Packet Forwarding Decisions Research Articles

Maximizing SDN resilience to node‐targeted attacks through joint optimization of the primary and backup controllers placements

AbstractIn software defined networks (SDN) packet data switches are configured by a limited number of SDN controllers, which respond to queries for packet forwarding decisions from the switches. To enable optimal control of switches in real time the placement of controllers at network nodes must guarantee that the controller‐to‐controller and switch‐to‐controller communications delays are bounded. Apart from the primary controllers that control the switches in the nominal state, separate backup controllers can be introduced that take over when the primary controllers are unavailable, and whose delay bounds are relaxed. In this paper, we present optimization models to jointly optimize the placement of primary and backup controllers in long‐distance SDN networks, aimed at maximizing the network's resilience to node‐targeted attacks. Applying the models to two well‐known network topologies and running a broad numerical study we show that, when compared with the standard approach of using only primary controllers, the use of backup controllers provides significant resilience gains, in particular in case of tight delay bounds.

On the Potential of Enhancing Delay-Tolerant Routing Protocols via Age of Information

In this paper, we study the potential of using the metric of Age of Information (AoI) for enhancing delay-tolerant routing protocols. The latter have been proposed for alleviating the impact of long roundtrip time in networks operating in harsh environments, e.g., in distributed applications deployed in a desert/sparsely populated area without infrastructure, a space network, etc. Delay-tolerant routing protocols can prevent excessive packet timer expiration, but do not provide any packet delivery time guarantee. Thus, they are unsuitable for time-sensitive applications that are more intensely desired nowadays in the next generation networking applications. By incorporating AoI into the operation of delay-tolerant routing protocols, we aim at devising routing protocols that can cope with both long propagation times and challenges related to time-sensitivity in packet delivery. More specifically, in this work, we modify the operation of a well-known delay-tolerant routing protocol, namely FRESH, to make AoI-based packet forwarding decisions, aiming at achieving specific delay guarantees regarding the end-to-end delivery time. We investigate the advantages and disadvantages of such an approach compared to the traditional FRESH protocol. This work serves as a cornerstone for successfully demonstrating the potential of exploiting AoI in delay-tolerant routing and its applications.

Copy Adaptive Routing Algorithm Based on Network Connectivity in Flying Ad Hoc Networks

The Flying Ad Hoc Network (FANET) is a kind of mobile network which is composed of flying UAVs (Unmanned Aerial Vehicles) as network nodes. With the high node mobility and dynamic topology, data transmission in FANETs is faced with severe challenges, such as unstable communication links and limited resources in the network. Due to the uncertainty of node encounters, data transmission is usually carried out by opportunistic transmission. However, the opportunistic delivery of data using multicopy routing not only consumes a large amount of network resources but also causes too much transmission overhead and low delivery quality. Thus, this paper designs a connectivity-based copy adaptive transmit routing algorithm (CCAT). Considering the network interruptions caused by high-speed node movement, CCAT makes packet forwarding decisions by estimating network connectivity and uses node transmit prediction value as forwarding utility value to control the number of copies of packets. Simulation results show that the delivery rate of CCAT can be improved by about 30% at the peak compared with traditional multicopy routing strategies and the transmission latency of CCAT is minimal.

Yazılım Tanımlı Ağlarda Bağlantı Katmanı Keşif Protokolünün İstismarına Dayalı Topoloji Zehirleme Saldırılarının İncelenmesi

In software defined networks (SDNs), data plane and control plane on the conventional network devices are separated and packet forwarding decisions are taken by the controller in charge of the entire network. The necessity of managing all the network operations not only facilitates control for the controller but also causes some security vulnerabilities and new attack surfaces in SDNs. In this study, Link Layer Discovery Protocol (LLDP), which forms the basis of OpenFlow Discovery Protocol (OFDP) for topology discovery in SDNs, is exploited to poison the topology by adding fabricated links to the controller. Fake LLDP Injection and LLDP replay techniques are used to create fake links on the controller and network access status of end devices are evaluated during attacks. Our findings demonstrate that the Floodlight controller is vulnerable to attacks based on LLDP exploitation and it is possible to create fake links on the controller. Due to the fake links, it is determined that invalid routes are created on controller and despite having other active links, end devices subject to invalid routes lost their access to network. Thus, attacks on the data link layer affect the performance of the network negatively.

