近年來無線通訊技術日趨成熟與穩定。行動隨意網路（Mobile Ad-hoc Networks， MANETs）衍生出一種新的隨意網路，兩者之間的差別在於點的移動速度更快速，導致點與點之間的連線快速的斷裂造成網路的不穩定，而這種衍生出來的網路稱作車載隨意網路（Vehicular Ad hoc Networks，VANETs），車輛之間通過裝置上的單位（OnBoard Units）這個車上單元通常裝備無線網路界面（IEEE802.11p）能連接無線網路，可以接收跟傳送訊息。訊息要有效率地繞送到目標車輛上取決於 VANET在追蹤目標位置資訊的能力。因為車輛的移動速度較快，在VANETs上定位是一項艱難的挑戰。位置管理協定（Location Service Management Protocol）被用在解決VANETs 位置資訊搜尋的問題，這些方法上有很好的潛質，但是他們仍受到許多的障礙，如信號通道 （尤其是在大型 VANETs），訊息傳送到網路黑洞等。在車輛快速地移動的模式和缺乏適當的基礎設施下，許多的位置管理協定（Location Service Management Protocol）已證明不能運作在大型的車載隨意網路，所以在車載隨意網路中位置管理是一個巨大的挑戰。在本文中，我們利用在道路上使用位置資訊點Location Information Points（固定基礎架構）的方法來提供車輛位置資訊的更新和解決車輛發出的搜尋訊息，Location Information Points以有線網路作為骨幹，能在車載隨意網路的擴展性問題上有所幫助。當網路中發生了查詢訊息，位置資訊點（LIPs）上會執行一個查找機制去搜尋目標車輛的資訊及獲得目標車輛的答覆。在目標位置未知的情況下利用泛洪搜尋協定（flooding-based protocols）在位置資訊點建構出來的重疊網路上，能讓位置查詢的過程達到最小的通訊花費同時縮小了延遲時間。

One of major concerns in VANETs are design a scalable and robust routing protocols. Messages route depends on VANETs ability to keep track of the locations of vehicle. In order to find the destination vehicle effectively, the location information of the destination must be determined. Number of Location Service Management Protocols has been proposed to deal the challenge. Though these protocols have clarify good potential, they still suffer from a number of impediments, such as signaling volume (especially in large scale VANETs), no capability to resolve network voids. Due to vehicle mobility and lack of adequate infrastructure location information of vehicle, current location management schemes had proven unable to work in large-scale network so location management is a great challenge in VANETs. In this paper we proposed a scheme that uses Location Information Points (fixed infrastructure) on the road to provide location information up-to-date and resolve lookup query of vehicle in the network which can attempt to relax the scalability issue. LIPs mark as hotspot when the vehicle density cross a constant boundary, hotspot LIPs will construct a P2P overlay network. When the query message happen in the network, a distributed LIPs lookup mechanism is proposed perform on the P2P overlay in order to get the destination reply. This scheme employ location update and lookup querying on each LIPs to achieve promise locality awareness as well as achieves minimum communication overhead.

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