Comparing Three Mesh Architectures: Three competing mesh architectures are shown above. They are, from left to right:
1. 1-Radio Mesh. As shown on the left, this network uses one radio channel both to service clients and to provide the mesh backhaul. The single mesh radio, marked AH, provides both services - client access and backhaul. The comparative performance analysis to follow indicates this architecture provides the worst services of all the options , as expected- both backhaul and service compete for bandwidth.
2. Dual-Radio with a 1-Radio backhaul mesh. This configuration can also be referred to as a "1+1" network, since each node contains two radios, one to provide service to the clients, and one to create the mesh network for backhaul. The "1+1" appellation indicates that these radios are separate from each other - the radio providing service does not participate in the backhaul, and the radio participating in the backhaul does not provide service to the clients. These two radios can operate in different bands. For example, a 2.4 GHz IEEE 802.11 b/g radio can be used for service and an IEEE 802.11a (5 GHz) radio can be used exclusively for backhaul.
Competing mesh products typically fall into this category. Separating the service from the backhaul improves performance when compared with conventional ad hoc mesh networks. But since a single radio mesh is still servicing the backhaul, packets traveling toward the Internet share bandwidth at each hop along the backhaul path with other interfering mesh backhaul nodes - all-operating on the same channel. This leads to throughput degradations which are not as severe as for the single radio mesh, but which are sizeable nevertheless.
3. 3-Radio MeshDynamics MD 4350 The last architecture shown is one that provides separate backhaul and service functionality and dynamically manages channels of all of the radios so that all radios are on non-interfering channels. Performance analysis indicates that this provides the best performance of any of the methods considered here. Note that the two backhaul radios for the 3-radio configuration shown in Figure 3 are of the same type - not to be confused with 1+1 so-called dual radio meshes where one radio is typically of type A (backhaul) and the other of type B/G (service). In the 3-radio configuration, 2 radios provide up link and down link backhaul functionality, and the other radio provides service to clients.
