Difference between Layer 3 Switch and Two-layer Switch

Layer 3 switch PC vs. Layer 2 switch PC

The Layer 2 switch PC operates at the second layer (data link layer) of the OSI model, hence its name. A layer 3 switch PC is a switch with some router functions, and its most important purpose is to speed up data exchange within a large LAN. Its routing function serves this purpose and can achieve one-time routing and multiple forwarding. So, what is the difference between a two-layer switch and a layer 3 switch?

Differences between Layer 3 switch PC and Layer 2 switch PC

• Different work layers: The Layer 2 switch PC works at the data link layer, while the layer 3 switch PC works at the network layer. The layer 3 switch not only achieves high-speed forwarding of data packets, but also achieves the optimal network performance based on different network situations.

• Different principles: A Layer 2 switch PC follows a specific process when it receives a data packet from a port. First, it reads the source MAC address in the packet, then it reads the destination MAC address. It then checks its address table to find the corresponding port for the destination MAC address. If there is a port entry in the table that matches the destination MAC address, the switch directly forwards the data packet to that port. This allows for efficient data forwarding within the local network.

  In contrast, the principle of a layer 3 switch is relatively straightforward, which is to perform routing and multiple switchings once. In simple terms, the layer 3 switch performs the first routing from the source to the destination and then switches this data to the second layer. Therefore, whether it is from the destination to the source or from the source to the destination, rapid exchange can be achieved.

• Different functions: The Layer 2 switch pc is based on MAC address access, only does data forwarding, and cannot configure IP addresses. The layer 3 switch pc combines layer-2 switching technology with layer-3 forwarding capabilities. In other words, the layer 3 switch pc adds routing functions based on the layer 2 switch pc, and can configure IP addresses of different VLANs. VLANs can communicate with each other through three-layer routing.
  

• Different applications: The layer 2 switch pc is mainly used in the network access layer and aggregation layer, while the layer 3 switch pc is mainly used in the network core layer. However, there are also a few cases where a layer 3 switch pc is used in the aggregation layer.
  

• Different supported protocols: The layer 2 switch pc supports physical and data link layer protocols, such as Ethernet switches and two-layer switches, which are similar to the functions of a HUB. The layer 3 switch pc supports physical, data link, and network layer protocols.