Link aggregation is a computer networking feature that combines or aggregates multiple network or internet connections to utilize the full speed of all of the network connections. Link aggregation is traditionally a corporate network feature as companies are more likely to have multiple internet connections for redundancy than home users.
Network redundancy is designed to protect companies against the risk of its internet connection going down. If one connection drops the second redundant or back-up connection can be used instead. In standard usage, however, there is little reason to leave the backup internet connection unused. Link aggregation allows you to combine both internet connections seamlessly, increasing the available internet bandwidth.
For home users, link aggregation is generally not a useful feature, as most people don’t have more than one home broadband connection. The main exception for this is mobile devices such as a mobile phone, that have a cellular data connection. On these devices, link aggregation can combine the internet connection of both the mobile data network and a Wi-Fi connection to provide the best possible speeds – in fact, recent generation phones all support this feature by default.
Link aggregation doesn’t necessarily have to be used for internet connections; any network connection can be aggregated together allowing faster access to internal resources such as file servers not just the Internet.
More than two links can be aggregated together, although the hardware support for more than two network connections is generally limited outside of enterprise-grade networking hardware.
Windows by default supports link aggregation, allowing users with multiple internet connections to share internet load across all of their network connections.
When using an aggregated network connection, you may experience an interruption of your data speed if one of your internet connections drops.
This effect should be similar to what happens when you’re using the internet on your phone, walk out of the Wi-Fi range of your house, and switch over to mobile data. A small amount of data will be lost which will be re-transmitted over the remaining network or networks that still have an internet connection. In this scenario, you may notice a reduction in internet speed and some hitches in real-time data connections such as voice or video calls, but they should automatically resolve themselves very quickly and automatically.