A density-aware probabilistic interest forwarding method for content-centric vehicular networks

<p class="JESTECAbstract">Content Centric Networking (CCN) is a modern architecture that got wide attention in the current researches as a substitutional for the current IP-based architecture. Many studies have been investigated on this novel architecture but only little of them focused on Pending Interest Table (PIT) which is very important component in every CCN router. PIT has fundamental role in packet processing in both upstream process (Interest packets) and downstream process (Data packets). PIT must be fast enough in order to not become an obstruction in the packet processing and also it must be big enough to save a lot of incoming information. In this paper, we suggest a new PIT design and implementation named CF-PIT for CCN router. Our PIT design depends on modifying and utilizing an approximate data structure called Cuckoo filter (CF). Cuckoo filter has ideal characteristics like: high insertion/query/deletion performance, acceptable storage demands and false positive probability which make it with our modification convenient for PIT implementation. The experimental results showed that our CF-PIT design has high performance in different side of views which make it very suitable to be implemented on CCN routers.</p>

Today’s Internet is no longer fit for the user traffic patterns that it is serving. To remedy this cognitive mismatch between the service platform and the traffic it serves, several future Internet architectures such as Content-Centric Networking (CCN) have been proposed recently with the aim of re-engineering the Internet towards supporting content-oriented communication. With the mechanisms to transform the Internet from being host-centric to becoming content-centric well spelt-out in the CCN standard, the problem of how to manage congestion and control traffic flows in CCN is still left open. Existing congestion control mechanisms for the current Internet have been shown to be ill-suited for CCN making the case for a clean-slate design of congestion control and traffic management mechanisms for CCN. In this thesis, we identify the fact that congestion in CCN can take place not only in the transmission buffer but also in the pending interest table (PIT), a data structure that keeps track of all requests received from downstream nodes and forwarded to upstream nodes. Keeping this in mind, we make three contributions in this thesis: First, we characterize the PIT occupancy distribution using a 2-dimensional continuous-time Markov chain model to study the impact of PIT entry timeout and interest retransmission on the interest blocking probability. Second, given the dependence of the PIT occupancy on the PIT entry timeout and interest retransmission, we investigate the performance of two types of routers in lossy networks: no-rtx routers that do not retransmit pending interests upon timeout, and rtx routers that do retransmit pending interests periodically. Based on this, we further introduce a novel adaptive method to estimate the PIT entry timer that relies on the data chunk response delays to replace the currently used fixed-value method introduced in CCN. Finally, identifying that content requesters should be responsible for retransmitting timeout requests and that estimates of the retransmission timeout should reflect the network load conditions, we propose a novel congestion control mechanism for CCN that takes into account both the PIT and the transmit buffer. Using the PIT occupancy as a good estimator for the data flight size to arrive to the node in the near future, we design a congestion avoidance mechanism that adjusts the request rate based on anticipated congestion.

최근에 기존 IP기반과는 다른, 정보 중심 네트워킹이 부각되고 있으며 그 중의 하나인 Content-Centric Networking(CCN)은 Van Jacobson에 의해 처음 제안되어 대표적인 정보 중심 네트워킹 패러다임으로 활발히 연구되고 있다. CCN은 콘텐츠 자체에 대한 접근과 전달에 목표를 두고 라우터에서 콘텐츠의 배분이 가능토록 하여 IP 방식보다 좀 더 빠르게 콘텐츠가 전달되도록 하는 장점을 가지고 있다. 하지만, CCN은 정보요청자 기준의 통신(pull-based)으로 사전 요청패킷의 전송없이 정보를 분배하는 것이 제한된다. 또한, PIT(Pending Interest Table)의 사용으로 DDoS 공격 등을 받을 시 PIT 메모리 오버로드의 문제점이 있다. 이에 본 논문은 CCN에서 요청패킷 없이 정보를 전달하는 push-based 기법과 PIT 오버로드 상황에서 데이터 전달이 가능하도록 Interest Group Pushing Table(IGPT)을 활용한 정보전송 방법을 제안한다. 제안하는 기법은 데이터 전송의 신속성 및 보안성 향상 측면에서 기존의 기법보다 동일 시간동안 많은 양의 콘텐츠 전송이 가능하다. Recently, Information-Centric Networking(ICN), different from traditional IP-based networking, has been highlighted. Content-Centric Networking(CCN), proposed by Van Jacobson, is a representative scheme of the ICN architectures. It can deliver messages slightly faster than the IP-based networking by focusing on the access and delivery to the content itself. However, CCN is restricted to distribute the information without transmitting the request packet in advance because it is pull-based architecture by content requester. In addition, it has a problem that the Pending Interest Table(PIT) could be overloaded easily when DDoS attack happens. In this paper, we suggest an algorithm using a push-based scheme without request packets and overcoming PIT overload situation by Interest Group Push Table(IGPT). The proposed scheme enables to transmit a large amount of content than an existing scheme during the same amount of time in terms of timely-delivery and security.

