How to Choose a Core Layer Switch?

NADDOD Neo Switch Specialist Jan 14, 2023

As the core backbone layer of the entire network architecture, the core layer bears the traffic transmission of the entire network, so the core layer has high requirements for core switches and must be carefully considered when selecting them. So what issues need to be considered when selecting a core switch? This article will reveal to you.

What is the Role of the Core Switch in the Network?

First, before choosing a core switch, we must fully understand what it is used for.

It is located at the top of the three-tier hierarchy model, equivalent to the top manager of the company. Its main role is to quickly forward data from the aggregation layer, providing a fast and reliable network architecture by forwarding data at high speed. Generally speaking, core switches have a high number of ports and high bandwidth. Compared with access and aggregation switches, core switches have higher reliability, redundancy, throughput, etc. and relatively lower latency.

core layer

What are the Factors to Consider When Choosing a Core Switch?

As you can see above, the core switch is the core device of the network and its performance requirements are high. Generally speaking, core switches are Layer 3 switches, which can support various network protocols such as routing protocol/ACL/load balancing and have rich functions. The following factors can be considered when selecting one.

Port Type/Rate/Number

When choosing the port type, rate and number of core switches, you should refer to the port type, rate and number of aggregation layer switches and choose the corresponding ones. Of course, if you have sufficient budget, you can choose a core switch with rich port types or a large number of ports so that you can meet the demand even if the network demand grows in the future.

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 and the greater the data processing capability of the core switch.

Forwarding Rate

Since core switches carry huge network traffic, usually, the forwarding rate of core switches is higher than both access/aggregation switches [Example: Forwarding Rate [Throughput] (Mpps) = Number of 10 Gigabit ports × 14.88 Mpps + Number of Gigabit ports × 1.488 Mpps + Number of 100 Gigabit ports × 0.1488 Mpps )]. In fact, the required forwarding rate of the core switch depends on the number of devices in the network. You can determine the required forwarding rate of the core switch by checking various traffic reports and user group analysis, and do not choose blindly to cause network bottlenecks or waste of resources.

Note: For Layer 3 switches, the switch is qualified when both the backplane bandwidth and forwarding rate meet the minimum standard requirements or higher.

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 to provide sufficient bandwidth for traffic sent from the aggregation switch to the core switch and to allow the aggregation switch to transmit traffic to the core switch as efficiently as possible.


As global data traffic continues to rise, the amount of voice, video, and data traffic in the network will continue to increase, and when the network traffic is large, the switch may not be able to reasonably control, allocate resources, or even block the network. QoS can prioritize real-time and important data traffic under the existing bandwidth conditions, which can effectively solve the network latency and blocking problems. Therefore, choosing a core switch that supports VLAN segmentation and QoS is an economical and effective way to address these issues.


The redundancy capability of a core switch is a guarantee of network security, so it is important to choose a core switch that can provide as much redundancy as possible so that the network can be quickly switched over in case of hardware failure and can meet the demand even if the network demand grows in the future. In addition to hardware redundancy such as port redundancy (slot redundancy), module redundancy, and power redundancy, it is also important to have routing redundancy in the core switch so that when one of the convergence switches connected to the core switch fails, the HSRP and VRRP protocols can be used to quickly switch to achieve redundant backup of dual lines to ensure network stability.

Note: The shorter the convergence time of the routing protocol, the better the performance of the core switch.


As the core layer is the backbone of the network, if it is attacked by viruses or hackers, the whole network will fail or even be paralyzed. Therefore it is necessary to choose a core switch with high security performance. For example.

  • Network management function can control the network through ACL (Access Control List), traffic control, etc.
  • ARP (Address Resolution Protocol) protection function can effectively reduce ARP spoofing in the network.
  • VPN (Virtual Private Network) establishes a secure and proprietary communication line between multiple corporate intranets through a special encrypted communication protocol.


With the above introduction, I believe you should understand what kind of core switch you need. You will not go wrong when choosing a core switch by referring to the above factors.