A hybrid network is any computer network that uses more than one type of connecting technology or topology. For example, a home network that uses both Wi-Fi and Ethernet cables to connect computers is a hybrid. In the early years of computer networking, hybrid networks often consisted of Token Ring or Star technologies, however these were quickly antiquated by Ethernet. While textbooks often refer to these types of hybrids, they are basically extinct in 2014.
Home Network Hybrids
Although Ethernet and Wi-Fi usually use the same router in a home network, this doesn't mean that the technology behind them is identical. Both have different specifications developed by the IEEE Standards Association. Ethernet cable networks use the 802.3 standards, while Wi-Fi networks use 802.11. These standards have different rules about how data is transferred. A home WiFi Ethernet router is a hybrid device that brings these two different technologies together. Without such a hybrid device, there would be no way to connect an Ethernet-based desktop to a Wi-Fi-based tablet on the same network.
Business Network Hybrids
Business networks often rely on hybrid networks to ensure employees using different devices can access the same data, which may be stored in different locations. Since businesses seldom upgrade an entire network to the latest technology at the same time, a typical enterprise network today may include components from different eras. For example, two offices may be joined with an ATM fiber optic connection, with some people connecting to the network using Ethernet, others using Wi-Fi and home users connecting through the Internet or, more recently, 4G wireless. Technologies like Multi-Protocol Label Switching, or MPLS, allow businesses to route traffic from different technologies into the same network.
Advantages of Hybrids
The two main advantages of a hybrid network are cost-savings and accessibility. If you have an Ethernet network at home and buy a tablet, rather than replacing all of your Ethernet components with Wi-Fi, you can simply add a Wi-Fi router to your existing network. The same is true for business networks, but on a larger scale. Few businesses have the budget to replace an entire network all at once. Hybrids allow a business to bring in new networking technologies, while phasing out old technologies over the course of several years.
Disadvantages of Hybrids
The main disadvantage of hybrids are security and support costs. Each network technology introduces new security concerns. Having a router with a good firewall becomes meaningless, for example, if you add a Wi-Fi access point that hasn't been encrypted with a strong password. In business networks, supporting different types of network technologies can become expensive, since they usually need someone with expertise in each technology. Business hybrid networks are always the result of balancing the need for a fast, accessible network with the need for data security.