Routing Update Research Articles

Prediction models for long-term Internet prefix availability

The Border Gateway Protocol (BGP) maintains inter-domain routing information by announcing and withdrawing IP prefixes. These routing updates can cause prefixes to be unreachable for periods of time, reducing prefix availability observed from different vantage points on the Internet. The observed prefix availability values may not meet the standards promised by Service Level Agreements (SLAs).In this paper, we develop a framework for predicting long-term availability of prefixes, given short-duration prefix information from publicly available BGP routing databases like RouteViews, and prediction models constructed from information about other Internet prefixes. We compare three prediction models and find that machine learning-based prediction methods outperform a baseline model that predicts the future availability of a prefix to be the same as its past availability. Our results show that mean time to failure is the most important attribute for predicting availability. We also quantify how prefix availability is related to prefix length and update frequency. Our prediction models achieve 82% accuracy and 0.7 ranking quality when predicting for a future duration equal to the learning duration. We can also predict for a longer future duration, with graceful performance reduction. Our models allow ISPs to adjust BGP routing policies if predicted availability is low, and are generally useful for cloud computing systems, content distribution networks, P2P, and VoIP applications.

Agent-based load balancing routing for LEO satellite networks

To ensure an intelligent engineering of traffic over entire satellite networks, a distributed routing scheme for low-earth orbit (LEO) satellite networks, agent-based load balancing routing (ALBR), is presented. Two kinds of agents are used. Mobile agents migrate autonomously to explore the path connecting source and destination, to gather inter-satellite link (ISL) cost, identifier and latitude of visited satellites. Meanwhile, stationary agents employ exponential forgetting function to estimate ISL queueing delay, calculate ISL cost using the sum of propagation and queueing delays; evaluate path cost considering satellite geographical position as well as ISL cost, finally update routing items. Through simulations on a Courier-like system, the proposed scheme is shown to achieve better load balancing, and can especially decrease packet loss ratio efficiently, guarantee better throughput and end-to-end delay bound in case of high traffic load. Furthermore, results from the implementation complexity analysis demonstrate that with the aid of agent technology, ALBR has lower on-board computation, storage, signaling requirements than other on-board routing schemes.

Field Division Routing

Multihop communication objectives and constraints impose a set of challenging requirements that create difficult conditions for simultaneous optimization of features such as scalability and performance. Routing in wireless multihop networks represents a crucial component of the overall network efficacy because it is a lower layer that enables the actual functionality of networks. We have developed field division routing (FDR), a distributed and nonhierarchical routing protocol that aims to coordinated addressing of scalability, topology alternations, latency, throughput, energy efficiency, and local storage requirements. FDR is based upon two optimization mechanisms: a reactive and focused diffusion that collects only network topology information directly required formaking localized routing decisions, and a protocol for sharing routing information among neighboring nodes. Routing table initialization and maintenance are scalable in terms of both storage and overhead traffic necessary for building routing tables. FDR provides guaranteed connectivity while providing near-optimal all-node-pairs message delivery. The protocol is also power-efficient to a wide spectrum of topology changes that induce relatively few messages to update routing tables network wide. We analyzed the new routing protocol both theoretically and using simulation.

A link‐lifetime based dynamic source routing protocol (LTDSR) for multimedia over MANETs

This paper proposes a link‐lifetime based dynamic source routing protocol (LTDSR) to support Soft QoS for multimedia over MANETs, with a series of improved routing mechanisms. First, our research has shown that some routes held in the route cache may become invalid as time passes, due to node mobility. In this work, we introduce a path lifetime based route selection strategy by establishing link lifetimes for routes, so that no node may select already broken routes. A route discovery will be initiated before all the routes in the cache are broken. Second, considering that the routing protocol reacts mistakenly to the transmission failures due to congestion, a cross‐layer design framework is explored to establish a shared link‐state table with nodes’ coordinate and velocity vector; on this basis, the link‐state detection mechanism can identify the cause properly when packet loss occurs, and then coordinate with the routing protocol to avoid unnecessary route updating. Our simulation results demonstrate that the LTDSR improves the quality of multimedia playing significantly, in terms of decodable frame ratio, end‐to‐end frame delay and delay jitter. In addition, the route overhead is greatly reduced.

