We’ll explain the most important things you need to know about network topology, why mesh technology is unique, and why it’s becoming so popular.
What Does “Topology” Mean?
Topology refers to how things are arranged in relation to each other. For example, an area’s topological map isn’t used much for detailed navigation, but it shows the “big picture” arrangement of points of interest. In the context of computer science and networks, topology refers to how the elements of a network are linked together. It describes which nodes on a network can communicate directly before going through another node.
Other Types of Network Topology
There are five general types of network topology, each with its advantages and disadvantages. Linear Bus Topology networks have all nodes connected to a single cable. This cable is known as a “backbone” connection, with a “terminator” at each end of this main cable. Data only flows in one direction at a time, known as a “half-duplex” system. This is a simple network setup that doesn’t require much cabling. However, the weakness in a bus topology is that the entire network stops functioning if anything goes wrong with the backbone cable. It’s also hard to pinpoint which device on the network might be causing issues, making troubleshooting time-consuming. Ring Topology networks don’t have a single cable with terminators on each end. Instead, all the nodes are arranged in a circle, with every node always having another node on both sides. Unlike linear bus topology networks, ring topology networks operate in a full-duplex mode so that data can be sent and received simultaneously. Like bus topology, any fault in the cable brings the whole network down. Star Topology networks are the most common type of home network today. Here, all of the nodes in the network have a direct connection to a central device. This can be a network switch, hub, or router. All network traffic flows through this primary device. One disadvantage of this topology is the potential for network congestion and, of course, the hub device as a single point of failure. It also requires much more cabling than the above network topologies in a wired network. However, in most home networks, this is a non-issue since most devices are connected to the wireless router using Wi-Fi, with Ethernet reserved for a handful of devices. Tree Topology (aka Expanded Star Topology, aka Hierarchical Topology) takes the idea of a star topology network and expands it into a tree-like architecture. For example, your home router is the center of your star topology, but it’s a node on a bigger star with a local router, which is a node on an even bigger star. The different star topology networks are also connected to a backbone cable, so the “trunk” of the tree topology is a linear bus network, and the “branches” are star topology networks. Keep these general network designs in mind as we unpack mesh topology.
Mesh Topology
A Mesh Topology network offers a direct connection between any two nodes. Unlike bus or ring topologies, network traffic doesn’t have to pass through every node on the network to reach its destination. Nor does network traffic have to pass through a central hub as it does with a star topology. Any two nodes can communicate privately, with no chance that anyone else on the network can eavesdrop. That’s true of full mesh networks, but there are two types of mesh network topology, so let’s briefly unpack the first.
Full Mesh Topology Versus Partial Mesh Topology
There are two types of mesh topology. In Full Mesh networks, every node on the network has a point-to-point connection to every other node. This means that no matter where two nodes are located on the network, there’s a direct wired or wireless connection between them. This requires the most complex wiring with the number of connections rapidly with every node added. A Partial Mesh network has the same basic philosophy in its design that nodes on the network connect directly to other nodes, but not every node is connected to every other node. Every node is connected to at least one other node, and often more than one, but the partial mesh isn’t nearly as complex.
The Advantages of Mesh Topology
The main advantage of a full mesh network is redundant connections. Even if a direct connection between any number of nodes fails, they can always get through by routing through another network node, even if it isn’t as fast. Even better, it’s easy to pinpoint where the fault is by design, so fixing things is relatively easy. In that sense, full mesh networks are like the internet as a whole, where at least one viable route for data transmission is always available, even if large network segments go down. Partial mesh networks offer less redundancy, although the network designers can concentrate on giving the most critical nodes the most connections, balancing redundancy, cost, and complexity. Besides being redundant, mesh networks have a significant advantage regarding network performance since nodes can all send and receive data simultaneously, choosing the most efficient routes through the network. This means reliable, low latency networking performance perfect for IoT (Internet of Things) setups in smart homes. Mesh networks have exceptional privacy since data moves between network devices in full mesh systems. Finally, mesh networks have excellent scalability without negatively affecting network performance or bandwidth. A mesh network can grow organically over time by adding new nodes and hooking them into the nearest nodes (partial mesh) or all other notes (full mesh).
The Disadvantages of Mesh Topology
The two main disadvantages of mesh topology are cost and complexity. Partial mesh setups help balance these issues, but a full-mesh, wired network is like a spider’s web of connections. Mesh networks have higher power consumption than other network types. That’s because all nodes must be active and turned on to provide routing paths for data. There’s also a significant maintenance burden since individual nodes that develop issues for any reason must be fixed or replaced to maintain network performance.
Wireless Mesh Networks in the Home
Local Area Networks (LANs) used in the home have traditionally been star topology networks. All devices connect to a central router, whether by Wi-Fi or Ethernet. The need for internet connectivity in the entire home is growing with the rise of smart devices and home appliances. A centralized device can cause performance bottlenecks and limit the reach of both wired connections and wireless signals without using repeaters or extenders. Repeaters and extenders come with complex configurations and worse network performance, so they aren’t the ideal solution for whole-home networking. Mesh network routers in the home are an example of partial mesh networks or perhaps a type of hybrid topology. Not all nodes are connected to every node. Instead, the primary node connects to the WAN (Wide Area Network), which is another way of referring to the greater internet beyond your home network. That primary node is connected directly to devices like laptops and smartphones, but it also sets up dedicated wireless connections to other mesh network units. Every mesh router connects to the following mesh unit with the best connection speed and reliability. That connection can be over Wi-Fi or through Ethernet “backhaul,” where a high-speed cable connects some mesh router units. As devices move around the home, they are seamlessly handed off between mesh units as each one relays the path to the internet. Client nodes such as smartphones are not used as part of the mesh. No traffic is routed through one client device directly to another. All traffic passes to the nearest mesh router node. If you want to expand the network to improve performance or coverage, add more mesh units. As you can see, “mesh” wireless networks for home use don’t quite match the template of an actual mesh network. Instead, it’s more like having several star-topology networks linked together by a set of dedicated mesh sub-connections. Still, this is the most advanced and seamless home network solution. One we can recommend to anyone, assuming your budget will stretch to this new technology.
