車輛間的通訊的已經越來越普及，智慧型車輛系統可以幫助使用者更容易得到資訊。隨著使用者的需求增加和製造車輛廠商的投資驅使車輛之間的溝通更加容易實現。在這個領域中有很多的應用和服務正慢慢增加中，除此之外，也有一部份的路由已經被開發出來但卻不適合這個移動性高的網路。因此我們試著找出一個適合這個系統的路由方案。 為了要改善系統效能跟減少delay時間，我們選擇地理位置相關的路由協定LAR來減少flooding封包。LAR是一種reactive的路由協定且它使用地理位置來減少flooding的overhead，然而LAR並沒有把壅塞的情況考慮進去，因為這是一個減少delay的重要因素。所以我們提出一個新的方案，叫做Traffic Aware Location Aided Routing (TALAR) 來改善壅塞的情況。我們也考量使用AP的優點、像較大的傳輸範圍以及固定的傳輸範圍，來更有效的找出路由路徑。 我們使用QUALNET simulation來評量，結果顯示delay時間有明顯改善，所以認為他的確有助於這個高速智慧型車輛的系統。 / The growth of inter-vehicle communication is exploding. An intelligent vehicular system (IVS) can help users in vehicles to get information more conveniently. The requirements from users and investment of car manufacture drive vehicle communication to become reality. Many applications and services are in demand over this new technology. Some architecture and routing methods have been developed, however, they may not suitable for IVS due to its high mobility and variable environment. Therefore, we try to find out a good routing solution for this system. In order to improve the performance and decrease delay, here we select geographic routing LAR (Location-Aided Routing) to reduce the flooding overhead. LAR is a reactive routing and it utilizes location information to reduce the flooding overhead. However, it seems not to take congestion into account which is an important factor for reducing delay. We propose a new scheme, called Traffic Aware Location Aided Routing (TALAR) to improve the congestion situation. We also use the AP’s advantageous properties such as extended transmission range and stability to help routing paths getting more efficient. We evaluate the performance via QUALNET simulations, and the results show the improvement of delay time. In the high mobility vehicular systems, it does help to construct an Intelligent Vehicular System.

隨著行動通訊技術日漸進步，隨意網路具備不需要事先建設基礎設施、使用者可以自由移動等特性，未來將很有發展潛力。隨意網路亦具有多跳接的特性，通常都必須由別人幫忙轉送封包到達目的地端。想要使隨意網路能夠普及化，必須提供一個良好的動機，讓隨意網路中的使用者彼此互相合作，願意互相幫忙轉送封包。我們根據參考的論文所提出來的虛擬貨幣交易網路，分析網路資源數量與價錢的關係，提出了一個合理的定價機制。同時也結合隨意網路移動的特性，讓使用者選擇效率較高的路由來傳遞封包。最後我們提出了一個簡單的路由協議，結合了價格機制，而能應用於隨意網路中。實驗結果顯示我們的路由協議能夠提昇整體的網路效能。使用此價格機制結合我們提出的路由協議對使用者而言也是最具經濟效益的。 / In military and rescue applications of mobile ad hoc networks, all the nodes belong to the same authority. Therefore, they are motivated to cooperate in order to support the basic functions of the network. However, the nodes are not willing to forward packets for the benefits of other nodes in civilian applications on mobile ad hoc networks. In view of this, we adopt the “pay for service” model of cooperation, and propose a pricing mechanism combined with routing protocol. The scheme considers users’ benefits and interference effect in wireless networks, and can distribute traffic load more evenly to improve network performance. The simulation results show that our algorithm outperforms other routing protocols. Using our pricing mechanism and routing protocol at the same time can achieve more economical efficiency.

