Caching on Named Data Network: a Survey and Future Research

The IP-based system cause inefficient content delivery process. This inefficiency was attempted to be solved with the Content Distribution Network. A replica server is located in a particular location, usually on the edge router that is closest to the user. The user’s request will be served from that replica server. However, caching on Content Distribution Network is inflexible. This system is difficult to support mobility and conditions of dynamic content demand from consumers. We need to shift the paradigm to content-centric. In Named Data Network, data can be placed on the content store on routersthat are closest to the consumer. Caching on Named Data Network must be able to store content dynamically. It should be selectively select content that is eligible to be stored or deleted from the content storage based on certain considerations, e.g. the popularity of content in the local area. This survey paper explains the development of caching techniques on Named Data Network that are classified into main points. The brief explanation of advantages and disadvantages are presented to make it easy to understand. Finally, proposed the open challenge related to the caching mechanism to improve NDN performance

Data Structures and Algorithms for Scalable NDN Forwarding

Named Data Networking (NDN) is a recently proposed general-purpose network architecture that aims to address the limitations of the Internet Protocol (IP), while maintaining its strengths. NDN takes an information-centric approach, focusing on named data rather than computer addresses. In NDN, the content is identified by its name, and each NDN packet has a name that specifies the content it is fetching or delivering. Since there are no source and destination addresses in an NDN packet, it is forwarded based on a lookup of its name in the forwarding plane, which consists of the Forwarding Information Base (FIB), Pending Interest Table (PIT), and Content Store (CS). In addition, as an in-network caching element, a scalable Repository (Repo) design is needed to provide large-scale long-term content storage in NDN networks. Scalable NDN forwarding is a challenge. Compared to the well-understood approaches to IP forwarding, NDN forwarding performs lookups on packet names, which have variable and unbounded lengths, increasing the lookup complexity. The lookup tables are larger than in IP, requiring more memory space. Moreover, NDN forwarding has a read-write data plane, requiring per-packet updates at line rates. Designing and evaluating a scalable NDN forwarding node architecture is a major effort within the overall NDN research agenda. The goal of this dissertation is to demonstrate that scalable NDN forwarding is feasible with the proposed data structures and algorithms. First, we propose a FIB lookup design based on the binary search of hash tables that provides a reliable longest name prefix lookup performance baseline for future NDN research. We have demonstrated 10 Gbps forwarding throughput with 256-byte packets and one billion synthetic forwarding rules, each containing up to seven name components. Second, we explore data structures and algorithms to optimize the FIB design based on the specific characteristics of real-world forwarding datasets. Third, we propose a fingerprint-only PIT design that reduces the memory requirements in the core routers. Lastly, we discuss the Content Store design issues and demonstrate that the NDN Repo implementation can leverage many of the existing databases and storage systems to improve performance

Recent advances in connected vehicles via information-centric networking

V2X communication technology allows vehicles to communicate with each other, infrastructures as well as other parties. It is considered as a vital role in realizing future Intelligent Transport System (ITS). On one hand V2X is facing various expectations that requested by different features of applications, On the other hand, V2X has to overcome problems caused by the natures of high mobile vehicle environment. ICN proposed as the a substitution for future Internet rely on its naming design is likely to associate with V2X well in contrast to convention TCP/IP solution. This paper viewed recent relevant literatures from which unaddressed problems are identified with discussion of possible solutions. From this work, we are positioning our future efforts to fulfil such gaps

