Here's Why Your Network Might Need a Layer 3 Switch GA S REGULAR Menu Lifewire Tech for Humans Newsletter! Search Close GO Internet, Networking, & Security > Home Networking 269 269 people found this article helpful

Here's Why Your Network Might Need a Layer 3 Switch

A great tool for network efficiency, usually implemented in corporate settings

By Bradley Mitchell Bradley Mitchell Writer Massachusetts Institute of Technology University of Illinois An MIT graduate who brings years of technical experience to articles on SEO, computers, and wireless networking. lifewire's editorial guidelines Updated on July 16, 2021 Reviewed by Chris Selph Reviewed by Chris Selph Chris Selph is a CompTIA-certified technology and vocational IT teacher. He also serves as network & server administrator and performs computer maintenance and repair for numerous clients. lifewire's editorial guidelines Tweet Share Email Tweet Share Email

In This Article

Expand Jump to a Section What Is a Layer 3 Switch Purpose How It Works VLANs Challenges Network switches operate at Layer 2 (data link) of the OSI model, while network routers operate at Layer 3 (network). This distinction leads to confusion over the definition and purpose of a Layer 3 switch, also called a multilayer switch.

What Is a Layer 3 Switch

A Layer 3 switch is a specialized hardware device used in network routing. Layer 3 switches technically have a lot in common with typical routers, and not only in physical appearance. Both can support the same routing protocols, inspect incoming packets, and make dynamic routing decisions based on the source and destination addresses inside. One of the main advantages of a Layer 3 switch over a router is in the way routing decisions are performed. Layer 3 switches are less likely to experience network latency since packets don't have to take additional steps through a router. Pixabay

Purpose of Layer 3 Switches

Layer 3 switches were conceived as a way to improve network routing performance on large local area networks like corporate intranets. The key difference between Layer 3 switches and routers lies in the hardware internals. The hardware inside a Layer 3 switch blends that of typical switches and routers, replacing some of a router's software logic with integrated circuit hardware to offer better performance for local networks. Additionally, having been designed for use on intranets, a Layer 3 switch will typically not possess the WAN ports and wide area network features that a standard router offers. These switches are most commonly used to support routing between virtual LANs. Benefits of Layer 3 switches for VLANs include: Reduces the amount of broadcast traffic.Simplified security management.Improved fault isolation.

How Layer 3 Switches Work

A typical switch dynamically routes traffic between its individual physical ports according to the physical addresses—the MAC addresses—of connected devices. Layer 3 switches use this capability when managing traffic within a LAN. They also expand on this traffic-handling process by using IP address information to make routing decisions when managing traffic between LANs. By contrast, Layer 4 switches also factor TCP or UDP port numbers.

Using a Layer 3 Switch With VLANs

Each virtual LAN must be entered and port-mapped on the switch. Routing parameters for each VLAN interface must also be specified. Some Layer 3 switches implement DHCP support that can be used to automatically assign IP addresses to devices within a VLAN. Alternatively, an outside DHCP server can be used, or static IP addresses configured separately. Most home networks don't use virtual LANs.

Challenges With Layer 3 Switches

Layer 3 switches cost more than ordinary switches but less than routers. Configuring and administering these switches and VLANs also requires additional effort. The applications of Layer 3 switches are limited to intranet environments with a sufficiently large scale of device subnets and traffic. Home networks usually have no use for these devices. Lacking WAN functionality, Layer 3 switches are not a replacement for routers. The naming of these switches comes from concepts in the OSI model, where layer 3 is known as the Network Layer. However, this theoretical model does not do well distinguishing practical differences between industry products. The naming has caused much confusion in the marketplace. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit More from Lifewire What Is a Switch? Computer Networking What Is a Dynamic IP Address? One Home Network Sharing Two Internet Connections Can Two Routers Be Used on the Same Home Network? Cisco Default Password List (Updated October 2022) Private IP Addresses: Everything You Need to Know NETGEAR Default Password List (Updated October 2022) How to Connect Two Routers on a Home Network What Is an IP Address? What Is a Hub in a Computer Network? How to Find the Default IP Address of a Belkin Router How to Use an IP Address to Find a MAC Address How Is a Router Different From a Switch? How to Set Up Port Forwarding What Is a Router and How Does It Work? What Is a Virtual LAN (VLAN) and What Can It Do? Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies