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Autonomous Mobile Mesh Networks and their Design Changes. Curtis Oelmann. Ad hoc wireless networks. Set of mobile nodes that are: S elf-organizing Self-healing Survivable Instantaneously available all without having infrastructure. Multi-hop mesh networks.
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Autonomous Mobile Mesh Networks and their Design Changes Curtis Oelmann
Ad hoc wireless networks • Set of mobile nodes that are: • Self-organizing • Self-healing • Survivable • Instantaneously available • all without having infrastructure
Multi-hop mesh networks • Has two or more hops to any one node. • These networks should also have multiple paths to get to a particular node. • The data being transmitted will “hop” to each node until the data reaches its particular destination. • Must be able to update the current layout of the mesh network incase a node leaves the area.
Mobile Mesh Networks • Autonomous • Multi-hop • Highly dynamic • Human-centric • Broadband mesh networks
Categorization of mesh networks Page 240
Public Safety Services • Work on the 4.94 - 4.990GHz band • Car accidents and first responders • Surveillance-youtube.com
Disaster relief • Hurricane Katrina • If there had been a mesh network, nodes from inside New Orleans would have been able to pinpoint where people were. • With surveillance cameras mounted on telephone poles, the data would have been able to go from hop to hop transmitting data back to the first responders and police. • The people we seen looting from stores would have been prosecuted because the police would have had video
Defense/Military operations • Easily torn down and set up • On the move support • Voice over ip
Consumer/Home Networking • New Blu-ray Dvd players • Surround sound • Wireless routers are limited, with multi-hop devices, the range is much greater.
Transportation Applications • I-pass
Physical Radio Channels • Commercial-off-the –shelf (COTS) • Work on the 802.11 standard • Allows access to many types of devices today • PDA • Laptops • Cell phones • Other home appliances
Medium of Mesh networks • Can work with access points connected to the internet or company intranet. • Task Group S • OSI layer 2 mesh • Called ‘Extended Service Set (ESS) Mesh Networking’ • Autonomous systems can stand alone, so the discovery process is needed to find other nodes in the area that are also supporting this type of access.
Routing and Multicasting • We need : • A way to discover if a new node has entered the group • A way to update the group is a node goes down or leaves the group • A way to minimize the number of hops data takes to reach the destination. • A way to maximize the bandwidth being used • A way to minimize power consumption by the nodes
Choosing a Route • On-demand • The routes are established when a packet is sent. When the receiver gets a packet, they look at the route it took, and get the layout topology of other nodes in the group • Proactive • The nodes are continuously updating the topology by sending small packets • High overhead
Route Reestablishment • Class exercise
Security • Wireless eavesdropping • Wal-Mart Example • DOS • ‘Node a’ sending countless packets to ‘node b’ could block access to other node, ‘node c’ from being able to use ‘node b’ to get to ‘node d’
IP Addressing • Needs have a large set of address space IPv6 • IPv4 only give 4 billion addresses • It is feasible for two computers to have the same address. • IPv6 would give 2128 or about 3.4×1038 • Helps With DAD (duplicate address detection systems)
Roaming • Node should be able to: • Roam from one network to another • Connections should be seamless • Should not lose connections to data that may be critical • Acquire new IP addresses instantaneously whether another autonomous mesh or a fixed mesh
Applications • Real time video • Voice over Multi-hop mesh • Instant Multimedia messaging • Resource tracking • Affinity group