Evaluating TCP performance of routing protocols for traffic exchange in street-parked vehicles based fog computing infrastructure

As most vehicles remain parked 95% of its time, this suggests that leveraging the use of On-board Units (OBUs) in parked vehicles would provide communication and computation services to other mobile and fixed nodes for delivery of services such as multimedia streaming, data storage and data processing. The nearby vehicles can form an infrastructure using IEEE 802.11p communication interface, facilitating communication, computation and storage services to the end users. We refer to this as a Vehicular Fog Computing (VFC) infrastructure. In this study, using NS-2 simulator, we investigate how six routing protocols consisting of two proactive routing protocols, Destination Sequence Destination Vector (DSDV) and Fisheye State Routing (FSR); two reactive routing protocols, Ad Hoc On-Demand Distance Vector (AODV) and Dynamic Source Routing (DSR); and two geographic routing protocols, Distance Routing Effect Algorithm for Mobility (DREAM) and Location Aided Routing (LAR) perform when forwarding TCP traffic among the parked vehicles that form a VFC infrastructure in an urban street parking scenario. In order to reflect an urban street parking scenario, we consider a traffic mobility traces that are generated using SUMO in our simulation. To the best of our knowledge, this work is the first effort to understand how vehicle density, vehicle speed and parking duration can influence TCP in an urban street parking scenario when packet forwarding decision is made using proactive, reactive and geographic routing protocols. In our performance evaluation, positive results are observed on the influence of parking duration in parked vehicles as TCP performance in all routing protocols increases with longer parking duration. However, variable speed in parked vehicles and moving vehicles in an urban street parking scenario may not have significant influence on TCP performance, especially in case of reactive and proactive routing protocols. Further, our findings reveal that vehicle density in a VFC infrastructure can noticeably influence TCP performance. Towards the end of the paper, we delineate some important future research issues in order to improve routing performance in a street-parked vehicle based VFC infrastructure.

Efficient Lookup Solutions for Named Data Networks

Named Data Networking (NDN) is afast growing architecture, which is proposed as an alternative to existing IP. NDN allows users to request the data identified by a unique name without any information of the hosting entity. NDN supports in-network caching of contents, multi-path forwarding, and data security. In NDN, packet-forwarding decisions are driven by lookup operations on content name of the NDN packets. An NDN node maintains set of routing tables that aid in forwarding decisions. Forwarding the NDN packets depend on lookup of these NDN tables and performing Longest Prefix Matching (LPM) against these NDN tables. The NDN names are unbounded and of variable length. These features along with large and dynamic NDN tables pose several challenges that include increased memory requirement and delayed lookup operations. To this end, there is a need for an efficient data structure that support fast lookup operations with low memory overhead. Several lookup techniques are proposed in this direction. Traversing trie structures would be slow since every level of trie require a memory access. Hash tables incur additional hash computations on names and suffer from collisions. Bloom filters suffer from false positives and do not support deletions. Improving the performance of these structures can lead to a better lookup solution.This survey paper explores different lookup structures for NDN networks. Performance is measured with respect to lookup rate and memory efficiency.

Towards the Optimal Solution for the Routing Problem in Vehicular Delay Tolerant Networks: A Deep Learning Approach

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.

