Routing Resilience Research Articles

Service Risk Evaluation of Telecommunication Core Network: A Perspective of Routing Resilience

Service Risk Evaluation of Telecommunication Core Network: A Perspective of Routing Resilience

Robust Routing Made Easy: Reinforcing Networks Against Non-Benign Faults

With the increasing scale of communication networks, the likelihood of failures grows as well. Since these networks form a critical backbone of our digital society, it is important that they rely on robust routing algorithms which ensure connectivity despite such failures. While most modern communication networks feature robust routing mechanisms, these mechanisms are often fairly complex to design and verify, as they need to account for the effects of failures and rerouting on communication. This paper conceptualizes the design of robust routing mechanisms, with the aim to avoid such complexity. In particular, we showcase simple and generic blackbox transformations that increase resilience of routing against independently distributed failures, which allows to simulate the routing scheme on the original network, even in the presence of non-benign node failures (henceforth called faults). This is attractive as the system specification and routing policy can simply be preserved. We present a scheme for constructing such a reinforced network, given an existing (synchronous) network and a routing scheme. We prove that this algorithm comes with small constant overheads, and only requires a minimal amount of additional node and edge resources; in fact, if the failure probability is smaller than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1/n$</tex-math> </inline-formula> , the algorithm can come without any overhead at all. At the same time, it allows to tolerate a large number of independent random (node) faults, asymptotically almost surely. We complement our analytical results with simulations on different real-world topologies.

Resilience Analysis of Traffic Network under Emergencies: A Case Study of Bus Transit Network

With the continuous development of public transportation, the impact of unexpected events on the operation of bus networks has become increasingly severe due to the growing demand for public transportation and passenger volume. To accurately assess the impact of unexpected events on the operation of bus networks and scientifically evaluate their resilience, this paper proposes a framework for analyzing the resilience of bus networks. With the aim of providing scientific evidence to enhance the reliability of public transportation networks, this framework can be used to determine the resilience of bus networks to unexpected events. The main contributions of this framework include three aspects: 1. Construction of the CRITIC–entropy weighting model for screening and calculating key indicators of the resilience of the bus network; 2. Use of resilience cycle theory to construct a model for analyzing the resilience of bus routes, and design a set of resilience quantification factors to calculate the resilience of bus routes; 3. Use of complex network theory to construct a model for analyzing the resilience of the bus network, by taking the bus route resilience obtained in the second step as the edge weight to calculate the resilience of the bus network. This paper takes the Beijing public transit system as an example and uses real data to verify the accuracy, scientificity, and feasibility of the proposed framework for analyzing the resilience of public transit networks to sudden events. The resilience analysis framework constructed in this paper has improved the existing research on transportation network resilience in theoretical aspects. Furthermore, the results outputted by this framework can provide a decision-making basis for network adjustment and disaster recovery for the management departments of public transportation networks in practical applications.

A Novel Algorithm for AODV to Enhance the Efficiency and Performance of the MANET

Network security and performance are significant topics discussed in academic and Industrial research. Every application depends on the performance and efficiency of the network. Routing protocols and mechanisms play an essential role. AODV routing protocol is considered standard in many aspects, primarily due to the increasing efficiency requirements in various applications. There are different approaches in the literature trying to improve the performance. Some studies considered multiple parameters such as density and mobility of the data nodes. This research study evaluates the two critical parameters that contribute to the overall efficiency and performance of the network – throughput and route resilience. A new version of enhanced AODV is proposed in this paper that uses an iterative approach to check for each parameter and adjust the values accordingly until the required threshold level of efficiency is reached. The solution is explained in different categories pertaining to each network parameter. The proposed algorithm is simulated on a network tool, and the results show that the enhanced version of the routing protocol is promising and can be further extended to introduce new modes for higher efficiency and lower power consumption.

