Geographic routing (also called georouting or position-based routing) is a routing principle that relies on geographic position information. Routing is the process of selecting paths in a network along which to send network traffic It is mainly proposed for wireless networks and based on the idea that the source sends a message to the geographic location of the destination instead of using the network address. Wireless network refers to any type of Computer network that is Wireless, and is commonly associated with a Telecommunications network whose interconnections The idea of using position information for routing was first proposed in the 1980s in the area of packet radio networks ^[1] and interconnection networks ^[2]. Geographic routing requires that each node can determine its own location and that the source is aware of the location of the destination. A node ( Latin nodus, ‘knot’ is a critical element of any Computer network. With this information a message can be routed to the destination without knowledge of the network topology or a prior route discovery.

There are various approaches, such as single-path, multi-path and flooding-based strategies (see ^[3] for a survey). A flooding algorithm is an Algorithm for distributing material to every part of a connected network. Most single-path strategies rely on two techniques: greedy forwarding and face routing. Greedy forwarding tries to bring the message closer to the destination in each step using only local information. Thus, each node forwards the message to the neighbor that is most suitable from a local point of view. The most suitable neighbor can be the one who minimizes the distance to the destination in each step (Greedy). Alternatively, one can consider another notion of progress, namely the projected distance on the source-destination-line (MFR, NFP), or the minimum angle between neighbor and destination (Compass Routing). Not all of these strategies are loop-free, i. e. a message can circulate among nodes in a certain constellation. It is known that the basic greedy strategy and MFR are loop free, while NFP and Compass Routing are not ^[4].

Greedy forwarding variants: The source node (S) has different choices to find a relay node for further forwarding a message to the destination (D). A = Nearest with Forwarding Progress (NFP), B = Most Forwarding progress within Radius (MFR), C = Compass Routing, E = Greedy

Face routing: A message is routed along the interior of the faces of the communication graph, with face changes at the edges crossing the S-D-line (red). The final routing path is shown in blue.

Greedy forwarding can lead into a dead end, where there is no neighbor closer to the destination. Then, face routing helps to recover from that situation and find a path to another node, where greedy forwarding can be resumed. A recovery strategy such as face routing is necessary to assure that a message can be delivered to the destination. The combination of greedy forwarding and face routing was first proposed in 1999 under the name GFG (Greedy-Face-Greedy) ^[5].

References

1. ^ Takagi, H. ; Kleinrock, L. (March 1984). "Optimal transmission ranges for randomly distributed packet radio terminals". IEEE Transactions on Communications 32 (3): 246–257. doi:10.1109/TCOM.1984.1096061. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
2. ^ Finn, Gregory G. (1987), Routing and Addressing Problems in Large Metropolitan-Scale Internetworks, University of Southern California, ISI/RR-87-180, <http://www.isi.edu/div7/people/finn.home/routing_and_addressing_problems_in_large_metropolitan-scale_internetworks.BW.pdf> 
3. ^ Stojmenovic, Ivan (2002). "Position based routing in ad hoc networks". IEEE Communications Magazine 40 (7): 128–134. doi:10.1109/MCOM.2002.1018018. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
4. ^ Stojmenovic, Ivan; Lin, Xu (2001). "Loop-free hybrid single-path/flooding routing algorithms with guaranteed delivery for wireless networks". IEEE Transactions on Parallel and Distributed Systems 12 (10): 023–1032. doi:10.1109/71.963415. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
5. ^ Bose, P. ; Morin, P. ; Stojmenovic, I. ; Urrutia, J. (1999). "Routing with guaranteed delivery in ad hoc wireless networks". Proc. of the 3rd international workshop on discrete algorithms and methods for mobile computing and communications (DIALM '99): 48-55. doi:10.1145/313239.313282. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  

See also

• List of ad-hoc routing protocols