Packet Forwarding in Common Sink Multi-Domain Wireless Sensor Networks Using Non-Cooperative Game

Multi-domain wireless sensor networks (WSNs) are sensor networks belonging to different network authorities coexisting in the same area. As such networks may be deployed in hostile environments, resource sharing between different sensor networks may necessary to prolong the network lifetime. However, with their limited power supply, sensor nodes may act selfishly by declining to cooperate to conserve their own energy. This paper is focused on how to determine packet forwarding strategies decisions which are beneficial to all networks under constrained resources in multi-domain WSNs. This paper proposes a non-cooperative game algorithm in a packet forwarding game in non-cooperative multi-domain WSNs. The objective is to achieve the best mutual strategy between two multi-domain WSNs. Our results show that the proposed method outperforms the non-game theoretic approach which uses pure cooperative and non-cooperative AODV routing algorithms, in terms of successful packet delivery ratio, network lifetime, and fairness in terms of difference in energy consumption in each domain.

Route or Carry: Motion-Driven Packet Forwarding in Micro Aerial Vehicle Networks

Micro aerial vehicles (MAVs) provide data such as images and videos from an aerial perspective, with data typically transferred to the ground. To establish connectivity in larger areas, a fleet of MAVs may set up an ad-hoc wireless network. Packet forwarding in aerial networks is challenged by unstable link quality and intermittent connectivity caused by MAV movement. We show that signal obstruction by the MAV frame can be alleviated by adapting the MAV platform, even for low-priced MAVs, and the aerial link can be properly characterized by its geographical distance. Based on this link characterization and making use of GPS and inertial sensors on-board of MAVs, we design and implement a motion-driven packet forwarding algorithm. The algorithm unites location-aware end-to-end routing and delay-tolerant forwarding, extended by two predictive heuristics. Given the current location, speed, and orientation of the MAVs, future locations are estimated and used to refine packet forwarding decisions. We study the forwarding algorithm in a field measurement campaign with quadcopters connected over Wi-Fi IEEE 802.11n, complemented by simulation. Our analysis confirms that the proposed algorithm masters intermittent connectivity well, but also discloses inefficiencies of location-aware forwarding. By anticipating motion, such inefficiencies can be counteracted and the forwarding performance can be improved.

Bayesian inference approach for establishing efficient routes in wireless ad-hoc networks

Mobile ad hoc networks (MANETs) are dynamic wireless networks that have no fixed infrastructures and do not require predefined configurations. In this infrastructure-less paradigm, nodes in addition of being hosts, they also act as relays and forward data packets for other nodes in the network. Due to limited resources in MANETs such as bandwidth and power, the performance of the routing protocol plays a significant role. A routing protocol in MATET should not introduce excessive control messages to the network in order to save network bandwidth and nodes power. In this paper, we propose a probabilistic approach based on Bayesian inference to enable efficient routing in MANETs. Nodes in the proposed approach utilize the broadcast nature of the wireless channel to observe the network topology by overhearing wireless transmissions at neighboring nodes in a distributed manner, and learn from these observations when taking packet forwarding decision on the IP network layer. Our simulation results show that our routing approach reduces the number of control message (routing overhead) by a ratio up to 20 % when the network size is 60 nodes, while maintaining similar average route establishment delay as compared to the ad-hoc on demand routing protocol.

The effect of location errors on location based routing protocols in wireless sensor networks

Location-based routing protocols use position information for making packet forwarding decisions, assuming perfect location information. Unlike topological routing algorithms, they do not need to exchange and maintain routing information. They work nearly stateless. However, in practice there could be significant errors in obtaining location estimates.In this paper, the impact of location errors on power consumption of these protocols will be analyzed via developing a mathematical model represents the location errors that may occur in real deployment. Then a simulation of the power consumption of two location-based routing protocols, Geographic Random Forwarding (GeRaf) and Minimum Energy Consumption Forwarding (MECF), is carried out to evaluate the mathematical model.Both the obtained simulation results and the developed mathematical model show that this type of routing protocols suffers from substantial performance degradation in terms of power consumption in presence of location errors.