Balancing anonymity and resilience in anonymous communication networks

Anonymous communication networks (ACNs) are intended to protect the metadata privacy during the communication. As typical ACNs, onion mix-nets adopt source routing where the source defines a static path and wraps the message with the public keys of on-path nodes so that the message could be delivered to the destination. However, onion mix-nets lack resilience when the static on-path mixes fail, which could result in message loss, communication failure and even de-anonymization attacks. Therefore, it is desirable to achieve routing resilience in onion mix-nets for persistent routing capability even against node failure. The state-of-the-art solutions mainly adopt mix groups and thus need to share secrets among all the group members, which may cause single point of failure and render massive loss of anonymity.To address the above problem, in this work we design a hybrid routing approach, which essentially embeds the onion mix-net with hop-by-hop routing to achieve desirable routing resilience. Furthermore, we extend our scheme with a threshold setting, and propose T-hybrid routing to mitigate the anonymity loss when group mixes are compromised. Besides, we propose the active defense mechanism to defend replay attacks in the scenario of mix groups. As for experimental evaluations, we conduct a quantitative analysis of the resilience and anonymity for various schemes, and demonstrate that T-hybrid routing can achieve a good balance between resilience and anonymity. In addition, we manage to realize the full T-hybrid routing prototype and test its performance in the cloud hosting environment. The experimental results show that compared with typical onion mix-nets, our T-hybrid routing mechanism only increases about 20%-25% regarding the end-to-end delay, and thus is still practical while with better resilience.

Hybrid Differential Evolution Based Probabilistic Model to Support Quality Aware Best Path Routing Scheme for Mobile Adhoc Networks

The Mobile Ad hoc Networks (MANETs) today represent a new system containing wireless mobile nodes to dynamically and freely organize the topologies of the network without having any communication infrastructure. Owing to the traits such as temporary topology and the absence of a proper centralized authority routing can be a very important issue faced by the ad hoc networks. This multipath routing algorithm has established various paths between the source node and its destination node thus spreading traffic load along various routes. This will be able to alleviate congestion of traffic on a particular path. Thus, the multipath routing algorithms were able to provide route resilience that ensured data transmission reliability. For the purpose of this work, there was a multipath routing scheme which is called the Ad hoc On-demand Multipath Distance Vector Routing (AOMDV) Protocol. This was proposed by means of employing a hybrid Fire Fly (FF) with Differential Evolution (DE) algorithm. This approach was able to achieve better, as well as, reciprocal advantages in a dynamic and hostile network situation. Thus, the proposed scheme of routing was a very powerful method to find effective solutions to MANET routing problems. The proposed method is a well-known probabilistic metaheuristic algorithm to improve the quality aware best path routing protocol. Simulation results indicate that the proposed method FF-DE achieves better performance than AOMDV and FF.

A New Freight Truck Resiliency Indicator with Connected Vehicle Technology

A freight route resiliency indicator is developed in this paper. Basic characteristics of connected vehicle technology (CVT) which can provide advance traffic information is used to develop the indicator. The indicator is sensitive to route changes that might occur due to detour from an unforeseen congestion downstream of the path of the freight truck. The truck can detour at an appropriate exit on its route. This could be done to maximize the route resiliency. Application of the indicator is shown with a 20-mile stretch of I-710 (interstate 710) freeway of the multimodal freight transportation network in the Southern California Region. I-710 is considered as one of the most important truck routes connecting Ports of Long Beach and Los Angeles to other multimodal terminals of California and elsewhere in the United States. It is found that the truck route resilience is maximized if the truck detour occurs at approximately 7th, 6th and 4th exit-ramps downstream from the truck location with probability 0.75, 0.5 and 0.25, respectively. This indicates trucks ability to avoid the downstream congested point with these three probabilities. The resilience indicator developed in this research is extremely useful for resiliency improvements of freight operations in urban regions where congestion occurrence is quite frequent and random

A multilayer graph model of the internet topology

The application of internet maps for developing more effective routing algorithms, security mechanisms and resilience management for both companies and internet service providers can be advanced through their more detailed structural decomposition. This article carefully integrates traceroute datasets from various large-scale measurement campaigns such as iPlane, CAIDA, Carna, DIMES, RIPE Atlas and RIPE IPv6L into internet graphs of a previously unknown large and thus solid scale. It further works with different well-established abstraction levels such as the IP interface, router, point of presence (PoP), autonomous system (AS) and internet service provider (ISP). Finally, by employing a broad diversity of graph measures, this study creates an exhaustive snapshot of the global internet topology. This work creates a baseline for future internet research. Repeated measurements and automated data integration could enable a better understanding of the internet dynamics.

