3 General characteristics Communications network made up of radio nodes organized in a mesh topologyForm of a wireless ad hoc networkWMN do not require centralized access points to mediate the wireless connectionWMN Multi-hop feature – increases the coverage area and link robustness of existing Wi-Fi’s; ( if the correspondent nodes are not in the wireless transmission range of each other)Dramatic increase in link quality just by shortening the distance between the nodes
4 General characteristics (cont.) Dynamically self-organized and self-configured systems (one node can automatically establish and maintain the mesh connectivity)The integration of WMNs with other networks such as Internet, IEEE , , , sensor networks etc can be accomplishedWMNs offer multiple redundant communications paths throughout the network and adaptiveWireless nodes: mobile or fixed
5 TYPE of nodes Mesh Router contains additional routing functions to support mesh networking.usually equipped with multiple wireless interfaces built on either the same or different wireless access technologiesimproves the flexibility of mesh networkingMesh Clientscan also work as routers since they also have necessary functions for mesh networking.gateway and bridge functions do not exist in these nodes.usually have only one wireless interface as in Laptop/desktop PC, pocket PC, PDA, IP phone, RFID reader, etc.
6 WMN ArchitectureBased on the functionality of the nodes the architecture of WMNs can be classified into:Infrastructure mesh Architecture,Client mesh Architecture andHybrid mesh Architecture
7 Infrastructure meshIn infrastructure mesh architecture, the mesh routers collectively provide a wireless backbone infrastructure. Client node is passive in mesh infrastructure
8 Infrastructure mesh (CONT.) Via Ethernet links conventional clients with Ethernet interfaces can be connected to mesh routers.If the conventional clients have the same radio technologies as the mesh routers then they can communicate directly with the mesh routersIf different radio technologies are used then the clients communicate with their base station that have Ethernet connections to mesh routers
9 Client meshClient meshing provides peer-to-peer networks among client devices. Here no such mesh router is required. Client will act both like a mesh router by relaying the packets and like an end user.
10 Hybrid architecture Mesh router provide the backbone of such network. With the help of network functionalities such as routing and forwarding of data packets, clients can actively participate in the creation of the mesh.
11 STandardIEEE s is the most relevant emerging standards for WMN technologyEfforts are underway in several IEEE working groups, like , , , and , to define mesh standards.
16 Protocol layersSome of the factors that affect the capacity and performance of WMNsnetwork architecture,network topology,traffic pattern,network node density,number of channels used for each node,transmission power level, andnode mobility.In order to develop the protocols we need to clearly understand the relationship between the above factors and the capacity of WMNs.
17 Routing protocol General Ad-hoc routing protocol: Pro-activeRe-activeHybridCategories of routing protocol in WMN:Ad-hoc based (LQSR, SrcRR, MR-LQSR)Controlled flooding (LOLS, MMRP, OLSR)Traffic Aware (AODV-ST)Opportunistic (ExOR, ROMER)
18 questionWireless Mesh Network is a radical network form of the ever evolving wireless network. The Mobile Ad-hoc network is also a form of the wireless network. Compare and contrast the wireless mesh network and the Mobile Ad- hoc network that are the categories in the multi-hop wireless network !
19 Comparison wmn and manet There are various factors which can differentiate wireless mesh network from Ad-hoc Network. The major differences between these two types of network are the network topology and mobility of nodeNetwork topology: Ad- hoc network are called as the infrastructure less network with a highly dynamic topology where as WMN have a relatively static network topologyMobility of relay nodes: In Ad-hoc network the relay nodes have a higher degree of mobility i.e. relay nodes aren't fixed whereas in WMN's the degree of mobility of relay node is much lower than in Ad-hoc netowrks.
20 Comparison wmn and manet (cont.) Deployment: Some planning is required to deploy the WMNs whereas Ad- hoc network is easy to deploy.Infrastructure requirement: Ad-hoc network is infrastructure less whereas WMN has partial or fully fixed infrastructure.Energy constraints: In Ad-hoc network energy constraints is high whereas it is low in the WMNs.