정보 중심 네트워킹에서의 콘텐트 탐색 및 데이터 오프로딩

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2015. 8. 권태경.현재의 인터넷은 자원 공유를 목적으로 호스트간 통신 패러다임에 기반하여 설계되었지만, 오늘날 인터넷 사용 패턴은 콘텐트 획득에 집중되어있다. 이러한 이유로, 대부분의 인터넷 트래픽은 비디오 서비스나 P2P 파일 공유와 같은 콘텐트 획득에 의해 발생하고 있는 상황이다. 하지만, 현재 인터넷의 구조와 실제 사용 패턴의 괴리는 비효율적인 콘텐트 전달 (예, 동일한 인기있는 콘텐트에 대한 중복된 콘텐트 전송)을 야기하고 있고, 이는 트래픽 폭발 문제로 이어지고 있다. 이러한 이슈를 다루기 위해 (i) 인터넷 구조를 새롭게 설계하거나 (ii) 데이터 오프로딩 기법을 통해 네트워크 트래픽을 줄이려는 시도들이 있다. 본 학위 논문에서는 정보 중심 네트워킹과 정보 중심의 차량 네트워크라는 두가지 영역에서의 트래픽 감소 기법에 대해 탐구한다. 첫 번째로, 정보 중심 네트워킹을 위한 트래픽 감소 콘텐트 탐색 기법을 제안한다. 정보 중심 네트워킹은 트래픽 폭발과 같은 현재 인터넷의 문제점을 해결하기 위해, 초기 단계부터 인터넷 구조를 새롭게 설계하자는 방향으로 제안되었다. 정보 중심 네트워킹은 가까이에 존재하는 캐시된 콘텐트를 이용하거나 동일한 콘텐트 전송에 대한 중복된 전송을 줄이는 것을 통해 네트워크 트래픽 감소와 같은 이득을 제공할 수 있다. 하지만, 이전의 연구들은 이러한 캐시된 콘텐트를 이용하기 위해 기회주의적 캐시 일치 방식에 의존을 하고 있다. 이러한 방식은 콘텐트 소스로 가는 경로에 존재하는 캐시된 콘텐트만 이용할 수 있기 때문에 네트워크 곳곳에 있는 네트워크 내재 저장 공간을 충분히 이용하지 못하는 한계가 있다. 제안하는 기법인 SCAN은 네트워크에 산재된 캐시된 콘텐트를 더 잘 이용하기 위해서 가까이에 존재하는 캐시된 콘텐트를 탐색한다. 이를 위해 SCAN은 블룸 필터를 사용하여 주변 라우터들 사이에서 캐시된 콘텐트에 대한 정보를 교환한다. 시뮬레이션을 통해 SCAN은 기회주의적 캐시 일치 방식의 기법에 비해 평균 홉 거리, 트래픽 양, 링크간 로드 분배에서 더 나은 성능을 보임을 알 수 있다. 다음으로, 정보 중심의 차량 네트워크를 위한 트래픽 오프로딩 기법을 제안한다. 무선 환경에서 급증하고 있는 모바일 트래픽은 모바일 네트워크 제공자에게 심각한 우려가 되고 있다. 이러한 트래픽 폭발 문제를 다루기 위해, 트래픽을 셀룰러 네트워크에서 WiFi 핫스팟이나 펨토셀과 같은 다른 네트워크로 오프로딩하려는 연구들이 있었다. 본 연구에서는 기존의 시도에서 더 나아가서 데이터 오프로딩을 위한 차량 네트워크의 잠재적 장점에 집중하여 차량 네트워크를 이용한 데이터 오프로딩 프레임워크인 DOVE를 제안한다. 제안하는 데이터 오프로딩 프레임워크는 차량 내 데이터 서비스를 위해 필요한 셀룰러 트래픽을 비용 효과가 높은 방식으로 감소시킬 수 있다. DOVE에서는 오프로딩을 목적으로 차량 이동 경로를 이용하고, 경제적인 비용 절감을 목적으로 차량에서 요청되는 콘텐트 파일들은 셀룰러 네트워크 대신 차량 네트워크를 통해 전달된다. 이를 위해 오프로딩 위치를 선택하는 문제를 시공간적 집합 덮개 문제로 만들고, 차량 이동 경로를 이용한 시간 예측 기반의 집합 덮개 알고리즘을 제안한다. 시뮬레이션 결과에 따르면, DOVE 프레임워크는 차량 네트워크를 통한 오프로딩을 수행하여 57%의 셀룰러 링크 사용량을 크게 감소시킬 수 있다.While the architecture of current Internet was designed based on the host-to-host communication paradigm for resource sharing, today's Internet usage has been concentrated on content retrievals. As a result, most of Internet traffic is generated by the content retrievals, such as video service and P2P file sharing. However, the discrepancy between the current Internet architecture and the real usage pattern causes inefficient content deliveries (e.g., duplicated content transmission for the same popular content), which leads to traffic explosion problem. To address such issues, there have been a lot of efforts to reduce the network traffic by (i) redesigning the Internet architecture and (ii) proposing data offloading schemes. In this dissertation, we investigate traffic reduction schemes in two different domains, information-centric networking and information-centric vehicular networks. First, we propose a traffic-reduction content-discovery scheme for information-centric networking (ICN). ICN has been proposed to resolve the problem of current Internet such as traffic explosion by redesigning the Internet architecture in a clean-slate manner. ICN can provide substantial benefits such as network traffic reduction by exploiting a nearby (cached) copy of content and reducing duplicated transmissions for the same content request. However, prior studies usually rely on an opportunistic cache-hit (happen-to-meet) to utilize the cached contents. In the happen-to-meet fashion, only the content cached on the path towards the content