隨著網路訊務流量的快速成長，如何妥善的運用網路資源是一個成功的擁塞控制機制要面對的根本問題。在終端設備上執行的TCP是網路上最廣為使用者使用的傳輸層協定，它有很多不同的版本被設計出來改進使用的效能，例如TCP Reno、TCP Vegas 等。由於TCP所棲身的終端設備並未具有網路內部狀態的資訊，大部份的TCP 擁塞控制機制僅能依賴封包遺失觸發擁塞控制機制，本研究提出TCP Muzha協定，藉由路由器協助，提供網路內部資訊給傳送端，在未發生擁塞前不需依賴封包遺失便可進行適度的傳輸速度控制，以減少因為封包遺失所造成劇烈的傳輸速度下降，並可更快速達到最佳傳輸速度。本研究的設計理念是設法尋找傳送路徑中的瓶頸，進而計算出瓶頸提供的可用頻寬，藉由瓶頸所提供的資訊動態的進行流量控制以充份利用頻寬並避免產生擁塞，增進整體的效能。本研究之重點在於路由器應提供何種資訊及如何運用所獲得的資訊進行動態速率調整。我們提出模糊化的多層級速率調整方法，藉著動態所獲得的細膩資訊做擁塞避免。最後於NS2平台實驗模擬，評估我們所提出的方法，實驗結果中顯示本方法能有效避免擁塞的產生，降低封包遺失，提升整體效能，和TCP Reno共存的環境下不因為Reno侵略性的傳輸方式而降低過多的效能並保有較低的封包遺失率。 / With the tremendous growth of Internet traffic, to utilize network resources efficiently is essential to a successful congestion control protocol. Transmission Control Protocol (TCP) is a widely used end-to-end transport protocol across the Internet. It has several enhencing versions (i.e. TCP Reno, TCP Vegas…) which intend to improve the drawbacks of the initial version of TCP. Most congestion control techniques use trial-and-error-based flow control to handle network congestion. In this paper, we propose a new method (TCP Muzha) that requires routers to feedback their status to the sender. Based on this information, the sender is able to adjust the sending data rate dynamically. Our approach can prevent data rate from decreasing dramatically due to packet loss. It can also help to increase the data rate quickly to where it supposes to be. Our design philosophy is to find out the bottleneck of the path, and its available bandwidth. Our goal is to increase network performance and avoid congestion by using the information obtained from the bottleneck. The design challenges are to determine which information is essential and how to use this information to dynamically adjust the data rate. We also propose the multi-level data rate adjustment method. Congestion can be avoided by dynamically adjusting data rate using this information. Finally, we use NS2 simulator to evaluate the performance of our approaches. From the experiment results, it shows our method can avoid congestion before it actually happen, decrease packet-loss rate and increase the network utilization. In the fairness experiment, our method will only suffer a minor throughputs decreasing when TCP Reno is coexisting.

面對通訊與資訊科技的大幅進步、網際網路的蓬勃發展、以及電信自由化帶來的激烈競爭，通訊網路正在進行一個巨大的變革，企圖將原有Circuit Switching 與 Packet Switching 網路整合成一個單一整合型網路－All-IP網路以支援所有的應用服務。All-IP網路受限於封包交換網路原有的特性，有服務品質問題（QoS）有待克服，因此有必要在All-IP網路上提供服務品質管理機制以實現整合型網路的目標。而要提供適當的QoS 管理，其成功之關鍵主要在於是否能提供一個簡單易行之架構。本論文先提出BBQ(Budget-Based QoS)採用以預算為基礎之服務品質管理，以簡化管理、追求效率，不增加管理複雜度為原則。BBQ提供一個高適用性的管理架構和相關的管理工具，可適用於不同的下層網路架構和不同營運目標的網管政策。 本論文為提出在BBQ管理系統中之端對端服務品質解決方案。透過承載服務的概念，端對端之服務由接取網路和骨幹網路之承載服務提供支援。本論文依據分層負責的精神提出一系列的資源規劃及路徑建構方式，提高網路資源運用效率，並可快速的以即時方式建構具服務品質保證的端對端路徑給使用者。骨幹網路由許多核心網路相連而成，各個核心網路各自獨立規劃內部路徑而端對端的路徑規劃只需選擇所欲通過的核心網路即可，計算量可大幅降低，因此可適用即時的路徑建構。路徑規劃之研究重心為如何挑選最佳核心網路路徑，以規劃具服務品質之端對端路徑並可達到資源之最有效利用。 / The advance in communication and information technology and impact of telecommunication liberalization cause a revolution in telecommunication world. It attempt to merge circuit-switching and packet-switching network into one standalone perform. All-IP is one of those candidates. But All-IP also inherit the characteristics of packet-switching network, the problem of transmission quality. So, we need some management system of quality on All-IP network to achieve the ambition of converged network. In this thesis, we propose BBQ management system. BBQ offers a highly adaptive management architecture and some management tools for operators. Those tools can be used in different underlying network layer and can tune network by different network policy. We propose an End-to-End QoS solution in BBQ management system. By the concept of bearer services, we separate the End-to-End service into Backbone and Stub Network bearer services. According to the hierarchical management, we propose an approach for resource and path planning in order to enhance network efficiency and provide End-to-End path with QoS in real time. Because Backbone Network is connected by Core Networks and each Core Network plans its internal path independently, End-to-End path planning is to choose Core Networks to pass through. This scheme could reduce the enormous computation and fit for real time path setup. The key point of path planning is how to choose the better Core Network path to compose End-to-End path with QoS and reach efficient resource utilization.

