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Roofnet was an experimental 802.11b/g mesh network developed by the Computer Science and Artificial Intelligence Laboratory at the Massachusetts Institute of Technology (MIT). Research included link-level measurements of 802.11, finding high-throughput routes in the face of lossy links, link adaptation, and developing new protocols which take advantage of radio’s unique properties (ExOR). The software developed for this project is available free as open source.
The routing protocol is called SrcRR. There are two broadcasts used with the protocol. The first is periodic broadcasts used to determine a metric called ETX. These public broadcasts measure the probability that a packet between two nodes in radio contact reaches its destination. The second broadcast type is used to build up routing tables. A node 0 will broadcast that it wants to find a route to D. Then each node that receives the broadcast will add its id to the route and forward the packet. When node D receives a packet, it will reply back along the route that was found for that packet. Then node 0 can use this information to determine the best route using the ETX metrics and the route information returned from its query.
One media access and forwarding protocol tested with RoofNet was ExOR. ExOR simulates some advantages of multicasted data networks by using conventional 802.11 digital radios operated in broadcast modes.
The source radio uses routing data to establish a list of radios that could help reach the destination radio. The list is ordered so that radios closer to the destination are nearer to the head of the list. The destination is at the head of the list. The list is compactly stored in each packet.
Each packet also includes a list that shows the progress of each packet through the list of radios. This list has one entry per packet. Each entry is the number of radio that is closest to the destination and has retransmitted that packet. The source initially sets this list all to the source radio's number.
Then, the source broadcasts a batch of packets. Radios not on a packet's list discard the packet.
Radios on the list save the packet. They update their list of radios transmitting each packet. But they wait a calibrated time before they retransmit any packet. The time is less if they are closer to the destination. The time is a probabilistic estimate of the time to retransmit the packets that will be retransmitted by radios closer to the destination.
If a radio receives a packet transmitted from a radio that is closer to the destination, the farther radio throws away that packet, and never retransmits it. It also updates its list of packet progress.
As they work backwards toward the source, the retransmissions propagate the batch of packets' progress information back to the source radio.
At the end, a few packets of each batch sent by the source may never reach the destination. It sends these on by the most reliable route, using conventional routing.
Roofnet's technology formed the basis for Meraki, a mesh networking startup founded by members of MIT's Parallel and Distributed Operating Systems group. [1] Meraki was acquired by Cisco Systems in 2012. [2]
Internetwork Packet Exchange (IPX) is the network layer protocol in the IPX/SPX protocol suite. IPX is derived from Xerox Network Systems' IDP. It also has the ability to act as a transport layer protocol.
A network switch is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device.
Network topology is the arrangement of the elements of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and control radio networks, industrial fieldbusses and computer networks.
Wireless community networks or wireless community projects or simply community networks, are non-centralized, self-managed and collaborative networks organized in a grassroots fashion by communities, non-governmental organizations and cooperatives in order to provide a viable alternative to municipal wireless networks for consumers.
In the IEEE 802 reference model of computer networking, the logical link control (LLC) data communication protocol layer is the upper sublayer of the data link layer of the seven-layer OSI model. The LLC sublayer acts as an interface between the medium access control (MAC) sublayer and the network layer.
Link-state routing protocols are one of the two main classes of routing protocols used in packet switching networks for computer communications, the others being distance-vector routing protocols. Examples of link-state routing protocols include Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS).
A wireless mesh network (WMN) is a communications network made up of radio nodes organized in a mesh topology. It can also be a form of wireless ad hoc network.
The Optimized Link State Routing Protocol (OLSR) is an IP routing protocol optimized for mobile ad hoc networks, which can also be used on other wireless ad hoc networks. OLSR is a proactive link-state routing protocol, which uses hello and topology control (TC) messages to discover and then disseminate link state information throughout the mobile ad hoc network. Individual nodes use this topology information to compute next hop destinations for all nodes in the network using shortest hop forwarding paths.
Ad hoc On-Demand Distance Vector (AODV) Routing is a routing protocol for mobile ad hoc networks (MANETs) and other wireless ad hoc networks. It was jointly developed by Charles Perkins and Elizabeth Royer and was first published in the ACM 2nd IEEE Workshop on Mobile Computing Systems and Applications in February 1999.
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A computer network is a set of computers sharing resources located on or provided by network nodes. Computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are made up of telecommunication network technologies based on physically wired, optical, and wireless radio-frequency methods that may be arranged in a variety of network topologies.
A wireless ad hoc network (WANET) or mobile ad hoc network (MANET) is a decentralized type of wireless network. The network is ad hoc because it does not rely on a pre-existing infrastructure, such as routers or wireless access points. Instead, each node participates in routing by forwarding data for other nodes. The determination of which nodes forward data is made dynamically on the basis of network connectivity and the routing algorithm in use.
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The ETX metric, or expected transmission count, is a measure of the quality of a path between two nodes in a wireless packet data network. It is widely utilized in mesh networking algorithms.
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Scalable Source Routing (SSR) is a routing protocol for unstructured networks such as mobile ad hoc networks, mesh networks, or sensor networks. It combines source routing with routing along a virtual ring, and is based on the idea of "pushing Chord into the underlay".
IEEE 802.11s is a wireless local area network (WLAN) standard and an IEEE 802.11 amendment for mesh networking, defining how wireless devices can interconnect to create a wireless LAN mesh network, which may be used for relatively fixed topologies and wireless ad hoc networks. The IEEE 802.11s task group drew upon volunteers from university and industry to provide specifications and possible design solutions for wireless mesh networking. As a standard, the document was iterated and revised many times prior to finalization.
The Collection Tree Protocol (CTP) is a routing protocol for wireless sensor networks. It is used for transferring data from one or more sensors to one or more root nodes.
Deterministic Networking (DetNet) is an effort by the IETF DetNet Working Group to study implementation of deterministic data paths for real-time applications with extremely low data loss rates, packet delay variation (jitter), and bounded latency, such as audio and video streaming, industrial automation, and vehicle control.