Efficient computation of loop-free alternates

Network failures may lead to serious packet loss and degrade network performance. Therefore, loop-free alternates (LFA) have been widely deployed by many Internet service providers to cope with single network component failure in large Internet backbones. However, the efficiency of LFA has not been sufficiently studied. Some existing methods have extremely large computational overhead, and their computational complexity is linear with the average node degree of the network. The current methods consume a large amount of central processing unit resources, thereby aggravating the burden on the router. To improve the routing resilience without introducing significant extra overhead, this study proposes an incremental alternate computation with negative augmentation algorithm (IAC), which is based on incremental shortest path first algorithm. First, IAC turns the problem of quick implementation of LFA into efficiently calculating the minimum cost of all its neighbors to all other network nodes on the shortest path tree rooted at the computing node. Then, several theorems for calculating the cost are presented and their correctness is validated. Finally, we evaluate IAC through simulations with real-world and generated topologies. Compared with TBFH, DMPA, and DMPA-e, which are algorithms optimized for limited scenarios, IAC finds approximately 50% more available alternates, is more than three times faster, and provides node protection capabilities that TBFH, DMPA, and DMPA-e cannot provide. These advantages make IAC a good candidate for traditional telecommunication networks and emerging complex networks that require failure repair and load balancing in a highly dynamic environment.

AOLSR: hybrid ad hoc routing protocol based on a modified Dijkstra's algorithm

Mobile ad hoc networks (MANETs) are highly vulnerable to both link and node failures due to nodal mobility. The routing resilience against link and/or node failures needs to be enhanced to avoid the degradation of network performance. This can be achieved by multipath routing which uses multiple alternative paths to route the messages via multiple disjoint paths and result in increased bandwidth, fault-tolerance, and security. An optimized link state routing (OLSR) protocol is a proactive routing protocol. An advanced OLSR (AOLSR) protocol is proposed based on a modified Dijkstra's algorithm which enables routing in multiple paths of dense and sparse ne0074work topologies. The routing is based on the energy of nodes and links (implied from the lifetime) and the mobility of the nodes. It is a hybrid ad hoc routing protocol because it combines the proactive and reactive features. It is another form of source routing protocol which allows a sender of a data packet to partially or completely reveal the route the packets take through the network. Two cost functions are introduced to build link-disjoint or node-disjoint paths. Secondary functions, namely path recovery and loop discovery process are involved to manage the topology changes of the network. AOLSR protocol is analyzed and compared with the existing MANET routing protocols namely, dynamic source routing (DSR) and OLSR. Its performance is observed to be satisfactory in terms of average end-to-end delay, packet delivery ratio (PDR), average time in first-in-first-out (FIFO) queue, and throughput.

Design and Evaluation of Techniques for Resilience and Survivability of the Routing Node

This paper presents the final results achieved within the EFIPSANS project on the topic of resilience and survivability in autonomic networks. In particular, the outcome of the investigation of the following issues is presented: adaptive level of recovery, unified architecture for autonomic routing resilience, synergies between autonomic fault-management and resilience in self-managing networks, as well as network resilience through autonomic reroute mechanism enhanced with multi-path node-to-node cooperation. The described ideas are supported by exhaustive descriptions and analyses featuring extensive validation results aimed to prove the applicability of the proposed concepts.

Resilient P2P anonymous routing by using redundancy

One hurdle to using peer-to-peer (P2P) networks as anonymising networks is churn. Node churn makes anonymous paths fragile and short-lived: failures of a relay node disrupt the path, resulting in message loss and communication failures. To make anonymous routing resilient to node failures, we take two steps: 1) we use a simple yet powerful idea based on message redundancy by erasure coding and path redundancy to mask node failures; 2) we base mix choices of a path on node lifetime prediction and choose stable nodes as relay nodes, thereby prolonging single path durability. We present an allocation of erasure-coded message segments among multiple paths that provides a guideline on how to maximise routing resilience upon different node availabilities in real-world systems. Via detailed simulations, we compare routing resilience of our approach and existing anonymity protocols, showing that our approach greatly improves routing resilience while consuming modest bandwidth.