耐延遲網路(Delay Tolerant Networks)上的路由協定可以區分為兩大類:flooding-based protocols 跟forwarding-based protocols。網路編碼(Network Coding)是一種編碼技術可以提高訊息傳輸的可靠度；並且運作時不需要知道整體網路的拓樸資訊。 我們提出的演算法結合了flooding-based protocols 跟forwarding-based protocol特性，最主要的概念是讓訊息不是被傳送給每一個節點，而是傳送給朝向目的地或是接近目的地的節點。當節點相遇時，我們的方法會利用節點的路徑、移動方向與速度去預測到達目的地的機率。同時我們利用網路編碼的技巧傳送編碼後的資料來代替訊息的片段，來避免重複傳送多餘的訊息；並讓通訊更加可靠。根據實驗模擬的結果，我們的機制有較好的效能，特別是在頻寬的使用上。 / The routing protocols of delay tolerant networks could be divided in two categories: flooding-based protocols and forwarding-based protocols. Network coding is an encoding technique that could make data transmission more reliable. It operates without the needed of information about the network topology. We proposed a routing protocol integrating the characteristic of flooding-based protocol and forwarding-based protocol. The main idea of our protocol is to let message would not be flooded to every node but to the nodes moving toward or moving closer to destination. When nodes contact with each other, our approach will use the path of node, node’s moving direction and its velocity to estimate the probability to reach the destination of message. At the same time, we exploit network coding to transmit coded block instead of message fragment in order to avoid sending redundant replication, make data transmit more reliable and more robust to packet losses or delays. From the result of simulation, we could see that our protocol have a higher performance especially in the bandwidth consumption compared to other protocols.

隨著網路訊務流量的快速成長和無線網路技術日漸成熟，如何妥善的運用有限的網路資源是一個成功擁塞控制機制要面對的根本問題。TCP為現行網路上最廣為使用的傳輸層協定，並且有許多的不同版本被提出來改進其效能上的問題，例如TCP NewReno，TCP SACK 及TCP Vegas等。然而由於TCP傳送端並未具有網路內部狀態的資訊，如可用頻寬等，大部份的TCP擁塞控制機制僅能依賴封包遺失做為觸發擁塞控制的指標。許多研究指出在無線的環境下TCP無法有效使用有限的資源並且分辨封包遺失的原因，因而造成整體的效能不佳。本篇研究提出一個藉由路由器輔助的TCP擁塞控制協定－TCP Muzha，仰賴路由器提供調速資訊，以幫助傳送端能不依靠封包遺失進行傳輸速度控制，並可更快速的達到最佳的傳輸速度。本研究同時提出模糊化的多層級速率調整方法，藉由動態所獲得的細膩資訊做擁塞避免及因應無線環境下因路由改變或傳輸介質不穩所產生的不必要傳輸速度減低。最後我們在NS2模擬器上對所提出的協定做效能評估，實驗結果顯示本協定除了能有效的避免擁塞外，並能減少不必要的降速及重傳封包的次數。 / Communication networks have evolved tremendously in the past decades. TCP is the most dominant and deployed end-to-end transport protocol across Internet today and will continue to be in the foresee future. It has numerous enhancing versions for wired network such as TCP Reno, TCP NewReno and TCP Vegas to improve the drawbacks of initial version of TCP. As IEEE 802.11 wireless network technology gains popularity, TCP is very likely to be popular for existing applications so far. However due to unawareness of network conditions, regular TCP is not able to fully control the limited resources and distinguish packet loss from congestion loss and random loss. Based on such implicit assumption, many studies have shown this would results in serious performance degradation in wireless environment. In this paper, we proposed a new TCP congestion control mechanism by router-assisted approach which is inspired by the concept of each wireless node playing the roles of terminal and router simultaneously. Based on the information feedback from routers, sender is able to adjust the sending speed dynamically in order to avoid overshooting problem. We also proposed a multilevel date rate adjustment method to control the date rate more precisely. Finally we evaluate the performance of our approach by NS2 simulator. Our proposed protocol has 5~10% higher throughput than TCP NewReno and much less number of retransmission. The fairness requirement is also achieved while our proposed protocol coexists with other major TCP variants.