source can be utilized, which limits the network-wide usage of the in-network storages. To exploit cached contents better, our proposed scheme SCAN discovers nearby content copies. SCAN exchanges the cached content information among the neighbor routers using Bloom filters for the content discovery. With extensive simulations, SCAN shows better performance than a happen-to-meet cache-hit scheme in terms of average hop counts, traffic volume, and load balancing among links. Next, we propose a traffic offloading scheme for information-centric vehicular network. In wireless environments, the increasing mobile traffic is becoming a serious concern for mobile network providers. To address the traffic explosion problem, there have been a lot of efforts to offload the traffic from cellular networks to other networks, such as WiFi hotspots and femtocells. Our work moves forward from prior studies by focusing on the potential benefits of vehicular networks for data offloading. In particular, we propose a Data Offloading framework using Vehicular nEtworks (DOVE), which reduces the cellular traffic for in-vehicle data services in a cost effective way. DOVE exploits vehicle trajectories for offloading purposes so that content files requested by vehicles can be delivered via vehicular networks rather than cellular networks for economical purposes. We formulate the problem of selecting offloading positions as a spatio-temporal set-covering problem, and propose a time-prediction based set-covering algorithm using vehicle trajectories. Simulation results show that our DOVE framework can significantly reduce 57% of cellular link usage by performing data offloading through vehicular networks.I. Introduction 1 II. Content Discovery for Information-Centric Networking 4 2.1 Introduction 4 2.2 Related Work 7 2.2.1 Named Data Networking (NDN) 7 2.2.2 ICN-based Schemes 8 2.2.3 Approaches using BFs 10 2.3 SCAN Architecture 11 2.3.1 SCAN Description 11 2.3.2 SCAN Operation 16 2.3.3 Discussion 19 2.4 CIB Maintenance in SCAN 21 2.4.1 Information Unit 21 2.4.2 Information Exchange 22 2.4.3 Information Decay 23 2.5 Performance Evaluation 25 2.5.1 Content Discovery Performance 27 2.5.2 Network-wide Performance 28 2.5.3 Effect of Cache Size 30 2.5.4 Effect of Scanning Depth 32 2.5.5 Effect of Information Decay Probability 34 2.5.6 Effect of BF Size 36 2.5.7 Effect of BF Exchange Interval 39 2.5.8 Comparison with ICN-enhancements 39 III. Data Offloading for Information-Centric Vehicular Networks 42 3.1 Introduction 42 3.2 Related Work 44 3.3 Problem Formulation 46 3.3.1 Target Scenario and Goal 46 3.3.2 DOVE Components and Assumptions 46 3.3.3 Design Principles using RNs 49 3.3.4 The Concept of Offloading in DOVE 50 3.4 Design and Operations of DOVE 51 3.4.1 Travel Time Prediction 51 3.4.2 The Operation of TCC 53 3.4.3 The Selection Algorithm for Offloading Positions 54 3.4.4 The Selection of Providers 59 3.4.5 The Operation of Vehicles using Offloading Positions 59 3.5 Performance Evaluation 60 3.5.1 Overall Performance of Data Offloading 61 3.5.2 The Impact of Vehicle Number 67 3.5.3 The Impact of Vehicle Speed 68 3.5.4 The Impact of Waiting Time 70 3.5.5 The Impact of Deployment Ratio and Tolerance Time 71 IV. Conclusion 74 Bibliography 76 Korean Abstract 82Docto