A Cross Layer Routing Protocol for Multihop Cellular Networks

We propose a cross-layer routing protocol for a Code Division Multiple Access (CDMA) Multihop Cellular Network (MCN). In designing the routing protocol for MCN, multiple constraints are imposed on intermediate relay node selection and end-to-end path selection. The constraints on relay nodes include willingness for cooperation, sufficient neighbourhood connectivity and the level of interference offered on the path. Path constraints include end-to-end throughput and end-to-end delay. A facile incentive mechanism is presented to motivate the cooperation between nodes in call forwarding. In addition, we present a route resilience scheme in the event of dynamic call dropping. In particular, a fast neighbour detection scheme for route resilience is proposed. Instead of using periodic HELLO messages as in traditional ad-hoc routing, the proposed neighbour detection scheme adopts an explicit handshake mechanism to reduce neighbour detection latency. We conclude the paper by demonstrating the superior performance of the proposed routing protocol compared with the other well known routing algorithms.

A Resilient P2P Anonymous Routing Approach Employing Collaboration Scheme

Node churn is a hindrance to construction of P2P-based anonymous networks, which makes anonymous paths fragile and results in message losses and communication failures. A collaboration scheme combining Friendly Neighbor-based Incentive (FNI) and Re-encryption mechanism is proposed to deal with the high node churn characteristic of P2P networks. The FNI mechanism encourages peers to forward other peers' messages, and establishes more connections to improve the performance of P2P networks, where only stable and well-behaved nodes can be chosen as relay nodes to improve the durability of anonymous paths. The Re- encryption mechanism is designed to replace those failed relay nodes and achieve routing resilience upon different node availabilities in real-world systems. The results from security analysis and simulation show that the P2P anonymous routing approach employing collaboration scheme significantly improves routing resilience and maintains low latency and modest communication overhead.

The hierarchical cliques interconnection network

The fully connected network possesses extremely good topological, fault-tolerant, and embedding properties. However, due to its high degree, the fully connected network has not been an attractive candidate for building parallel computers. On the other hand, tree-based networks are popular as parallel computer networks, even though they suffer from poor fault-tolerance and embedding properties. The hierarchical cliques interconnection network described in this paper incorporates positive features of the fully connected network and the tree network. In other words, the hierarchical cliques possess such desirable properties as low diameter, low degree, self routing, versatile embedding, good fault-tolerance and strong resilience. Hierarchical cliques can efficiently embed most important networks and possess a scalable, modular structure. Further, by combining hierarchical cliques with fat trees congestion in the upper levels can be alleviated.

Increasing the network performance using multi-path routing mechanism with load balance

Research on multi-path routing protocols to provide improved throughput and route resilience as compared with single-path routing has been explored in details in the context of wired networks. However, multi-path routing mechanisms have not been explored thoroughly in the domain of ad hoc networks. In this paper, we propose a new routing protocol which increases the network throughput. The protocol is a multi-path routing protocol with a load balance policy. The simulations show a significant improvement in terms of connection throughput and end-to-end delay, when compared to single-path routing. The second significant contribution of this paper is a theoretical analysis allowing to compare reactive single-path and multi-path routing with load balance mechanisms in ad hoc networks, in terms of overheads, traffic distribution and connection throughput. The results reveal that multi-path routing (using a load balance policy) provides better performance than reactive single-path routing in terms of congestion and connection throughput, provided that the average route length is smaller than certain upper bounds which are derived and depend on parameters specific to the network. These upper bounds are very crucial because they can be taken into account as constraints in the route discovery mechanism so that the multi-path routing protocol is guaranteed to lead to an increase performance than a simple single-path one. Also, our analysis provide some insight into choosing the right trade-off between increased overheads and better performance. We show in particular that for certain networks, a multi-path routing strategy is not worth considering.

Performance analysis of reactive shortest path and multi-path routing mechanism with load balance

Research on multi-path routing protocols to provide improved throughput and route resilience as compared with single-path routing has been explored in details in the context of wired networks. However, multi-path routing mechanism has not been explored thoroughly in the domain of ad hoc networks. In this paper, we analyze and compare reactive single-path and multi-path routing with load balance mechanisms in ad hoc networks, in terms of overhead, traffic distribution and connection throughput. The results reveals that in comparison with general single-path routing protocol, multi-path routing mechanism creates more overheads but provides better performance in congestion and capacity, provided that the route length is within a certain upper bound which is derivable. The analytical results are further confirmed by simulation.