Robust and flexible Internet connectivity for mobile ad hoc networks

An important challenge for the wider adoption of mobile ad hoc network (MANET) technologies is finding ways to efficiently interconnect them with the Internet. However, such interconnections prove difficult due to differences in mobility, addressing and routing between MANETs and existing IP networks. In this paper, we review the existing solutions to interconnect MANETs with the Internet, but find them lacking in robustness and flexibility. For instance, many solutions do not consider the presence of multiple gateways, and in such scenarios they either fail, or are less efficient due to the lack of multi-homing capabilities. A key insight of ours is that the reason for routing failure is usually an interconnection scheme’s inability to express indirection (i.e., a way to enforce routing through a certain gateway on the path toward a destination in the Internet). Another problem concerns state replication where a route update fails to replicate all the routing state needed to forward packets to an Internet gateway. We analyze the above problems and suggest a solution that provides robust and flexible Internet connectivity. With minor adaptions our solution works for any MANET routing protocol, and has support for multiple gateways and multi-homing. Simulations show that, when used in combination with AODV routing, our solution provides up to 20% delivery ratio improvement over one of the main alternatives. A prototype implementation illustrates the feasibility of our solution in the real world.

Load balancing routing for single-layered satellite networks

The varying population density leads to imbalanced utilization rate of satellites. To ensure an intelligent engineering of traffic over satellite networks, a distributed routing scheme for single-layered satellite network, load balancing routing protocol based on mobile agent (LBRP-MA) is proposed. For LBRP-MA, mobile agents explore route by migrating autonomously. Upon arriving at destination, mobile agents migrate back. On each intermediate satellite, mobile agents evaluate path cost considering satellite geographical position as well as inter-satellite link (ISL) cost, and finally take ISL congestion index into account to update routing tables. Through simulations on the Courier-like constellation, the proposed approach is shown to achieve guaranteed end-to-end delay bound and decrease packet loss ratio with better throughput, which is especially suitable for data transferring in case of high traffic load. Moreover, results of the complexity analysis demonstrate that LBRP-MA can have low onboard signaling, storage and computation requirements. Furthermore, issues of LBRP-MA such as ISL congestion index and cost modification factor are discussed.

Rapid self-organised initiation of ad hoc sensor networks close above the percolation threshold

This work shows potentials for rapid self-organisation of sensor networks where nodes collaborate to relay messages to a common data collecting unit (sink node). The study problem is, in the sense of graph theory, to find a shortest path tree spanning a weighted graph. This is a well-studied problem where for example Dijkstra’s algorithm provides a solution for non-negative edge weights. The present contribution shows by simulation examples that simple modifications of known distributed approaches here can provide significant improvements in performance. Phase transition phenomena, which are known to take place in networks close to percolation thresholds, may explain these observations. An initial method, which here serves as reference, assumes the sink node starts organisation of the network (tree) by transmitting a control message advertising its availability for its neighbours. These neighbours then advertise their current cost estimate for routing a message to the sink. A node which in this way receives a message implying an improved route to the sink, advertises its new finding and remembers which neighbouring node the message came from. This activity proceeds until there are no more improvements to advertise to neighbours. The result is a tree network for cost effective transmission of messages to the sink (root). This distributed approach has potential for simple improvements which are of interest when minimisation of storage and communication of network information are a concern. Fast organisation of the network takes place when the number k of connections for each node ( degree) is close above its critical value for global network percolation and at the same time there is a threshold for the nodes to decide to advertise network route updates.

Stochastic Time Evolving Routing Protocol based on Energy and Delay Metrics

In this article, we introduce a Quality of Service (QoS) routing algorithm based on dynamic state-dependent policies. The proposed algorithm uses a bio-inspired approach based on trial/error paradigm to optimize two QoS different criteria: Energy and end-to-end delay. Our proposal, called EDEAR “Energy and Delay Efficient Adaptive Routing”, uses a paradigm based on routes’ exploration. In this phase, we collect information in terms of energy and delay by using continuous learning parameters on the network and update routing table maintained at each node of the network. This phase of exploration has been optimized by proposing a new algorithm based on multipoint relay for energy consumption, thus reducing the overhead generated by the packets exploration. Numerical results obtained with NS simulator for different levels of traffic’s load and mobility show that EDEAR gives better performances compared to traditional approaches.