在DTN(Delay Tolerant Networks)這類的網路架構下，無線節點之 間的通訊連線是採非連續性建立的。DTN 路由協定中, 決定中繼節點 方式大致可以分成兩類:依地理位置考量的路由協定（Geographic Routing Protocal）和依社交模式考量的路由協定（Social-based Routing Portocal）。 由於人與人間的互動是透過社交關係, 但是真實的資訊傳遞又須 仰賴當時的地理位置。因此我們提出的演算法將網路拓墣分成社交層與地理層, 在社交層中利用Social Ally Selection Algorithm 挑選出合適的社交盟友(Social Ally)。在地理層中利用Geographic Messenger Forwarding Algorithm 挑選合適的節點將訊息傳送給朝向目的地或是社交中繼站的節點。根據實驗模擬結果, 我們的路由協定能有較佳的傳遞成功率, 並降低了延遲時間。 / Delay Tolerant networks (DTN) may lack continuous network connectivity. Most of these DTN routing protocol, which attempt to make better routing decision, could be divided in two categories: Geographic routing protocols and Social-based routing protocols. Due to the interaction between people through social behaviors and message transmissions rely on geographic position information, we proposed a routing protocol which network topology is divided into two sub layers: social layer and geographic layer. In social layer, we propose a Social Ally Selection Algorithm to decide social allies that are controlled to improve delivery performance. In geographic layer, we propose a Geographic Messenger Forwarding Algorithm to transmit message to the nodes moving toward to social ally or destination. According to the simulation results, we could show that our routing protocol have higher delivery ratio and lower delay latency compare to other protocols.

在傳統的DTN路由協定中，由於網路拓樸的快速變動，為了能將訊息封包傳送到目的地，通常是透過大量的複製，或是透過資訊的過濾與計算，將封包交由適合的節點來協助傳送。 然而在電池電源有限的條件之下，過於冗餘的封包複製傳遞，或CPU運算的大量使用，將使得節點容易因電量耗盡而失去傳遞的功能，不只是造成整體系統的存活時間(System Lifetime)降低，亦非常不利於維持整體網路的傳遞成功率(Delivery Ratio)。 在旅行的過程中，同行的人們通常具有相同的移動軌跡以及最終目的地，因而形成團體行動的模式；針對這樣的特性，我們採用每個團隊只留下一位領隊來統籌探索鄰居及封包傳遞的概念，透過GPS的資訊輔助來設計出組隊省電機制，延長節點存活時間，進而提升系統存活時間，並在運算複雜度較低且封包冗餘複製亦降低的狀況下，仍保有不錯的傳遞成功率以及較低的效能衰減。 / In traditional routing protocols of DTNs, most of them are using redundancy messages and information computing to make a good relay decision. Due to energy limitation, too many redundant message transmissions or high computing will make nodes die off quickly. It will decrease the system lifetime and diminish the delivery ratio of the whole system. When people go on a tour, friends always form a group due that members have a similar moving path and destination. Based on the features of moving patterns, we design a grouping scheme, namely, Energy-aware Grouping, with the concept that there is only one node awake in a group in charge of contact and message transmissions. With the assistance by GPS, our method has reduced the numbers of redundant message transmissions and information computing. Simulation results show that it can extend the system lifetime with maintaining still good delivery ratio