A Comparative Analysis of Bloom Filter-based Routing Protocols for Information-Centric Networks

Bloom filter-based routing protocols for Named Data Networking (NDN) aim at facilitating content discovery in NDN. In this paper, we compare the performance of two Bloom filter-based routing protocols, namely BFR and COBRA. BFR is a push-based routing protocol that works based on Bloom filter-based content advertisements, while COBRA is a pull-based routing protocol that operates based on route traces left from previously retrieved content objects, which are stored in Stable Bloom Filters. In this paper, we show that BFR outperforms COBRA in terms of average memory needed for storing routing updates, average round-trip delay, normalized communication overhead, total Interest communication overhead, and mean hit distance

Implementation of Cache Attack on Real Information Centric Networking System

Network security is an ongoing major problem in today’s Internet world. Even though there have been simulation studies related to denial of service and cache attacks, studies of attacks on real networks are still lacking in the research. In this thesis, the effects of cache attacks in real information-centric networking systems were investigated. Cache attacks were implemented in real networks with different cache sizes and with Least Recently Used, Random and First In First Out algorithms to fill the caches in each node. The attacker hits the cache with unpopular content, making the user request that the results be fetched from web servers. The cache hit, time taken to get the result, and number of hops to serve the request were calculated with real network traffic. The results of the implementation are provided for different topologies and are compared with the simulation results

Named Data Networking in Vehicular Ad hoc Networks: State-of-the-Art and Challenges

International audienceInformation-Centric Networking (ICN) has been proposed as one of the future Internet architectures. It is poised to address the challenges faced by today's Internet that include, but not limited to, scalability, addressing, security, and privacy. Furthermore, it also aims at meeting the requirements for new emerging Internet applications. To realize ICN, Named Data Networking (NDN) is one of the recent implementations of ICN that provides a suitable communication approach due to its clean slate design and simple communication model. There are a plethora of applications realized through ICN in different domains where data is the focal point of communication. One such domain is Intelligent Transportation System (ITS) realized through Vehicular Ad hoc NETwork (VANET) where vehicles exchange information and content with each other and with the infrastructure. To date, excellent research results have been yielded in the VANET domain aiming at safe, reliable, and infotainment-rich driving experience. However, due to the dynamic topologies, host-centric model, and ephemeral nature of vehicular communication, various challenges are faced by VANET that hinder the realization of successful vehicular networks and adversely affect the data dissemination, content delivery, and user experiences. To fill these gaps, NDN has been extensively used as underlying communication paradigm for VANET. Inspired by the extensive research results in NDN-based VANET, in this paper, we provide a detailed and systematic review of NDN-driven VANET. More precisely, we investigate the role of NDN in VANET and discuss the feasibility of NDN architecture in VANET environment. Subsequently, we cover in detail, NDN-based naming, routing and forwarding, caching, mobility, and security mechanism for VANET. Furthermore, we discuss the existing standards, solutions, and simulation tools used in NDN-based VANET. Finally, we also identify open challenges and issues faced by NDN-driven VANET and highlight future research directions that should be addressed by the research community

Service Provisioning in Edge-Cloud Continuum Emerging Applications for Mobile Devices

Disruptive applications for mobile devices can be enhanced by Edge computing facilities. In this context, Edge Computing (EC) is a proposed architecture to meet the mobility requirements imposed by these applications in a wide range of domains, such as the Internet of Things, Immersive Media, and Connected and Autonomous Vehicles. EC architecture aims to introduce computing capabilities in the path between the user and the Cloud to execute tasks closer to where they are consumed, thus mitigating issues related to latency, context awareness, and mobility support. In this survey, we describe which are the leading technologies to support the deployment of EC infrastructure. Thereafter, we discuss the applications that can take advantage of EC and how they were proposed in the literature. Finally, after examining enabling technologies and related applications, we identify some open challenges to fully achieve the potential of EC, and also research opportunities on upcoming paradigms for service provisioning. This survey is a guide to comprehend the recent advances on the provisioning of mobile applications, as well as foresee the expected next stages of evolution for these applications