Adaptive Modeling of Routing Algorithms for Wireless Sensor Networks

Recent years have witnessed a proliferation of routing algorithms for Wireless Sensor Networks (WSNs), hence complicating the choice of the proper algorithm to be used for a given application. Simulation frameworks represent a viable solution to anticipate crucial choices, however existing solutions do not encompass the impact of changes (e.g., route updates, node crashes) on the nodes behavior and vice-versa. This article proposes a novel adaptive modeling approach to master the complexity of the thorough simulation of routing algorithms for WSN. Experimental results are provided showing the effectiveness of the proposed approach at managing changes, and dealing with detailed aspects, during the simulation and comparison of several routing algorithms.

An analytical review for multipath routing in Mobile Ad Hoc Networks

Multipath routing is a new extension to many traditional routing protocols in MANETs. Using multipath routing in MANETs can save energy, reduce frequent routing update, enhance data transmission rates, and increase wireless network bandwidth. This paper introduces an analytical review for multipath routing in MANETs covering its applications, classification, and design issues. A simulation-based analytical evaluation is presented in this review using NS2 for AODV and its multipath extensions namely, AOMDV and MRAODV against two traditional multipath routing protocols namely, DSR and TORA. Simulation results show that traditional multipath protocols outperform the single path version of AODV in terms of packet delivery fraction, routing packets overhead, and throughput while AODV has better performance in terms of average end-to-end delay. AODV extensions outperforms traditional protocols in terms of packet delivery fraction and average end-to-end delay.

Coping with Disruptions

In real-time distribution operations, it is generally assumed that demand process parameters can be precisely estimated. However, this is rarely the case, particularly for products with a short life cycle. Experiments were done to investigate the performance of various strategies for online distribution operations under disruptions caused by surges in demand patterns at a particular facility. Two sets of strategies are considered: (a) optimization-based strategies, in which an off-line optimization problem is formulated and used to update routing and inventory allocation plans, and (b) fixed-tour strategies, in which a priori sets of routes to provide retailers with recourse actions depending on different degrees of real-time information capabilities for controlling the system are used. These are compared against two benchmark policies. Simulation results for two scenarios (high and low inventory holding cost products) show that strategies that use real-time information to update delivery plans systematically outperform strategies in which routes are not modified after the vehicle leaves the depot. The differences tend to be higher in scenarios of products with low inventory holding costs. For replanning strategies, the benefits of en route plan updates are significant, in particular the possibility of diverting the vehicle. In the case of fixed-tour strategies, the possibility of updating tour intervals provides potentially great savings. Replanning strategies systematically outperform fixed-tour strategies.

QoS routing based on mobile agent for LEO satellite IP networks

Current quality of service (QoS) routing schemes for low earth orbit (LEO) satellites IP networks either neglect the varying population density or fail to guarantee end-to-end delay. As a remedy, QoS routing protocol based on mobile agent (QoSRP-MA) is proposed. QoSRP-MA is a source-based routing protocol. Once connection requests arrive, QoS mobile agents are dispatched from ingress satellite to explore routes, which migrate using satellite routing tables. Upon arriving in egress satellite, QoS mobile agents migrate back towards ingress satellite to reserve bandwidth. To construct satellite routing tables, load balancing routing algorithm based on mobile agent (LBRA-MA) is presented. In LBRP-MA, at regular intervals mobile agents launched on all satellites migrate autonomously to evaluate path cost and update routing tables. Moreover, path cost between source and destination is evaluated considering satellite geographical position as well as inter-satellite link (ISL) cost. Furthermore, ISL congestion index is considered to update routing table. Through simulations on a Courier-like constellation, it shows that QoSRP-MA can achieve guaranteed end-to-end delay bound with higher throughput, lower connection failing ratio and signaling overhead compared to high performance satellite routing (HPSR) scheme.