在耐延遲網路環境下節點的相遇情況不是很頻繁，這可能導致節點間的連線斷斷續續，使得有效地將訊息傳遞成為一件困難的事情。藉由社群感知轉送機制的中間度指標特性，可以來提升傳送成功率。雖然大多數研究幾乎都是將訊息轉送到單一目的地或是多個且已知的目的地。然而，一些應用像是廣告的散佈，要將訊息送給對訊息有興趣的人，但卻不知道是誰。因此，關鍵的問題為如何建立社群網路關係的親密度機制，來選擇作為轉送訊息的節點，並利用群體廣播的方式盡可能有效地傳播至最多可能目標目的地，進而提升效能。 本論文以群播機制和社群感知當作基礎概念，來設計新的轉送訊息的方法和公式化選擇中繼節點的機制。最後，我們使用政治大學實際軌跡來模擬，將模擬結果與其它路由演算法比較，其結果證明我們所提出的方法能提高訊息傳送成功率和正確率，降低傳送延遲時間和傳送訊息的成本。 / In delay tolerant networks (DTNs), nodes infrequently encounter with each others. This results in intermittent connectivity of the nodes, and makes it difficult to deliver the message effectively. A social-aware forwarding scheme can help for successful delivery ratio by utilizing the characteristic of their centrality metric. Most of the previous studies focus on message delivery to single destination or some priori known destinations. However, some applications like advertisement dissemination may not know who will be the interested persons to be delivered. Therefore, the key challenge is how to establish the social relationship strategy to select appropriate nodes as relays, and furthermore to use multicasting to disseminate effectively as many “target” destinations as possible to improve the performance. This thesis developed a new strategy which has a new forwarding message scheme and formulates the selection of the relay nodes based on the concept of the multicasting and the social network. Finally, we used the reality trace data of National Chengchi University to simulate. The simulation results are compared to others DTNs routing protocols as well as other social-aware forwarding schemes. The results showed that our proposed approach can enhance the successful delivery ratio and delivery accuracy, decrease the delivery delay and reduce the delivery overhead.

在耐延遲網路上，離線的使用者，可以透過節點的相遇，以點對點之特定訊息繞送方法，將資訊傳遞至目的地。如此解決了使用者暫時無法上網時欲傳遞資訊之困難。因此，在本研究中，當使用者在某一地區，欲查詢該地區相關之資訊，但又一時無法連上網際網路時，則可透過耐延遲網路之特性，尋求其它同樣使用本服務之使用者幫忙以達到查詢之目的。 本論文提出一適地性服務之資料搜尋方法，以三層式區域概念，及混合式節點型態，並透過資料訊息複製、查詢訊息複製、資料回覆及資料同步等四項策略來達成使用者查詢之目的。特別在訊息傳遞方面，提出一訊息佇列選擇演算法，賦予優先權概念於每一訊息中，使得較為重要之訊息得以優先傳送，藉此提高查詢之成功率及減少查詢之延遲時間。最後，我們將本論文方法與其它查詢方法比較評估效能，其模擬結果顯示我們提出的方法有較優的查詢效率與延遲。 / In Delay Tolerant Networks (DTNs), the offline users can, through the encountering nodes, use the specific peer-to-peer message routing approach to deliver messages to the destination. Thus, it solves the problem that users have the demands to deliver messages while they are temporarily not able to connect to Internet. Therefore, by the characteristics of DTNs, people who are not online can still query some location based information, with the help of users using the same service in the nearby area. In this thesis, we proposed a Location-based content search approach. Based on the concept of three-tier area and hybrid node types, we presented four strategies to solve the query problem. They are Data Replication, Query Replication, Data Reply and Data synchronization strategies. Especially in message transferring, we proposed a Message Queue Selection algorithm. We set the priority concept to every message such that the most important one could be sent first. In this way, it can increase the query success ratio and reduce the query delay time. Finally, we evaluated our approach, and compared with other routing schemes. The simulation results showed that our proposed approach had better query efficiency and shorter delay.