Ahstract-Content-Centric Networking (CCN) is an emerging Internet paradigm where the content is treated as the first-class citizen and content names are used for network layer communication instead of IP addresses. Use of CCN in wireless environment can cause various issues such as re-transmissions, collisions, delay and link failure. One of the key issues that affects the performance of CCN is the management of Pending Interest Table (PIT). PIT stores each broadcasted Interest packet forwarded upstream towards the content provider and is purged either when the requested content is returned or the PIT Entry Lifetime (PEL) expires. The conventional method in CCN for PEL does not considering the network impairments such as channel error, and congestion. As a result, timeout occurs, and Interest packets are re-transmitted for the chunks that have been dropped or delayed. Due to limited size of storage in wireless CCN, all new incoming Interest packets (including retransmissions) affect the performance of network by bloating PIT. In this paper, therefore, we propose a scheme that purges the PIT entries quickly by prefetching the un-obtained content in advance. Simulation results show that proposed protocol performs better as comparing with the conventional CCN and another recent proposed protocol.

Vehicular Ad hoc Network (VANET) has become a very interesting technology for future generation vehicles. This is mainly due to its embedded and promising advantages which primarily include improvement of safety conditions on public road through exchange of critical safety messages amongst involved nodes. The success of VANET heavily relies on successful messages dissemination amongst involved vehicles. However, a successful message exchange can only be possible if the transmission medium is collision free. Under the Intelligent Transportation System (ITS), the cooperative Awareness messages (CAM) have to be transmitted at the rate of 10 Hz as per standard. To account for congestion management, the Distributed Congestion Control (DCC) mechanism was proposed. However, under higher node density, the DDC becomes inefficient and dramatically contribute to the deterioration of the VANET environment. The present work proposes a Dynamic Broadcast Storm Mitigation Algorithm (DBSMA) which can be used to combat the broadcast storm problem in a Vehicular Network (VN). Results from several simulations confirmed that the DBSMA has a potentiality to conquer the effect of broadcast storm by offering more than 150% improved efficiency against the DCC approach. Another advantage of the DBSMA is that it is simple to compute and easy to implement.

Using Interests (requests that elicit content) and maintaining per-Interest forwarding state in Pending Interest Tables (PIT) are integral to the design of the Named Data Networking (NDN) and Content-Centric Networking (CCNx) architectures. However, using PITs makes the network vulnerable to Interest-flooding attacks, and PITs can become very large. It is shown that in-network caching eliminates the need for Interest aggregation and obviates the use of PITs. A new approach to content-centric networking (CCN-GRAM) is introduced that provides all the benefits of NDN and CCNx, eliminates the use of PITs by means of anonymous datagrams, and is immune to Interest-flooding attacks. Routers maintain routes to the anonymous origins of Interests using an on-demand routing approach in the data plane that can also be used to provide native support for multicasting in the dat a plane. Simulation experiments show that the number of forwarding entries required in CCN-GRAM is orders of magnitude smaller than the number of PIT entries.

Radient: Scalable, memory efficient name lookup algorithm for named data networking

Vehicular Content-Centric Networks (VCCN) has been proposed and emerged as an upcoming Internet technology for the Vehicular Ad-hoc Networks (VANETs). However, VCCN architecture faces many challenges including Consumer/Provider mobility, Flooding, Interest/Data packet forwarding, Forwarding selection and Congestion control. Consumer vehicle broadcasts (i.e., requests) the interest packet. Relay nodes vehicles receiving this interest packet and performs search (Content Storage, Pending Interest Table and Forward Interest Base) operations on it and then rebroadcasts the interest message in case of no content match. These search (Content Storage, Pending Interest Table, and Forward Interest Base) operations cause delay and duplication's of interest packets. In our paper, we propose a routing protocol scheme named Intersection Based Forwarder Selection (IBFS) to mitigate the interest broadcast storm and disconnected link within the network. In IBFS, each vehicle shares its trajectory information with its neighboring vehicles. All vehicles store/save trajectory information in its Neighbor Table (NT), which helps to select the best interest relay/forwarder vehicle on the basis of matching trajectory information with the consumer vehicle. We have also considered the other metrics i.e. velocity and hop count. IBFS protocol overcomes the end-to-end delay (low latency), ISD (Interest Satisfaction Delay), communication overheads and minimum number of interest forwarded with the reliable interest and data packet transmission.