Autonomic MANET Routing Protocols

In Mobile Ad hoc Networks (MANETs), timers have been used widely to maintain routing (state) information. The use of fixed-interval timers is simple to implement but, in practise, may be difficult to configure in dynamic operational environments, and so may give reduced performance in the presence of frequent topology changes. This paper proposes a self-tuning timer approach within a simple control system for MANET routing protocols with the aim of allowing dynamic, autonomic, re-calibration of routing update frequencies. A novel dynamic timer algorithm is presented to automatically tune routing performance by adapting timer intervals to network conditions. Our simulation results have shown that, compared to the default fixed timer approach, the proposed algorithm could effectively improve routing throughput without manual configuration.

Energy optimization for proactive unicast route maintenance in MANETs under end-to-end reliability requirements

Many time-critical applications for Mobile Ad hoc NETworks (MANETs), such as the military applications and disaster response, call for proactive link and route maintenance to ensure low latency for reliable data delivery. The goal of this paper is to minimize the energy overhead due to the high control traffic caused by the periodic route and link maintenance operations in the proactive routing protocols for MANETs. This paper — (i) categorizes the proactive protocols based on the maintenance operations performed; (ii) derives analytical estimates of the optimum route and link update periods for the different protocol classes by considering (a) the data traffic intensity, (b) link dynamics, (c) target reliability, measured in terms of Packet Delivery Ratio (PDR), and (d) the network size; and (iii) proposes a network layer dynamic Optimization of Periodic Timers (OPT) method based on the analytical estimates to locally vary the update periods in the distributed nodes. Simulation results show that DSDV-Opt, a variation of DSDV protocol using OPT, — (i) achieves the target PDR with 98.7% accuracy while minimizing the overhead energy; (ii) improves the protocol scalability; and (iii) reduces the control traffic for low data traffic intensity.

Routing scalability in multi-domain DWDM networks

This paper studies routing scalability in multi-domain DWDM networks. Although inter-domain provisioning has been well studied for packet/cell-switching networks, the wavelength dimension (along with wavelength conversion) poses many challenges in multi-domain DWDM settings. To address these concerns a detailed GMPLS-based hierarchical routing framework is proposed for multi-domain DWDM networks with wavelength conversion. This solution uses mesh topology abstraction schemes to hide domain-internal state. However related inter-domain routing loads can be significant here, growing by the square of the number of border nodes. To address these scalability limitations, improved inter-domain routing update strategies are also proposed and the associated performance of inter-domain lightpath RWA and signaling schemes studied.

Reliable energy-efficient routing with novel route update in wireless sensor networks

In this paper we introduce a novel energy-aware routing protocol REPU (reliable, efficient with path update), which provides reliability and energy efficiency in data delivery. REPU utilizes the residual energy available in the nodes and the received signal strength of the nodes to identify the best possible route to the destination. Reliability is achieved by selecting a number of intermediate nodes as waypoints and the route is divided into smaller segments by the waypoints. One distinct advantage of this model is that when a node on the route moves out or fails, instead of discarding the whole original route, only the two waypoint nodes of the broken segment are used to find a new path. REPU outperforms traditional schemes by establishing an energy-efficient path and also takes care of efficient route maintenance. Simulation results show that this routing scheme achieves much higher performance than the classical routing protocols, even in the presence of high node density, and overcomes simultaneous packet forwarding.

