What Does Wireless Mesh Network (WMN) Mean?
A wireless mesh network is any wireless network where data is transmitted using mesh networking. That is, where nodes don’t just send and receive data, but also serve as a relay for other nodes and each node collaborates in propagating data on the network.
A wireless mesh network can be thought of as a collection of nodes where each mesh node is also a router. Compare this to a WiFi access point where service can be provided only within reach of the signal and when it is turned off, the connection is gone. Mesh nodes work differently by rerouting data to another hop which it is connected to, bypassing the empty area where a node might be off.
The concept of mesh networking can be applied to both physical and wireless networking, but it’s much more commmon for wireless networks given the cabling costs that would be required to implement as a physical topology.
A key difference here is that mesh nodes work in a cooperative gain scheme where the more nodes that are active, the greater the bandwidth available Consider this analogy in traditional networking: when cars (data) coming from a wide road comes to a small bridge they all have to slow down to wait in line. To increase the number of cars going through, you need to make a bigger bridge (add bandwidth) which is then wasted in times of less traffic. In mesh networking, imagine people coming to a river, where in order to continue each person drops a rock to make a foot bridge. The more people that needs to pass, the more rocks are thrown in. But if there are fewer users, then only a few rocks are needed. In other words, the bandwidth scales automatically based on the number of users.
Characteristics of wireless mesh networks
- Dynamic self-configuration and self-organization
- Fault tolerance and robustness
- Integration and interoperability
How do wireless mesh networks work?
Wireless mesh networks work through nodes mesh clients and gateways
- Mesh nodes are WAP devices with multiple radio systems. Nodes act as mesh routers and endpoints. Firmware enables them to share data between other nodes in the network.
- Mesh clients are wireless devices, such as laptops, mobile phones and tablet computers.
Each node in a WMN has at least one, but often multiple, paths to other nodes, creating multiple routes of information for pairs of users. This makes the network more resilient, and in the event of a WAP or connection failure, information can still access other nodes.
The network topology of a wireless mesh network may be full or partial mesh. A full mesh network means every node communicates with every other node. In a partial mesh topology, nodes only communicate with nearby nodes. When data is transmitted between two nodes that do not communicate with each other, data hops from one node to the next until it reaches the client. The nodes are programmed to use adaptive routing algorithms to constantly determine the optimal route between nodes for data transmission.
In a wireless mesh network, each node receives data from one node while forwarding data to the next node. The resulting network between connected devices is often called a mesh cloud. Having more nodes increases the range of the network that the mesh client devices can connect to for internet. Only one node will need to act as a gateway to and from the internet for connectivity.
Mesh Network Pros
For the right system, mesh networks are the best option. They have three major advantages over other networks:
Mesh networks don’t require additional routers. Instead, each node acts as router instead. This means you can quickly and easily change the size of the network.
For example, you can easily add a bunch of technology to a conference room for a short period of time. Laptops, printers and more can be moved into the room and will automatically connect to the network.
Even non-technical applications can benefit from this type of network. For example, a mesh network for lighting can be added to just about any office. This allows you to simply add light sources as you like, with the ability to control the entire network from anywhere.
Resistant to Problems
Each node in a mesh network both receives and translates information. This provides a lot of redundancy, which helps keep the network running even if a problem occurs. If one node goes down, the network can use other nodes to complete the mesh.
Easy to Add Range
Adding range to a mesh network is usually not a problem. You simply connect nodes to gateways, which allow messages to pass through to the rest of the network. Plus, mesh networks can self-optimize and find the fastest route to deliver a message.
Mesh Network Cons
Mesh networks aren’t always the right choice. There are three disadvantages you’ll want to be aware of before committing to this type of network:
Increased Workload for Each Node
Each node in a mesh network has a lot of responsibility. Aside from sending messages, the node also must act like a router. Every node added to the mesh network also makes the system more complex.
Nodes will need to track messages from five or 10 neighbor nodes. Every message a node has to pass along contains an exponential increase in the amount of data it also has to handle. Increasing the range of the system can add a variety of unwanted complications due to the related increased in the data load.
Initial Network Setup can be Complicated
Once a mesh network is up and running, adding nodes is pretty simple. But implementing a mesh network from the ground up is usually much more complicated and time-consuming than setting up something more traditional.
Latency issues will dictate where you need to place nodes. You might need to add dedicated nodes solely for the purposes for forwarding messages. But this can be a logistical issue. You might have to add equipment throughout your location just so messages can be routed properly and quickly.
Benefits or advantages of Wireless Mesh
Following are the benefits or advantages of Wireless Mesh:
➨If there is fault at any of the wireless end nodes or devices or stations, the entire network does not shut down. This means error or fault at one node does not affect other nodes in the network. Only the region covered by particular faulty nodes will be affected. The service will be restored by another healthy node automatically or manually.
➨The nodes or stations are self organizing and requires minimal manual settings for operational. Centralized management is not required. Hence it does not require periodic maintenance unlike star based system.
➨Wireless mesh network overcomes limitations of wired mesh network in LAN application such as requirement of 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.
➨The wireless mesh network offers excellent reliability and freedom for mobile users of the system with minimum configurations.
Drawbacks or disadvantages of Wireless Mesh
Following are the drawbacks or disadvantages of Wireless Mesh:
➨There are no central entity called base station or hub station in the wireless mesh network architecture. Hence routing and resource management processes are complex compare to cellular network or any other star topology based wireless network system.
➨The nodes are complex as they need to have transmit/receive functionalities as well as house routing algorithms.
➨It is difficult to install and manage as there is no central place from where entire network can be monitored and controlled. As a result troubleshooting is poor.
➨As the nodes house complex functionalities, they are expensive.
➨It is more secure as communication starts and ends at user terminals.
Conclusion: In summary advantages of Wireless Mesh network are improvement in fault tolerance without the need of centralized management and so on. The disadvantages of Wireless Mesh are difficult to install and manage in addition to costly end devices for subscribers/users of the network.
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