車用無線隨意網路（VANET）是無線隨意網路的一個特例。VANET具有不同於與其它無線隨意網路的特性，諸如高速機動性、大範圍的網路及受限制的網路拓樸等，這些特性也深深影響到在VANET上網路演算法的設計。
VANET的節點是裝備有無線網路通訊設備、全球定位系統（Global Positioning System；GPS）、電子地圖及其它用以回報相關訊息之感測器的交通工具。行動節點透過節點對節點（Vehicle-to-vehicle）或是節點對路旁基地台（Vehicle-to-Roadside）的方式來交換資料。由於其特殊環境，路由機制儼然成為VANET上的一大挑戰。
在MANET上有許多用來傳送資料的路由機制，但是它們並不是特別為VANET所設計。在VANET上，節點的快速移動使得路由協定所建立的路徑很快的失效，來源節點只傳送了一小部份資料，就必須再重新尋找路徑，造成路由請求封包充斥在網路上，形成頻寬資源的浪費和極大的路由負擔。
本論文提出一無連線式的路由機制-CSR，來源節點可透過路由探知建立一條以地理區塊為依據的路徑，在這條區塊路徑上的所有行動節點，都可以做為傳送資料的中間節點，路由資訊不會因為任一中間節點的離開而失效。這個方法可以有效降低行動節點的移動速度對路由的影響，透過跟其它演算法的模擬結果比較，CSR相較於其它的路由演算法來說，更適合用於車用無線隨意網路上。

Vehicular ad hoc network (VANET) is a special type of ad hoc network. Some characteristics, such as high mobility, wide range and constrained topology, differentiate it from other types of ad hoc networks. These properties make VANET different and significantly affect their design.
Vehicular networks consist of nodes that equipped with wireless communication devices, GPS(Global Positioning System), digital maps and optional sensors for reporting the vehicle condition. Vehicles exchange information with other vehicles as well as with access points within their radio range. Ad hoc or infrastructure wireless networks are used to propagate information. However, routing is a challenging task, due to the high dynamics of such a network.
There are many routing protocols designed to relay data in mobile ad hoc networks (MANETs), but most of them are not designed for vehicular environments. They usually require a source to use route request to establish a hop-by-hop route between itself and a destination before sending data. In VANET, fast moving nodes result in the established route expires quickly, and the source needs to reissue another route request after sending only a few data packets via the previous route. These protocols, when applied in VANET, incur a high control overhead in terms of route request packets.
In this paper, we allow a source node to discover an area path to the destination node. Data packets are relayed along this path toward the destination using different intermediate nodes at different times without having to first establish connections between them. This mechanism is essentially unaffected by node mobility. Several simulations are made to validate the performance of our mechanism and to compare with previous methods. The result shows that is suitable for a wide range of mobile applications.

[1] J. Broch, D. Johnson and D. Maltz, “The dynamic source routing protocol for mobile ad hoc networks,” IETF Internet Draft (work in progress), July 2004.
http://www.ietf.org/internet-drafts/draft-ietf-manet-dsr-10.txt
[2] C. Perkins, E. Belding-Royer and S. Das, “Ad hoc On-Demand Distance Vector (AODV) Routing,” RFC 3561, July 2003.
ftp://ftp.rfc-editor.org/in-notes/rfc3561.txt
[3] Bechler, M. Wolf, L. Storz, O. Franz, W.J. Brunswick Tech. Univ., Germany; “Efficient discovery of Internet gateways in future vehicular communication systems”, in Proc. Of IEEE VTC2003, July 2003.
[4] Alok Nandan , Shirshanka Das , Giovanni Pau , Mario Gerla , M. Y. Sanadidi, Co-operative Downloading in Vehicular Ad-Hoc Wireless Networks, Proceedings of the Second Annual Conference on Wireless On-demand Network Systems and Services (WONS'05), p.32-41, January 19-21, 2005
[5] R. Sherwood, R. Braud and B. Bhattacharjee, Slurpie:A Co-operative Bulk Data Transfer Protocol, In Proc.of IEEE INFOCOM 2004.
[6] S. Das, A. Nandan, G. Pau, M.Y. Sanadidi, and M. Gerla, “SPAWN: A Swarming Protocol for vehicular Ad-hoc Wireless Networks,” First ACM Workshop on Vehicular Ad Hoc Networks (VANET 2004)
[7] Marco Fiore, Claudio Casetti, Carla-Fabiana Chiasserini, “On-demand content delivery in vehicular wireless networks,” Proceedings of the 8th ACM international symposium on Modeling, analysis and simulation of wireless and mobile systems (MSWiM 2005)
[8] J. Ott and D. Kutscher, Drive-thru Internet: IEEE 802.11b for Automobile Users, In Proc. of IEEE INFOCOM 2004.
[9] H. Hartenstein, B. Bochow, A. Ebner, M. Lott, M. Radimirsch, and D. Vollmer. Position-Aware Ad Hoc Wireless Networks for Inter-Vehicle Communications: the Fleetnet Project. In Proc. ACM Mobihoc’01, 2001.
[10] Dedicated Short Range Communications (DSRC) Home. http://www.leearmstrong.com/DSRC/DSRCHomeset.htm.
[11] C. Lochert, H. Hartenstein, J. Tian, D. Herrmann, H. Fler, and M. Mauve, “Routing strategy for vehicular ad hoc networks in city environments,” Proc. of IEEE Intelligent Vehicles Symposium (IV2003)
[12] B. Karp and H. T. Kung, “GPSR: Greedy perimeter stateless routing for wireless network,” In Proc. of MobiCom 2000. page 243-254, Boston, MA, USA, Aug. 2000.
[13] Ai H. Ho, Yao H. Ho, and Kien A. Hua, “A Connectionless Approach to Mobile Ad Hoc Networks in Street Environments,” Proc. of IEEE Intelligent Vehicles Symposium (IV 2005), Nevada , USA . June 2005, pp. 575- 582
[14] Y. H. Ho, A. H. Ho, K. A. Hua, and G. L. Hamza-Lup, “A connectionless approach to mobile ad hoc networks,” Proc. Of The Ninth IEEE Symposium on Computers and Communications. Alexandria, Egypt, June, 2004.
[15] Xiang Zeng, Rajive Bagrodia, Mario Gerla GloMoSim: a library for parallel simulation of large-scale wireless network, Proceedings of the twelfth workshop on Parallel and distributed simulation, May 1998, Banff, Alberta, Canada.
[16] Y.-C. Tseng, S.-Y. Ni, Y.-S. Chen, and J.-P. Sheu, “The broadcast storm problem in a mobile ad hoc network,” Wireless Networks, vol. 8, pp. 153–167, March-May 2002.
[17] Saha, A. K., and Johnson, D. B. Modeling mobility for vehicular ad-hoc networks. In Proc. Of ACM VANET (2004).
[18] Korkmaz, G., Ekici, E.,  Ozguner, F., and  Ozguner, U.Urban multi-hop broadcast protocol for inter-vehicle communication systems. In Proc. of ACM VANET (2004).
[19] Hao Wu, Richard Fujimoto, Randall Guensler and Michael Hunter , “MDDV: A Mobility-Centric Data Dissemination Algorithm for Vehicular Networks ,” In Proc. of ACM VANET (2004).
[20] Rahul Mangharam, Jacob J. Meyers, Dr. Ragunathan Rajkumar, Dr. Daniel D. Stancil, Jayendra S. Parikh, Dr. Hariharan Krishnan, Christopher Kellum, “A Multi-hop Mobile Networking Test-bed for Telematics,” 2004 SAE International.