been specialized in the R&D, production and sales of optical transceivers, industrial switches, optical fiber transceivers, protocol converters and other industrial communication equipment for 20 years. Welcome to come to understand and exchange.
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