Multi-criteria Receiver Self-Election Scheme for Optimal Packet Forwarding in Vehicular Ad hoc Networks

In most of the existing geographical forwarding methods of Vehicular Ad hoc NETwork (VANET), a node periodically sends “hello” messages to determine the positional information of its direct neighbors. Each node stores and maintains more or less accurate information of its direct neighbors in a table. However, due to high mobility vehicles and traffic congestion the stored neighbors information is quickly outdated, failure notification increases significantly, and leading sub-optimal path. Furthermore, the transmission of periodic “hello” messages and table maintenance consume resources, which is not suitable for sensitive VANET. In this paper, we propose a geographical forwarding mechanism based on Multi-criteria Receiver Self- Election (MRSE) scheme to find best next hop without sending the periodic “hello” messages and maintaining neighbors information in the table. The selection of best next hop is based on the multi-criteria waiting function. In this function, the four key parameters including link life time, optimal distance from sender to receiver, optimal transmission range, and received power are determined to enable the next candidate node to make packet forwarding decisions. The simulation results show that the MRSE scheme performs up to 22% better in terms of packet delivery ratio as compared to some existing schemes. In terms of average delay, MRSE scheme performs best, with as much as 81% decrease compared to some existing schemes.

Scalable Name Lookup with Adaptive Prefix Bloom Filter for Named Data Networking

In Named Data Networking (NDN), packet forwarding decisions rely upon lookup operations on variable-length hierarchical names instead of fixed-length host addresses. This pivotal feature introduces new challenges in the deployment of NDN at the Internet scale. In this letter, a novel Name Lookup engine with Adaptive Prefix Bloom filter (NLAPB) is conceived, in which each NDN name/prefix is split into B-prefix followed by T-suffix. B-prefix is matched by Bloom filters whereas T-suffix is processed by the small-scale trie. The length of B-prefixes (and T-suffixes) is dynamically throttled based on their popularity in order to accelerate the lookup. Experimental results show that: (i) NLAPB is able to lower the false positive rate with respect to a lookup entirely based on Bloom filters; (ii) it decreases the memory requirements with respect to a trie-based approach; (iii) it reduces processing time with respect to both them.

무선 센서 네트워크에서 향상된 교차 계층 방식의 위치기반 데이터 전달 기법

본 논문에서는 무선 센서 네트워크에서 프로토콜 성능 극대화를 위해서 비동기식 MAC과 라우팅 교차 계층 방식의 향상된 위치 기반 데이터 전송 (Enhanced Geographic Forwarding; EGF) 기법을 제안한다. EGF 기법은 기존의 일반적인 위치 기반 전송 알고리즘과 달리 주기적인 이웃 노드들의 위치 정보 등을 이용하지 않고, 오직 소스와 목적지 노드의 위치 정보와 에너지 비용 정보만을 이용한 최적의 back-off 매핑 메커니즘을 사용하여 데이터를 전송한다. 또한 효율적인 MAC과 라우팅의 교차 계층 방식으로 오버헤드를 최소화하고 데이터 전달 성능을 최적화 하였다. 성능 분석 결과 패킷 전송 성공률, 저전력성 및 데이터 전송 지연에 대해서 향상된 성능을 확인하였다. In this paper, we propose an Enhanced cross-layer Geographic Forwarding (EGF) protocol for wireless sensor networks (WSNs). EGF uses an optimal back-off time to make the packet forwarding decisions using only source and destination's location information and energy cost without information about neighbor nodes' location or the number of one hop neighbor nodes. EGF is also a cross-layer protocol by combining efficient asynchronous MAC and geographic routing protocol. The proposed protocol can find optimal next hop location quickly without broadcasting node's location update and with minimizing overhead. In our performance evaluation, EGF has better performance in terms of packet success ratio, energy efficiency and end-to-end delay in wireless sensor networks.