모바일 애드 혹 네트워크(Mobile Ad-hoc Networks)에서 홉 카운트 변조 공격으로부터의 라우팅 테이블 보안

모바일 애드 혹 네트워크 (Mobile Ad-hoc Networks)에서 AODV 라우팅 알고리즘은 소스 노드에서 목적지 노드까지의 경로를 확보하기 위하여 RREQ(Route Request) 패킷을 전체 네트워크에 브로드캐스트 한다. 이 과정에서 브로드캐스트 되는 RREQ 패킷을 악의적인 목적을 가진 노드들이 수신했을 경우 RREQ 패킷의 필드를 변조하는 공격이 가능하게 된다. 본 논문에서는 RREQ 패킷의 홉 카운트(Hop Count) 필드를 변조함으로써 라우팅 테이블에 대한 공격 시도를 차단하는 방법을 제안한다. 소스 노드에서 목적지 노드까지 경로 설정 시, 홉 카운트 대신 지연(Delay)을 이용하여 최단 경로를 결정하며, 이로 인해 홉 카운트 변조를 통한 공격으로부터 라우팅 테이블을 보호한다. 성능 평가를 위한 시뮬레이션은 NS-2를 이용하였으며, 홉 카운트 변조를 통한 공격이 정상 트래픽에 미치는 영향을 분석하였고, 제안하는 메커니즘을 통해 안전한 데이터의 전송을 확인하였다. The AODV routing algorithm in a mobile ad-hoc networks broadcasts RREQ packet to find a route from a source to a destination. An attacker node may intercept a RREQ packet and attack by falsifying a field in that packet. In this paper, we propose a simply modified method which can protect a routing table from an attack to falsify the hop count field in the RREQ packet. When establishing a connection between a source and a destination, we update routing table of each node on the connection based on minimum delay instead of minimum hop count. By doing this, we can protect routing table from an attack to falsify a hop count Our simulation is implemented in Network Simulator(NS-2). We analyze how an attacker affects the mobile ad-hoc networks. The result of the simulation shows that the proposed mechanism transfers a data securely.

Stability of virtual network topology control for overlay routing services

Overlay networks achieve new functionality and enhance network performance by enabling control of routing at the application layer. However, this approach results in degradations of underlying networks due to the selfish behavior of overlay networks. We discuss the stability of virtual network topology (VNT) control under overlay networks that perform dynamic routing updates. We find that the dynamics of routing on overlay networks cause a high fluctuation in the traffic demand matrix, which leads to significant VNT control instability. To overcome this instability, we introduce three extensions, hysteresis, two-state utilization hysteresis, and filtering, to VNT control. Simulation results show that the hysteresis mechanism improves network stability, but cannot always improve network performance. We therefore extend the hysteresis mechanism and show that it improves both network stability and performance. However, this extension requires a lot of time for the VNT to converge to a stable state. To achieve fast convergence, we use a filtering method for VNT control. Through simulations, we prove that our methods achieve stability against overlay routing without loss of adaptability for changes in traffic demand.

The internet diary

This is the first in a new series of reports on selected activities from the Internet Engineering and Research Task Forces, IETF and IRTF. This issue focuses on IP mobility, routing in mobile ad-hoc networks, routing scalability, and transition from IP version 4 to version 6. Principal in IP mobility is the impending publication of the NETLMM working group's Proxy Mobile IPv6 protocol, as well as the creation of the new MEXT working group for maintenance and extension of (non-proxy) Mobile-IPv6-based protocols. Two second-generation routing protocols for ad-hoc networks are being completed in the MANET working group. Engineering of IP auto-configuration mechanisms for ad-hoc networks has stalled in the Autoconf working group due to the inappropriateness of the subnet-oriented IP addressing model in less structured mobile ad-hoc networks. Routing scalability is the main focus of the Routing research group from IRTF. The group is set to develop a recommendation on how to mitigate the critical growth in routing table size and update frequency. The v6ops working group is redesigning its IPv4/IPv6 protocol translator to provide operators with an urgently needed tool for interworking between IP versions.

Controlling IP Spoofing through Interdomain Packet Filters

The distributed denial-of-service (DDoS) attack is a serious threat to the legitimate use of the Internet. Prevention mechanisms are thwarted by the ability of attackers to forge or spoof the source addresses in IP packets. By employing IP spoofing, attackers can evade detection and put a substantial burden on the destination network for policing attack packets. In this paper, we propose an interdomain packet filter (IDPF) architecture that can mitigate the level of IP spoofing on the Internet. A key feature of our scheme is that it does not require global routing information. IDPFs are constructed from the information implicit in border gateway protocol (BGP) route updates and are deployed in network border routers. We establish the conditions under which the IDPF framework correctly works in that it does not discard packets with valid source addresses. Based on extensive simulation studies, we show that, even with partial deployment on the Internet, IDPFs can proactively limit the spoofing capability of attackers. In addition, they can help localize the origin of an attack packet to a small number of candidate networks.