Content-centric networking (CCN) is an innovative network architecture that is being considered as a successor to the Internet. In recent years, CCN has received increasing attention from all over the world because its novel technologies (e.g., caching, multicast, aggregating requests) and communication based on names that act as addresses for content have the potential to resolve various problems facing the Internet. To implement these technologies, however, requires routers with performance far superior to that offered by today's Internet routers. Although many researchers have proposed various router components, such as caching and name lookup mechanisms, there are few router-level designs incorporating all the necessary components. The design and evaluation of a complete router is the primary contribution of this paper. We provide a concrete hardware design for a router model that uses three basic tables — forwarding information base (FIB), pending interest table (PIT), and content store (CS) — and incorporates two entities that we propose. One of these entities is the name lookup entity, which looks up a name address within a few cycles from content-addressable memory by use of a Bloom filter; the other is the interest count entity, which counts interest packets that require certain content and selects content worth caching. Our contributions are (1) presenting a proper algorithm for looking up and matching name addresses in CCN communication, (2) proposing a method to process CCN packets in a way that achieves high throughput and very low latency, and (3) demonstrating feasible performance and cost on the basis of a concrete hardware design using distributed content-addressable memory.

Efficient content distribution is a critical challenge in vehicular networks (VANETs). This is due to the characteristics of vehicular networks, such as high mobility, dynamic topologies, short-lived links and intermittent connectivity between vehicles. Recently, information-centric networking (ICN) has been proposed to VANET scenarios for improving content delivery of infotainmentapplications. However, ICN in VANETs suffers from the Interest transmission broadcast problem, which results in a waste of resources and diminishes the performance of VANETs' applications. In this paper, we propose the link stability-based Interest forwarding for content request (LISIC) protocol, in order to tackle the Interest broadcast storm problem during a content search in information-centric VANETs. The proposed protocol controls Interesttransmission by prioritizing neighboring vehicles with more stable links with the current sender. Simulation results show that the proposed protocol improves the content delivery rate by 40% while decreases the Interest packet transmissions by 26%, in scenario of a low number of content producers in the network.

In VANETs, there are many applications that use broadcast communication as a fundamental operational tool, in disseminating information of interest to other road users under the umbrella of both safety and entertainment applications. Recently, the probabilistic broadcasting scheme is suggested as an efficient broadcast approach. Although a number of probabilistic schemes found in the literature, they still suffer from a high level of rebroadcast redundancy, which often leads to the Broadcast Storm Problem (BSP). Thus, in this paper a new efficient probabilistic broadcast scheme is developed, to target both achieving a high delivery ratio and reducing broadcast redundancy. Using simulation experiment, we compared the performance of the proposed scheme against the recent well known probabilistic schemes and our results confirm the superiority of our scheme over existing schemes in terms of key performance metrics, namely Reachability (RE) and Saved Rebroadcast (SR).

In view to reduce accident risks and improve safety on public roads, the vehicular Ad hoc network (VANET) standard was developed to enable inter-vehicular communication and facilitate safety message exchange among the involved nodes. Moreover, a successful message exchange can only be possible if the transmission medium is collision free. Under the Intelligent Transportation System (ITS), the cooperative Awareness messages (CAM) have to be transmitted at the rate of 10 Hz as per standard. To account for congestion management, the Distributed Congestion Control (DCC) mechanism was proposed. However, under higher node density, the DDC becomes inefficient and dramatically contribute to the deterioration of the VANET environment. The present work proposes a Dynamic Broadcast Storm Mitigation Algorithm (DBSMA) which can be used to combat the broadcast storm problem in a Vehicular Network (VN). Results from several simulations confirmed that the DBSMA has a potentiality to conquer the effect of broadcast storm by offering more than 130% improved efficiency against the DCC approach. Other advantage of the DBSMA is that it is very simple to compute and easy to implement.

Vehicular networks aim to provide a communication framework for moving vehicles, road infrastructure and pedestrians. Such kind of networks is the entrance to a new era of services that will make areas such as security and safety, information, transactions, entertainment and sustainability (green transportation) more efficient than they are today, especially in the upcoming era of autonomous vehicles and self-driving cars. However, the severe nature of vehicular environments makes efficient inter-vehicular communication very difficult to achieve. Vehicular Delay-Tolerant Networks (VDTN), as these networks are called, have very sparse, intermittent connections, and the lack of a fixed topology gives rise to one of the main challenges that they face: packet routing. A range of routing algorithms has been proposed in recent years to optimize communication in vehicular networks, and significant progress has been made in the matter but the quest for the optimal performance is still ongoing. In this paper, we explore a deep learning approach to the routing problem in VDTN, proposing a routing architecture and algorithm based on Deep Neural Networks that helps routers make packet forwarding decisions based on the current conditions of its surroundings. In order to assess the performance of the proposed architecture, simulations were run showing important gains in terms of network overhead and hop count with respect to popular routers, while maintaining acceptable packet delivery rates and average delivery delays.

Hybrid routing for safety data with intermittent V2I connectivity

Content-centric wireless networking: A survey