What is Mesh Topology?

What is Mesh Topology?

A mesh network is a local physical network topology in which each node is connected directly, dynamically and non-hierarchically to as many other nodes as possible and cooperate with one another to efficiently route data from/to clients.

Mesh topology is also called as fully interconnected topology. Mesh is a physical ttpe of topology. A physical topology is the way in which network is laid out physically.

Mesh Topology Diagram

Mesh Topology Diagram

Formula to Find Number of Links (Wires) in Mesh Topology

Formula:
(n(n-1))/2
In mesh topology, every device in the nework has a point to point link to every other device in the network as stated in the definition above. Thus for n devices, there will be a total of (n(n-1))/2 links. Here a link refers to a medium, usually a wire or cable used to transfer data from one node (computer or device in network) to other, but it can also be a wireless medium like microwave or satelite link. This allows direct communication between any two devices. This topology provides highest degree of fault tolerance.

What is point to point link?

A point to point link is a connection between two devices in a network such that the entire capacity of the link is reserved for transmission between those two devices. This link can be a physical cable or wireless media such as satelite link or microwaves.

Mesh Topology Examples

Here are some real life examples of mesh topology.
  1. Packet radio networks or ALOHA networks were first used in Hawaii to connect the islands. Given the bulky radios, and low data rate, the network is less useful than it was envisioned to be.
  2. In 1998–1999, a field implementation of a campus-wide wireless network using 802.11 WaveLAN 2.4 GHz wireless interface on several laptops was successfully completed.[7] Several real applications, mobility and data transmissions were made.
  3. Mesh networks were useful for the military market because of the radio capability, and because not all military missions have frequently moving nodes. The Pentagon launched the DoD JTRS program in 1997, with an ambition to use software to control radio functions - such as frequency, bandwidth, modulation and security previously baked into the hardware. This approach would allow the DoD to build a family of radios with a common software core, capable of handling functions that were previously split among separate hardware-based radios: VHF voice radios for infantry units; UHF voice radios for air-to-air and ground-to-air communications; long-range HF radios for ships and ground troops; and a wideband radio capable of transmitting data at megabit speeds across a battlefield. However, JTRS program was shut down in 2012 by the US Army because the radios made by Boeing had a 75% failure rate. Google Home, Google Wi-Fi, and Google OnHub all support Wi-Fi mesh networking.
  4. In rural Catalonia, Guifi.net was developed in 2004 as a response to the lack of broadband Internet, where commercial Internet providers weren't providing a connection or a very poor one. Nowadays with more than 30,000 nodes it is only halfway a fully connected network, but following a peer to peer agreement it remained an open, free and neutral network with extensive redundancy.
  5. In 2004, TRW Inc. engineers from Carson, California, successfully tested a multi-node mesh wireless network using 802.11a/b/g radios on several high speed laptops running Linux, with new features such as route precedence and preemption capability, adding different priorities to traffic service class during packet scheduling and routing, and quality of service. Their work concluded that data rate can be greatly enhanced using MIMO technology at the radio front end to provide multiple spatial paths.
  6. ZigBee digital radios are incorporated into some consumer appliances, including battery-powered appliances. ZigBee radios spontaneously organize a mesh network, using specific routing algorithms; transmission and reception are synchronized. This means the radios can be off much of the time, and thus conserve power. ZigBee is for low power low bandwidth application scenarios.
Reference for examples - Mesh Toplogy Examples

Mesh Topology Applications

Here are some applications of Mesh Topology.
  1. Simple ZigBee nodes can be used to control light (to turn on and off or dim them), air conditioning, heating appliances, ceiling fan etc. One or more access points are more than enough to control a whole house.
  2. Sensors used in mesh topology provide a great amount of detail about any manufacturing process. They can be used as a feedback in control systems. Wireless mesh eases the installation, maintainance and thus provide greate amount of saving in cost ($200 to $1000 per foot in some cases).
  3. Mesh Topology can also be useful in Medical field. Mesh topology makes patient monitoring more reliable and much easier, and it also helps in exapnding the range.
  4. Meshes make patient monitoring easier and more reliable, and it helps expand the range.
  5. Automatic MOnitoring
  6. Public Service Communication
  7. Miliatary Communication
  8. Security Systmes

Advantages of Mesh Topology

  • Mesh topology is robust becuase the network does not crash even if any one link becomes unusable.
  • Since data is sent along a dedicated line only the intended receiver receives it and hence it maintains the privacy of data.
  • Traffic problems are eliminated becuase of dedicated point to point link.
  • Mesh topology provides highest degree of reliability and security.
  • It is easier to identify faults and correct them in mesh topology.

Disadvantages of Mesh Topology

  • The main disadvantages is the amount of cabling required to interconnect the devices and the number of I/O ports needed at each device.
  • Mesh topology is expensive due to large number of hardware requirements (ports and cables).
  • Installation of new devices and reconnection is difficult in mesh topology.

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