On social and technical aspects of managing mobile Ad-hoc communities

Soziale Software beschreibt eine Klasse von Anwendungen, die es Benutzern erlaubt ueber das Internet mit Freunden zu kommunizieren und Informationen auszutauschen. Mit zunehmender Leistungsfaehigkeit mobiler Prozessoren verwandeln sich Mobiltelefone in vollwertige Computer und eroeffnen neue Moeglichkeiten fuer die mobile Nutzung sozialer Software. Da Menschen Mobiltelefone haeufig bei sich fuehren, koennen vergleichbare mobile Anwendungen staerker auf ihre unmittelbare Umgebungssituation zugeschnitten werden. Moegliche Szenarien sind die Unterstuetzung realer Treffen und damit verbundenen Mitgliederinteraktionen. Client-Server-Plattformen, die dabei haeufig zum Einsatz kommen wurden allerdings nie fuer solche hochflexiblen Gruppensituationen konstruiert. Mobile Encounter Netzwerke (MENe) verprechen hier mehr Flexibilitaet. Ein MEN stellt eine mobiler Peer-to-Peer-Plattformen dar, das ueber ein kurzreichweitiges Funknetz betrieben wird. Mit diesem Netzwerk werden Beitraege ueber einen raeumlichen Diffusionsprozess von einem mobilen Endgeraet zum naechsten verbreitet. Das hat zwei entscheidende Vorteile: Zunaechst ist der direkte Nachrichtenaustausch besser geeignet zur Verbreitung von situationsspezifischer Information, da die Informationsrelevanz mit ihrer Entfehrnung abnimmt. Gleichzeitig koennen aber auch Inhalte, die fuer einen breiten Interessenkreis bestimmt sind ueber Mitglieder mit herausragenden Mobilitaetscharakteristik in weit entfernte Gebiete transportiert werden. Ein Nachteil ist jedoch der hohe Ressourcenverbrauch. Zur Loesung dieses Problems entwickeln wir ein Rahmenwerk zur Unterstuetzung mobiler ad-hoc Gruppen, das es uns erlaubt, Gruppensynergien gezielt auszunutzen. Dieses Rahmenwerk bietet Dienstleistungen zur Verwaltung der Gruppendynamik und zur Verbreitung von Inhalten an. Mittels soziale Netzwerkanalyse wird die technische Infrastruktur ohne notwendige Benutzereingriffe kontinuierlich an die reale Umgebungssituation angepasst. Dabei werden moegliche Beziehungen zwischen benachbarten Personen anhand frueher Begegnungen analysiert, spontane Gruppenbildungen mit Clusterverfahren identifiziert und jedem Gruppenmitglied eine geeignete Rolle durch eine Positionsanalyse zugewiesen. Eine Grundvorraussetzung fuer eine erfolgreiche Kooperation ist ein effizienter Wissensaustausch innerhalb einer Gemeinschaft. Wie die Small World-Theorie zeigt, koennen Menschen Wissen auch dann effizient verbreiten, wenn ihre Entscheidung nur auf lokaler Umgebungsinformation basiert. Verschiedene Forscher machten sich das zu nutze, indem sie kurze Verbreitungspfade durch eine Verkettung hochvernetzter Mitglieder innerhalb einer Gemeinschaft konstruierten. Allerdings laesst sich dieses Verfahren nicht einfach auf MENe uebertragen, da die Transferzeit im Gegensatz zu dem drahtgebundenen Internet beschraenkt ist. Unser Ansatz beruht daher, auf der von Reagan et al. vorgestellten Least Effort Transfer-Hypothese. Diese Hypothese besagt, dass Menschen Wissen nur dann weitergeben, wenn sich der Aufwand zur Informationsuebertragung innerhalb bestimmter Grenzen bewegt. Eine erfolgreiche Wissensuebertragung haengt in diesem Fall vom Hintergrundwissen aller Beteiligter ab, was wiederum von unterschiedlichen kognitiven und sozialen Faktoren abhaengt. Entsprechend leiten wir ein Diffusionsverfahren ab, dass in der Lage ist, Inhalte in verschiedene Kompexitaetstufen einzuteilen und Datenuebertragungen an die vorgefundene soziale Situation anzupassen. Mit einem Prototyp evaluieren wir die Machbarkeit der Gruppen- und Informationsmanagementkomponente unseres Rahmenwerkes. Da Laborexperimente keinen ausreichenden Aufschluss ueber Diffusionseigenschaften im groesseren Massstab geben koennen, simulieren wir die Beitragsdiffusion. Dazu dient uns eine Verkehrsimulation, bei der Agenten zusaetzlich mit aktivitaetsbezogenen, sozialen und territorialen Modellen erweitern werden. Um eine realitaetsnahe Simulation zu gewaehrleisten, werden diese Modelle in Uebereinstimmung mit verschiedenen Studien zum Stadtleben generiert. Der technische Uebertragungsprozess wird anhand der Ergebnisse einer vorangegangenen Prototypuntersuchung parametrisiert. Waehrend eines Simulationslaufes bewegen sich Agenten auf einem Stadtplan und sammeln Kontakt- und Beitragsdaten. Analysiert man anschliessend die Netzwerktopologie auf Small World-Eigenschaften, so findet man eine Netzstruktur mit einer ausgepraegten Neigung zum Clustering (Freundschaftsnetzwerke) und einer ueberdurschnittlichen kurzen Weglaenge. Offensichtlich reicht die Alltagsmobilitaet aus, um ausreichend viele Verknuepfungen zwischen Gemeinschaftmitgliedern zu bilden. Die nachfolgende Diffusionsanalyse zeigt, dass vergleichbare Reichweiten wie bei einem flutungsbasierten Ansatz erzielt werden, allerdings mit anfaenglichen Verzoegerungen. Da unser Verfahren bei einem Ortswechsel die Anzahl der Informationsuebermittler auf zentrale Gruppenmitglieder begrenzt, steht mehr Bandbreite fuer den Datenaustausch zur Verfuegung. Herkoemliche Mitglieder (ohne Leitungsaufgaben) tauschen Inhalte vornehmlich in zeitunkritschen Situationen aus. Das hat den positiven Nebeneffekt, dass im Cache erheblich weniger Kopien aussortiert werden muessen. Wechselt man waehrend der Simulation die Beitragskategorie so