Wireless Mesh Networks: Advantages and Disadvantages

This page explores the advantages and disadvantages of Wireless Mesh Networks, along with a basic introduction to their functionality.

What is a Wireless Mesh Network?

Introduction:

Network topologies come in various forms, including star, tree, and mesh configurations, as illustrated in Figure 1.

A wireless mesh network consists of wireless nodes interconnected in a mesh topology. Due to its structure, it is also known as a wireless ad-hoc network. These networks operate without relying on a pre-existing infrastructure. They are also described as self-organizing networks or multi-hop networks. In a mesh network, two nodes communicate either directly or indirectly through other nodes along a determined path or route.

Figure 1: Network Topology Types

To better understand wireless mesh networks, let’s examine two examples: Zigbee and VSAT.

Example #1: Zigbee Mesh Network

As shown in Figure 2, a Zigbee mesh network comprises a Zigbee coordinator (ZC), Zigbee routers (ZR), and Zigbee end nodes connected in a mesh configuration. The system uses the Ad hoc On-demand Distance Vector (AODV) routing protocol to route packets from source to destination. There is no single network element to manage the entire network.

Zigbee nodes and routers individually take responsibility to route the packet. One zigbee coordinator is needed initially to start the network. Each node contains a unique and permanent 64-bit address. Furthermore, Zigbee requires that data to be transmitted is sent to the 16-bit network address of the destination node or device. Hence it is important to know the 16-bit address of the destination before transmission of the data.

Example #2: VSAT Mesh Network

Figure 3 shows a VSAT mesh network. In a mesh configuration, a hub station isn’t necessary for VSATs to communicate. Two VSATs can communicate directly with or without using a satellite, depending on their antenna arrangement. In contrast, star configurations require a hub station for VSAT communications. Similarly, in cellular systems, mobile subscribers communicate via a Base Station (or eNB).

Figure 2: VSAT Network Architecture Topologies

Benefits (Advantages) of Wireless Mesh Networks

Here are the key benefits of using a wireless mesh network:

• Fault Tolerance: If a wireless node or device fails, the entire network doesn’t shut down. The error or fault at one node does not affect other nodes in the network. Only the area covered by the faulty node will be affected. The service will be restored by another healthy node automatically or manually.

• Self-Organizing: Nodes are self-organizing and require minimal manual configuration for operation.

• Decentralized Management: Centralized management is not required. Hence, it doesn’t require periodic maintenance, unlike star-based systems.

• Reduced Cabling: Wireless mesh networks overcome the limitations of wired mesh networks in LAN applications, such as the need for more cables and NIC cards. For example, to interface 8 computers, each computers require NIC cards and 28 cables are needed to connect each one with the other seven computers.

• Reliability and Mobility: Wireless mesh networks offer excellent reliability and freedom for mobile users with minimal configurations.

Drawbacks (Disadvantages) of Wireless Mesh Networks

While offering numerous benefits, wireless mesh networks also have some drawbacks:

• Complex Routing and Resource Management: There is no central entity such as a base station or hub station. Therefore, routing and resource management are more complex compared to cellular networks or other star topology-based wireless systems.

• Node Complexity: Nodes are complex, as they must have transmit/receive functionalities and house routing algorithms.

• Difficult Installation and Management: Installation and management can be challenging without a central point for monitoring and control, leading to poorer troubleshooting.

• Expensive Nodes: As the nodes house complex functionalities, they are expensive.

• Security: It is more secure as communication starts and ends at user terminals.

Conclusion

In summary, the advantages of wireless mesh networks include improved fault tolerance without the need for centralized management. However, they can be difficult to install and manage, and the end devices can be costly for subscribers/users.