Layer 2 and Layer 3 Switches: Features and Applications Discussed


Industrial network switches form the basis of several high speed data networks. These switches are used to connect different devices in a network, and thus are one of the important requirements. The network communications are described in the Open System Interconnect (OSI) model. This model operates on seven layers: Application Layer, Presentation Layer, Session Layer, Transport Layer, Network Layer, Data Link Layer, and Physical Layer. The layer 2 managed switch operate on the data link layer and the layer 3 switch on the network layer. Among these, layer 2 switches are one of the key requirements for any high speed network. As the converged networks grow in size, and density of data networks increases, the demand for layer 3 switches increases, too. This article explores these two switch types, their typical features, and their applications in modern data networks.

A Brief Introduction to Layer 2 and Layer 3 Switches

The following pointers will help you understand the basic difference between layer 2 and layer 3 switches.
  • Layer 2:

    These switches act as bridges, where they interconnect networks on its media access control (MAC) sublayer. Layer 2 switches build tables for transferring the frames among networks. Ethernet switches are the most common types of layer 2 switches known to us. The devices connected in the Ethernet network possess a hardcoded MAC address. These MAC addresses generally do not change.
  • Layer 3:

    These switches follow the Internet Protocol or IP. Like layer 2, the devices connected to layer 3 switches are identified by their individual IP addresses. Unlike layer 2 switches where the MAC addresses do not change, the IP addresses of the devices change regularly because they are assigned dynamically. Router is the most common example of this type of switches, which is usually connected to devices with differing IPs. In short, these switches route the data frames from the host to the client by following the IP addresses of the client device.
In recent years, layer 2 managed switches and layer 3 managed switches have gained immense popularity. Of these, the layer 2 managed switches are used in applications wherein the switch forwards the traffic between the network hosts located in the same subnet. For instance, it may forward the traffic between the client PC and the server in the same network. This transmission is made on the basis of the MAC table. Layer 3 switches are used if the client PC and the server are located in different subnets. The network transmission decision is made based on the map of the IP network present in its routing table.

Features of Layer 2 Switches and Layer 3 Switches

Here are some differentiating features of both the network layers.

Layer 2 Switches

  • Layer 2 switches can transport data easily and rapidly between the client and the host in LAN networks.
  • These switches learn the MAC address of the destination node from the address table maintained in the switch. The data frames from the source to the destination node are arranged on the basis of this MAC address.
  • The switch splits highly dense and bulky LAN networks into various small VLAN networks.
  • These multiple VLANs make switching easier in a large LAN network as there are no physical connections involved.

Layer 3 Switches

  • These switches perform static and dynamic routing while transferring data between multiple VLANs.
  • The dynamic routing enables these switches to optimize their packet routing.
  • Multiple paths are offered to the switch in real time enabling them to deliver different data packets. The switch can choose the most effective path for delivering these data packets.
  • Most layer 3 switches are equipped with features such as loopback detection, 802.1x authentication, and ARP inspection, which enables secure data transfer. Thus, layer 3 switches are becoming a popular choice for applications where data security is highly important.
  • These network switches take advantage of VLAN traffic tagging, or subnetting to implement QoS classifications. Against this, the layer 2 switches are known to perform manual switch port configuration for this implementation. 

Applications of Layer 2 and Layer 3 Switches


Layer 2 Switches

  • Layer 2 smart switches are generally employed for improving internal communications within an organization.
  • These switches are used to configure the hosts on the same LAN. This reduces the need for Internet connection, which is otherwise used for such configurations.

Layer 3 Switches

  • These switches are commonly used in the fast growing campuses, organizations, as well as data centers, where high density networking is involved.
  • When used in combination with layer 2 switches, these switches can accommodate any number of users, and help reduce the need for increasing bandwidth or adding extra layer 3 switches or making any additional investments. This flexibility makes them an ideal choice for the fast-growing enterprises, where high speed networks are implemented. 
  • They can support bandwidth-hungry end-user applications and resources.
  • Layer 3 switches are used in several high density WANs comprising overloaded routers. In such networks, each individual switch is configured with a main router. This configuration enables it to manage the VLAN routing at the local level and optimizes the work efficiency of router enabling it to perform long distance data transmission.
  • Owing to its features, the layer 3 switches can single handedly manage the traffic controlling and routing in LANs utilizing bandwidth hungry devices.

Conclusion

As the difference between layer 2 switches and layer 3 switches is now clear, it is important to invest in quality switches to support high speed data networks in your organization. Today, you can see several manufacturers specializing in layer 2 managed switches, layer 2 smart switches, and layer 3 switches. However, not all may serve your purpose. VERSITRON is one of the leading manufacturers of layer 2 and layer 3 network switches. You can visit: www. versitron.com to know more about these switches and other fiber optic devices provided by the company.