What Is A Wireless Mesh Network?
By Justin Pender on 5th Aug 2014
First of all, why write about wireless mesh networking? Well, without blowing our trumpet too vigorously, it’s something we know a great deal about having designed and deployed many outdoor wireless mesh solutions across a variety of outdoor working environments.
Why should you care? Well, there are many reasons that a mesh network might be a better option for your business when compared to more traditional network set-ups. Mesh topology is particularly desirable where network cabling may be difficult, expensive or impractical, due to the nature of the landscape, or when leased cabling options exceed budgetary allowances.
A Wireless Mesh Network offers a sophisticated solution to achieving network connectivity across large areas, without the requirement for many meters of Ethernet cabling to each point (or ‘node’ – see the jargon buster below). Mesh Wi-Fi networks achieve this as only one node needs to have a physical Ethernet connection to the wired network (and then potentially onwards to the Internet).
Once a node has a physical connection to the wired network it will share its connection wirelessly with other nodes within its radio cell, and then these nodes will then share their connection with other nodes within their radio cells…and so the process continues exponentially (depending on the size of the area to be covered).
*It should be noted that, despite the lack of Ethernet connection, a power supply to each node is still required.
Are you confused yet? Hopefully this diagram from our mesh network deployment at Berthon Boats' Lymington Marina can help a little...
Wireless Mesh Networking - jargon buster
As is often the case, wireless networking often throws up the odd curveball with regards to particular terminologies, so here is a quick ‘jargon buster’ to hopefully remedy any confusion…
Core Network/backbone – Provides paths to pass traffic between different networks ie different subnets can talk to each other.
- Back hauling - Visualize this as a 4 wheel drive car, the core network will be the engine, the backhaul links will be the axles, the end points, or nodes will be the wheels and the individual links back to the core will be the tyres.
- Points/Nodes - A ‘Mesh Point’ is an access point that has no Ethernet cable connected to its Ethernet socket. The access point uses its radio to connect to the ‘Mesh Portal’ either directly or via neighbouring mesh points that relays data back to a portal, node.
- Portals - A ‘Mesh Portal’ is an access point which has an Ethernet cable connected to its Ethernet socket. This in turn is connect to the wired network.
- 2.4GHz & 5GHz – these radio frequency bands operate on different frequency bands
- 2.4GHz - operate on 3 non over lapping channels typically 1, 6 and 11
- 5GHz - has 3 channel bands lower 36 – 48 (4) channels, middle 52 – 64 (4) channels and upper 100-140 (11) channels.
Full and partial Mesh Networks
A Full Mesh Network can consist of dozens, or even hundreds, of mesh nodes which communicate with each other across the area of wireless coverage. Essentially, these mesh nodes function in the same way as a wireless router - the router directs traffic from the client to the end destination and then back to the client - some or all nodes may act as a router and some or all nodes may also be an end point.
Offering network redundancy, a full mesh network is the most reliable option for mission critical deployments. In the unlikely event that a point or node becomes unresponsive, the remaining networks components can still operate and communicate with one or more nodes within their radio cell, thus ‘self-healing’ through seeking new paths for data transfer and allowing data to travel across the network in the fewest possible ‘hops’.
A Partial Mesh Network functions according to the same principles; each access point communicates with the others in a ‘chain-like’ sequence, if the chain breaks the client will then seek to associate and authenticate with the closest access point in order to transfer data back to the core - illustrated in the diagrams below.
Wireless Mesh Networking at Berthon Marina
The wireless network at Berthon Marina consists of twelve Aruba Instant AP104 access points deployed in a fell mesh configuration. Should one of these access points cease communication within the mesh network, traffic will be re-routed to avoid the broken link.
In this particular configuration, four of the access points (AP01, AP02, AP07 & AP10) are deployed as ‘Mesh Portals’ and have a wired Ethernet connection back to the core, whilst the remaining eight access points are acting as ‘Mesh Points’ or ‘Mesh Nodes’.
The marina has two mesh points installed on each pontoon (pontoon B through to E) which link back to the landside mesh portals utilising their 802.11a radios to form the back haul link. This particular network has been designed to provide wireless coverage across the marina’s berths with an RF signal level of no less than -65dBm and a signal to noise ratio (SNR) greater than 20 dB at 2.4 GHz (802.11g).
If you are considering a wireless mesh solution for your business or organisation and would like some advice on outdoor WiFi networking, please get in touch with our technical team firstname.lastname@example.org or call 01929556 553.
If you are planning to deploy an enterprise-grade wireless network or are experiencing problems with a existing setup, please feel free to contact Ensign Communications for a chat with our technical team.
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