erkennt man, dass zeitabhaengige Inhalte besser ueber regelmaessige Kontakte und zeitunabhaengig Inhalte durch zufaellige Kontakte verbreitet werden. Eine abschliessende Precision-Recall Analyse zeigt, dass herkoemmliche Gruppenmitglieder eine bessere Genauigkeit (Precision), und zentrale Mitglieder eine bessere Trefferquote (Recall) im Vergleich zu traditionellen Ansaetzen besitzen. Eine Erklaerung dafuer ist, dass der von uns gewaehlte gruppenbasierte Cacheansatz zu weniger Saeuberungszyklen aller Gruppenmitglieder fuehrt und somit nachhaltiger ausgerichtet ist.Social software encompasses a range of software systems that allow users to interact and share data. This computer-mediated communication has become very popular with social networking sites like Facebook and Twitter. The evolvement of smart phones toward mobile computers opens new possibilities to use social software also in mobile usage scenarios. Since mobile phones are permanently carried by their owners, the support focus is, however, much stronger set on promoting and augmenting real group gatherings. Traditional client-server platforms are not flexible enough to support complex and dynamic human encounter behavior. Mobile encounter networks (MENs) which represent a mobile peer-to-peer platform on top of a short range wireless network promise better flexibility. MENs diffuse content from neighbor-to-neighbor in a spatial diffusion process. For physical group gatherings this is advantageous for two reasons. Direct device-to-device interactions encourage sharing of situation-dependent content. Moreover, content is not necessarily locked within friend groups and may trigger networking effects by reaching larger audiences through user mobility. One disadvantage is, however, the high resource usage. We develop a social software framework for mobile ad-hoc groups, which partly solves this problem. This framework supports services for the management of group dynamics and content diffusion within and between groups. Social network analysis as an inherent part of the framework is used to adapt internal community states continuously with real world encounter situations. We hereby qualify interpersonal relationships based on encounter and communication statistics, identify social groups through incremental clustering and assign diffusion roles through position analysis. To achieve efficient content dissemination we make use of social diffusion phenomena. Other researchers have experimented extensively with the small world model as it proofs that people transfer knowledge based on local knowledge but are still capable of diffusing it efficiently on a global scale. Their approach is often based on identifying short paths through member connectivity. However, this scenario is not applicable in MENs as transfer time is limited in contrast to the wired Internet. Our approach is therefore based on the least effort transfer theory. Following Reagan et al., who first postulated this hypothesis, people transfer knowledge only if the transfer effort is within specific limits, which depends on different social and cognitive factors. We derive routing mechanisms, which are capable of distinguishing between different content complexities and apply information about peer's expertise and social network to identify advantageous paths and content transfers options. We evaluate the feasibility of the group management and content transfer component with prototypes. Since labor settings do not allow to obtain information about large scale diffusion experiences, we also conduct a multi-agent simulation to evaluate the diffusion capabilities of the system. Experiences from an earlier prototype implementation have been used to quantify the technical routing process. To emulate realistic community life, we assigned to each agent an individual daily agenda, social contacts and territory preferences specified according to outcomes from different urban city life surveys. During the simulation agents move on a city map according to these models and collect contact and content specific data. Analyzing the network topology according to small world characteristics shows a structure with a high tendency for clustering (friend networks) and a short average path length. Daily urban mobility creates enough opportunities to form shortcuts through the community. Content diffusion analysis shows that our approach reaches a similar amount of peers as network flooding but with delays in the beginning. Since our approach artificially limits the number of intermediates to central community peers more bandwidth is available during traveling and more content can be transferred as in the case of the flooding approach. Ordinary peers seem to have significantly fewer content replications if an unlimited cache is assumed proofing that our mechanism is more efficient. By varying the content type used during the simulation we recognize that time dependent content is better disseminated through frequent contacts and time independent content through random contacts. Performing a precision-recall analysis on peers caches shows that ordinary peers gain an overall better context precision, and central peers a better community recall. One explanation is that the shared cache approach leads to fewer content replacements in the cache as for instance the least recently used cache strategy