What Is a Node in a Computer Network?

A node is any physical device within a network of other tools that’s able to send, receive, or forward information. A personal computer is the most common node. It's called the computer node or internet node.

Modems, switches, hubs, bridges, servers, and printers are also nodes, as are other devices that connect over Wi-Fi or Ethernet. For example, a network connecting three computers and one printer, along with two more wireless devices, has six total nodes.

Nodes within a computer network must have some form of identification, like an IP address or MAC address, for other network devices to recognize them. A node without this information, or one that's offline, no longer functions as a node.

What Does a Network Node Do?

Network nodes are the physical pieces that make up a network. They usually include any device that both receives and then communicates information. But they might receive and store the data, relay the information elsewhere, or create and send data instead.

For example, a computer node might back up files online or send an email, but it can also stream videos and download other files. A network printer can receive print requests from other devices on the network, while a scanner can send images back to the computer. A router determines which data goes to which devices that request file downloads within a system, but it can also send requests out to the public internet.

Other Types of Nodes

In a fiber-based cable TV network, nodes are the homes or businesses that connect to the same fiber optic receiver.

Another example of a node is a device that provides intelligent network service within a cellular network, like a base station controller (BSC) or Gateway GPRS Support Node (GGSN). In other words, the mobile node is what provides the software controls behind the equipment, like the structure with antennas that transmit signals to all the devices within a network.

A supernode is a node within a peer-to-peer network that functions not only as a regular node but also as a proxy server and the device that relays information to other users within the P2P system. Because of this, supernodes require more CPU and bandwidth than regular nodes.

What Is the End-Node Problem?

The term "end node problem” refers to the security risk that comes with users connecting their computers or other devices to a sensitive network, either physically (like at work) or through the cloud (from anywhere), while at the same time using that same device to perform unsecured activities.

Some examples include an end-user who takes their work laptop home but then checks their email on an unsecured network like at a coffee shop or a user who connects their personal computer or phone to the company’s Wi-Fi network.

One of the most significant risks to a corporate network is a compromised personal device that someone uses on that network. The problem is pretty clear: mixing a potentially unsecured network and a business network that likely contains sensitive data.

The end user’s device might be malware-infested with things like keyloggers or file transfer programs that extract sensitive information or move malware to the private network once it logs in.

VPNs and two-factor authentication can help fix this problem. So can special bootable client software that can only use specific remote access programs.

However, another method is to educate users on how to secure their devices correctly. Personal laptops can use an antivirus program to keep their files protected from malware, and smartphones can use a similar antimalware app to catch viruses and other threats before they cause any harm.

Other Node Meanings

"Node" also describes a computer file in a tree data structure. Much like a real tree where the branches hold their leaves, the folders within a data structure contain records. The files are called leaves or leaf nodes.

The word "node" also appears in node.js, which is a JavaScript runtime environment that executes server-side JavaScript code. The "js" there doesn't refer to the JS file extension used with JavaScript files; it's just the name of the tool.