Congestion control in content centric 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>

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.

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

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.

As a key component in implementing Named Data Networking (NDN), Pending Interest Table (PIT) requires an efficient exact-matching algorithm for a scalable and fast PIT lookup. A Bloom filter (BF) is a memory-efficient data structure for performing exact matching operations. In this paper, three different BF-based PIT architectures are proposed: PIT using functional Bloom filters (FBF-PIT), PIT using counting Bloom filters with return values (rCBF-PIT), and a refined rCBF-PIT with signatures (R-rCBF-PIT). The proposed BF-based PITs incrementally allocate a new BF for storing multiple incoming faces of Interest packets with the same content name. For a Data packet lookup, the proposed PIT architectures simultaneously access every BF structure to find matching faces and delete the faces (i.e., matching Interest packet information). The functional Bloom filter (FBF) used in an FBF-PIT is a key-value data structure that stores values only without keys. However, because the number of non-reusable conflict cells in the FBF increases as the number of stored packets increases in the FBF-PIT, the indeterminable rate increases. To decrease the indeterminable rate, we propose the rCBF-PIT, which uses counting Bloom filters with return values (rCBFs), allowing reusable conflict cells. False positives for Interest packets lead to incorrect deletions that can cause false negatives for incoming Data packets. Because most of the false positives occur in the first BF structure, we finally propose the R-rCBF-PIT, in which the first rCBF is replaced with an rCBF with a signature field. The proposed PITs also provide an aging mechanism using a valid bit and a hit bit for entry expiration. Simulation results show that rCBF-PIT and R-rCBF-PIT both reduce the indeterminable rate by more than 81% compared with FBF-PIT. The results also show that R-rCBF-PIT resolves false negatives caused by incorrect deletions by including the signature fields in the first rCBF.

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.

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.

Resource Pooling concept has been proposed as fair sharing of total network resources among all users sharing a network so that a whole network is treated as a single pooled resource. MPTCP (Multipath TCP) has been proposed as one of the most promising congestion controls which realize the Resource Pooling in the situation that each user can utilize multiple paths. In CCN (Content-Centric Networking), several multipath/multisource congestion control methods have been proposed. A fundamental difference between CCN congestion control and MPTCP where single source is assumed, is multisource and the Resource Pooling in multipath/multisource situation is quite a new research issue. In this paper, we discuss congestion control for CCN from the viewpoint of the Resource Pooling and show that our previously proposed congestion control satisfies the Resource Pooling concept. Our simulation results also show that our proposed congestion control achieves macroscopic fairness among users, which means the Resource Pooling concept is satisfied.

Information-centric networking (ICN) is expected to be a candidate for future internet architecture, and it supports features such as multicast that improves bandwidth utilization and transmission efficiency. However, multicast itself does not provide congestion control. When multiple multicast groups coexist, multicast traffic may exhaust all network resources, and cause network congestion and packet loss. Additionally, traditional IP multicast congestion control mechanisms cannot be directly applied to ICN architecture. Therefore, it is necessary to consider an effective congestion control mechanism for ICN multicast. This paper proposes a single-rate multicast congestion control mechanism, called SRMCC. It supports router-assisted awareness of the network congestion state and congestion control message aggregation. Moreover, the fair shared rate estimation method is innovatively proposed to achieve protocol fairness. Most importantly, it adjusts the rate according to different congestion states indicated by the queue occupancy ratio. By introducing a rate selection factor, it can achieve a balance between packet loss rate and throughput. Experimental results show that our proposal outperforms other mechanisms in throughput, packet loss rate, total bandwidth utilization, and overhead, and achieves protocol fairness and better TCP friendliness.

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

Content Centric Networking (CCN), a future Internet architecture, brings new challenges in maintaining the Quality of Experience (QoE) for video streaming. Because of the universal caching capability of CCN routers, streaming from multiple sources will be common, and switching between content sources might affect QoE by inducing delays and consequently stalls in video playback. This paper proposes a new QoE-aware multi-source video streaming scheme for CCN. First, the content distributions of video files among CCN nodes for different caching methods are studied. Second, an adaptive video streaming with distributed caching (ASDC) algorithm is designed to guarantee QoE during the switching between content sources. The ASDC algorithm considers the delivery of scalable video streams. It automatically adapts the layers in a video stream when there is source switching, based on a QoE model that characterizes the effect of stalling. Experimental results show that the ASDC algorithm outperforms dynamic adaptive streaming over HTTP (DASH) in the CCN platform in terms of the QoE obtained from human subjective tests.

Named Data Networking (NDN) is a new network architecture derived from the success of the Internet. Specifically, NDN addresses and identifies data by naming. Source and destination host addresses are not required for data communication in the NDN because the data is uniquely named instead. In the NDN network, the Forwarding Information Base (FIB) table is responsible for data forwarding, the Pending Interest Table (PIT) is liable for holding the state of data forwarding process, and the Content Store (CS) is used to stock data chunks within the network to optimize the forwarding time to the data without contacting to the content producer. All these data structures consume the memory of devices existing in the Named Data Networking of Things (NDNoT). Accordingly, the size of the FIB, PIT and CS needs to be carefully adjusted in NDNoT environments for performance tuning and Quality of Service (QoS) provisioning. In this study, we explore the issues of FIB sizing on average and maximum occupancy, reliability and maximum delay for constant bit rate (CBR) traffic where each content producer is addressed with a prefix name in the Cooja simulator environment. The results indicate that FIB table size has an impact on the reliability and maximum delay. During the number of records in FIB outpaces the count of nodes in the network, the reliability decreases gradually. Therefore, in constrained NDNoT environment careful allocation of the memory among FIB, PIT and CS becomes an important issue. According to our knowledge so far, this work is the first study showing the effect of FIB table on the performance in an NDNoT environment.

Data communication across the Internet has significantly changed under the pressure of massive content delivery. Content-Centric Networking (CCN) rethinks Internet communication paradigm around named data retrieval, in contrast with the host-to-host transport model of TCP/IP. Content retrieval is natively pull-based driven by user requests, point-to-multipoint and intrinsically coupled with the availability of network storage. By leveraging the key features of CCN transport, in this paper we propose for the first time a congestion control mechanism realizing efficient multipath communication over content-centric networks. Our proposal is based on a Remote Adaptive Active Queue Management (RAAQM) at the receiver that performs a per-route control of bottleneck queues along the paths. We analyze the stability of the proposed solution and assess its performance by means of CCN packet-level simulations under random and optimal route selection.

In this paper, we present our implementation and evaluation of Dynamic Adaptive Streaming over Content centric networking (DASC) which implements MPEG Dynamic Adaptive Streaming over HTTP (DASH) utilizing a Content Centric Networking (CCN) naming scheme to identify content segments in a CCN network. In particular, video segments formatted according to MPEG-DASH are available in different quality levels but instead of HTTP, CCN is used for referencing and delivery. Based on the conditions of the network, the DASC client issues interests for segments achieving the best throughput. Due to segment caching within the network, subsequent requests for the same content can be served quicker. As a result, the quality of the video a user receives progressively improves, effectively overcoming bottlenecks in the network. We present two sets of experiments to evaluate the performance of DASC showing that throughput indeed improves. However, the generated overhead is relatively large and the adaptation strategy used for DASH that assumes an end-to-end connection could be revised for the hop-by-hop architecture of CCN.