Hop-by-Hop Routing in Wireless Mesh Networks with Bandwidth Guarantees

Wireless Mesh Network (WMN) has become an important edge network to provide Internet access to remote areas and wireless connections in a metropolitan scale. In this paper, we study the problem of identifying the maximum available bandwidth path, a fundamental issue in supporting quality-of-service in WMNs. Due to interference among links, bandwidth, a well-known bottleneck metric in wired networks, is neither concave nor additive in wireless networks. We propose a new path weight which captures the available path bandwidth information. We formally prove that our hop-by-hop routing protocol based on the new path weight satisfies the consistency and loop-freeness requirements. The consistency property guarantees that each node makes a proper packet forwarding decision, so that a data packet does traverse over the intended path. Our extensive simulation experiments also show that our proposed path weight outperforms existing path metrics in identifying high-throughput paths.

An Improved GPSR Routing Protocol

The rapid movement of Vehicles which results in frequent changes in vehicle position and speed, as well as inaccuracies in predicting driver’s direction at intersections usually lead to wrong packet forwarding decisions in VANET. Consequently, a routing protocol incorporating vehicle density, moving direction and speed into GPSR in making packet forwarding decisions is hereby proposed. Key data structures were designed and MOVE was used to construct typical Grid map urban simulation scenario. The protocol was simulated using NS-2 under the urban simulation scenario and was compared with AODV and GPSR protocols. Our experimental results indicate that the improved GPSR protocol has better performance when packet delivery rate, average end-to-end delay and average throughput are used as the performance metrics, and is better for VANET under the urban simulation scenario.

Backpressure-based routing protocol for DTNs

In this paper we consider an alternative, highly agile In this paper we consider an alternative, highly agile approach called backpressure routing for Delay Tolerant Networks (DTN), in which routing and forwarding decisions are made on a per-packet basis. Using information about queue backlogs, random walk and data packet scheduling nodes can make packet routing and forwarding decisions without the notion of end-to-end routes. To the best of our knowledge, this is the first ever implementation of dynamic backpressure routing in DTNs. Simulation results show that the proposed approach has advantages in terms of DTN networks.

Using Ghosts for Global Topology Knowledge in Space-Parallel Distributed Network Simulations

The authors discuss an approach to federated network simulations that eases the burdens on the simulation developer in creating space-parallel simulations. Previous approaches have had difficulties that arise from the need for global topology knowledge when forwarding simulated packets between federates. In all but the simplest cases, proper packet-forwarding decisions between federates requires routing tables of size O(mn), where m is the number of nodes modeled in a particular federate, and n is the total number of network nodes in the entire topology. Furthermore, the benefits of the well-known NIx-Vector routing approach cannot be fully achieved without global knowledge of the overall topology. The authors overcome these difficulties by using a topology partitioning methodology that uses ghost nodes. They show experimentally that the memory overhead associated with ghosts is minimal relative to the overall memory footprint of the simulation.

Search engine implications for network processor efficiency

Network processors are programmable devices with special architectural features that are optimized to perform packet forwarding decisions. Those decisions are often based on data accessed from various table structures. Access to these structures typically requires one of several search methods, each of which consists of multiple individual memory accesses, leading to significant latency to complete the process. One of the architectural features of network processors is multithreading of each processing element in order to hide the effects of these long latency searches. Hardware search engines can significantly reduce the latency of such searches, and are shown to have a significant impact on the number of threads required in each processing element.

Rapidly switching all-optical packet routing system with optical-label swapping incorporating tunable wavelength conversion and a uniform-loss cyclic frequency AWGR

This letter discusses an experimental demonstration of a rapidly switching all-optical packet routing system with optical-label switching and all-optical label-swapping capabilities. The optical routing system optically extracts the subcarrier optical-label content, compares it against the forwarding table, makes packet forwarding and label-swapping decisions, and forward the packet to the desired output with a newly updated subcarrier optical label. The packet switching fabric included a combination of rapidly tunable wavelength conversion and a uniform-loss cyclic frequency 8/spl times/8 arrayed waveguide grating router. The packet routing system achieved 600-ps switching time and 250-ns forwarding decision time. Accumulated packet bit-error-rate measurements confirm the successful error-free packet routing with all-optical label-swapping.