In system networking, access switches, aggregation switches, and core switches are often mentioned. Usually, we refer to the part of the network that directly connects or accesses users as the access layer, the part located between the access layer and the core layer as the distribution layer or aggregation layer, and the backbone of the network as the core layer. So what is a core switch? How should we choose?
1、 What is a core switch
Core switches are not a type of switch, but refer to switches placed at the core layer (network backbone). It is located at the top layer of the three-layer network architecture, equivalent to the senior management of the company, and its main function is to quickly forward data from the aggregation layer, providing a fast and reliable network architecture through high-speed forwarding of data.
Core switches are generally layer 3 switches with network management functions. Generally speaking, core switches have a large number of ports and high bandwidth. Compared to access switches and aggregation switches, they have higher reliability, redundancy, throughput, and relatively lower latency. A network with over 100 computers requires a core switch for stable and high-speed operation.
2、 What factors should 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, core layer switches should have higher reliability, throughput, and richer functions.
When choosing a core switch, the following aspects should be considered:
- Port type/speed/quantity
When selecting the port type, speed, and quantity of the core switch, one should refer to the port type, speed, and quantity of the aggregation layer switch and choose the corresponding one. If the budget is sufficient, you can choose a core switch with a wide variety of port types or a large number of ports. For example, choosing a switch with 10 Gigabit uplink ports or stacked ports can meet expansion needs even in the future when network demand grows.
- Backplane bandwidth
For core switches, in order to achieve full duplex non blocking, they must meet the minimum standard requirements (backplane bandwidth=number of ports * port rate * 2). The higher the backplane bandwidth, the faster the data exchange speed, and the stronger the data processing capability of the core switch.
- Forwarding rate
Due to the large network traffic carried by core switches, their forwarding rate is usually higher than that of access/aggregation switches? How many Mpps+Gigabit ports x 1.488 Mpps+100Mbps ports x 0.1488? Mpps ）】。
The forwarding rate required by the core switch depends on the number of devices in the network. The forwarding rate required by the core switch can be determined by querying various traffic reports and analyzing user groups. Do not blindly choose, which may cause network bottlenecks or resource waste.
For a three-layer switch, it is considered qualified when both the backplane bandwidth and forwarding rate meet the minimum standard requirements.
- Link aggregation
Link aggregation refers to aggregating multiple physical ports together to form a logical port, which can increase the number of links
