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According to the Cisco support forums, Ad-Hoc means peer-to-peer while mesh means bridge-to-bridge or router-to-router, meaning in a mesh every node has the capability to route.

So would mesh networks be subparts or subcases of ad-hoc networks?

m4573r
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caub
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  • An *Ad-Hoc-Network* normally is when the Peers (minimum: 2) create a network with each other w/o some other routing infrastructure. E.g. a cross-cable. In a wireless one you can normally spare the cable (;)), however the network cards need to support such a connection. – hakre Sep 29 '12 at 13:38
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    They are different, orthogonal attributes. An "ad-hoc" network is one that self-organizes, vs being planned. A "mesh" network is one where there is essentially many-to-many connectivity with no central hub. A network can be one without the other, or it can be both. – Daniel R Hicks Sep 29 '12 at 13:45
  • @'hakre so you mean ad-hoc would be in a lower layer than mesh that have all the network layer alreay there. @DanielRHicks mesh networks selforganizes no, (reactively or proactively)? I don't see your point – caub Sep 29 '12 at 14:06
  • I'd say that @DanielRHicks coined it quite good. – hakre Sep 29 '12 at 14:08
  • These two Wikipedia pages do a very good work of explaining the details: [Wireless Mesh Network](http://en.wikipedia.org/wiki/Wireless_mesh_network) & [Wireless Ad-Hoc Network](http://en.wikipedia.org/wiki/Wireless_ad-hoc_network). – nik Sep 29 '12 at 14:30
  • ^ "A wireless mesh network can be seen as a special type of wireless ad-hoc network" – caub Sep 29 '12 at 14:31
  • You need to understand that the terms have meanings outside of 802.11 or whatever. A specific standard may apply a narrower definition to a generic term, or may slightly broaden the meaning. – Daniel R Hicks Sep 30 '12 at 16:47
  • of course @DanielRHicks Ad-Hoc is commonly used, and mesh is used for many other fields, my question was really to know if we could call mesh networks, or tree-based networks.. Ad-hoc networks in a more general way – caub Oct 01 '12 at 17:01
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    No, as I said, the two terms describe two totally different characteristics of a network. If you're talking about a *specific* network standard (or group of standards), you may be able assert that "if A them B", but in the general case neither one implies the other. – Daniel R Hicks Oct 02 '12 at 16:26

3 Answers3

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In wireless networking, Ad-Hoc is one of the modes of operation for an 802.11 radio. It happens at OSI layer 1, the physical layer, and it basically means that all devices can communicate directly to any other device that is within radio range. Normally, in Infrastructure mode, wireless devices can only communicate with a central Access Point or Router and that device is responsible for re-transmitting packets from one client device to another client device (even if they are right next to each other). Ad-Hoc networks get rid of the middle-man that is the AP, however they don't have any inherent capability for multi-hop. That means, if device A can reach device B, and device B can reach device C, but A cannot reach C, then A and C cannot communicate because B will not re-transmit any packets.

Mesh Networking, also know as Mesh Routing happens at OSI layer 3, the network layer. Mesh Routing allows each device on a network (also called nodes) to act as a router and re-transmit packets on behalf of any other devices. Mesh Routing provide the multi-hop facility that Ad-Hoc mode lacks. By combining Ad-Hoc mode at layer 1 and Mesh Routing at layer 3 we can create wireless mesh networks purely between client devices without any need for centralized Access Points or Routers.

P2P or Peer-to-Peer simply means that clients talk directly to each other without the use of a central server. Both Ad-Hoc and Mesh Routing can be described as P2P as they are both instances of clients-to-client communication, just at different layers of the OSI model.

Sitwon
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  • just if I could give more up votes .. perfect answer – McLan Jul 15 '14 at 13:42
  • I vote up for you Rania ;P. Thanks again for the great explanation Sitwon! – Melroy van den Berg Dec 04 '14 at 19:24
  • It's a good answer, but mesh networks aren't *always* layer-3. In fact, many enterprise mesh networks are layer-2 but most FOSS meshes are L3. – qasdfdsaq Jul 09 '15 at 11:05
  • Sure, that's possible, but not typical in wireless networks (which my answer explicitly assumes). It's also possible to implement mesh networking at higher OSI layers. Common examples of L4 meshes would be TOR, I2P, and CJDNS (though I understand it can also work at lower layers, it was originally and primarily a L4 mesh). – Sitwon Jul 10 '15 at 14:15
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I think the distinction between them is quite difficult since an adhoc network could grow into a mesh network.

Ad hoc : simply infrastructure-less type of network(no dedicate Access points or predetemined infrastructure) that is meant to serve any purpose, and they are built spontaneously. these type of networks are simple and could be set easily. common applications can be seen in simple sensor networks.

mesh: infrastructure-based type of networks. could be seen in wireless or wired networks in the sense that they are permanent type of networks. they are more structured than Ad-Hoc networks. they might be hierarchical . common applications can be seen in variety of applications;home monitoring and control, military applications(communications and reconnaissance),environmental monitoring, and so on.

Salah Amean
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...In addition A MANET is the infrastructureless type of a Wireless Mesh Network. The clients, all the nodes share the same functions with respect to the network operation, and there is no node that is in charge of authentication or security services. Clients do not have multi-hop capability.

In WMN, there could be infrastructure type where packets are being routed using not only hop metrics but also other metrics for path selection. And some WMNs operate in hybrid such that the network exploits the nodes redundancy. WMN uses self-organizing network functionality to overcome some problems that are inherent to wireless networks such as tradeoff between distance and transfer rates, or other problems such as congestion, configuration, and installations cost.

pensebien
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