Routing Update Research Articles

그룹 이동성을 가지는 무선 네트워크에서 이동 적응적인 라우팅 업데이트 구조

다수의 노드들이 유사한 이동 특성을 보이는 그룹 이동성을 고려하였을 때, 동일 그룹에 속한 노드간의 상대 속도는 작기 때문에 그룹 내 라우팅 업데이트 주기를 길게 설정하여 라우팅 오버헤드를 최소화하는 것이 가능하지만, 수집된 정보의 정확성이 저하되기 때문에 상대 속도가 큰 그룹 간의 패킷 전송 성공률이 감소된다. 그룹 간의 라우팅 오버헤드를 패킷 전송 성공률의 저하 없이 감소시키기 위해 이동 적응적인 라우팅 업데이트 구조가 본 논문에서 제안된다. 제안하는 알고리즘은 각 그룹 단위로 이동성을 예측을 하고 이를 통해 라우팅 업데이트 주기를 유동적으로 조절하여 라우팅 오버헤드를 감소시킨다. 또한 적절한 인접 그룹을 중계(relay) 그룹으로 설정하여, 추후 이동성에 의해 두 그룹간의 직접적인 연결이 단절되더라도 중계 그룹을 통해 통신이 원활이 유지될 수 있도록 지원함으로써 오버헤드가 감소하고 패킷 전송 성공률이 높아지게 된다. With group mobility, minimizing routing overhead among intra-group nodes can be achieved by making longer the routing update period, which may lead to degradation of inter-group's routing performance and consequently the inter-group packet delivery success ratio will be decreased. To reduce the inter-group routing overhead without lowering the inter-group packet delivery success ratio, a mobility-adaptive routing update(MARU) scheme is proposed in this paper. Main idea of the proposed scheme is group-based mobility prediction and updating routing paths by selecting intermediate common relay groups.

Catching popular prefixes at AS border routers with a prediction based method

Modern Internet routers require powerful forwarding facilities to cope with extremely high rate Forwarding Information Base (FIB) lookups. In general, the FIB is constrained to a small highly efficient but expensive memory. Unfortunately, the BGP route table (RIB) keeps increasing, and this subsequently results in severe FIB inflation at BGP routers. What if we only load a small portion of the RIB into the FIB? Recently the route caching mechanism has been revisited. With such a route caching mechanism, the optimal method is to load in a FIB with popular prefixes which contribute major traffic loads. We propose a prediction based method to catch those popular prefixes with a limited cache size. In this paper, the dynamics of popular prefixes has been studied based on real traffic traces from different ISPs. On applying a GM(1,1) model which is widely applied in grey system control and prediction, we propose a traffic prediction-based route caching method which attempts to bias the cache dump strategy with a range of history to ameliorate the effects of bursts from non-popular prefixes. We also suggest applying FIB aggregation techniques, e.g. Optimal Routing Table Constructor (ORTC) algorithm, to suppress the number of non-popular sub-prefixes of the popular prefixes on route updates. The evaluation of our method is based on simulation over real traffic traces. The simulation shows our prediction-based cache replacement strategy outperforms other cache strategies and matches Internet traffic dynamics very well.

Performance evaluation of anycast-based micro-mobility management

The common goal of micro-mobility proposals is to minimise delay, signalling load and packet loss during handover. Most of the existing mobility management protocols rely on a hierarchical architecture, to reduce routing update latency. The main drawbacks of hierarchical architectures are their vulnerability to failures at higher levels of hierarchy and the increasing load of network nodes at these levels. The anycast-based micro-mobility protocol is not sensitive to node or link failure, since it contains no centralised database and the routing information is distributed among network nodes. Our solution is highly decentralised and uses an enhanced IP-based mobility detection method. The proposed scheme is independent of the radio layer and does not introduce any extra signalling load on the wireless interface. The signalling load introduced by the routing information updates is proportional to the number and speed of mobile nodes in the network.

An Optimized AOMDV Routing Algorithm Based on Self-Adaptive Node Speed in Wireless Sensor Network

Focusing on the requirement the validity of standby route under high speed movement scene of wireless sensor network, an optimized AOMDV routing protocol based on self-adaptive node speed (ANS-AOMDV) is proposed. In ANS-AOMDV, the update rule based on self-adaptive node speed is also adopted for standby route in order to solve the standby route invalidation problem existing in route update method based on signal strength. The simulation results prove the performance parameters such as routing consume and routing reconstruction times are improved evidently under the high speed movement scene in ANS-AOMDV.

A New Loop-Free Proactive Source Routing Scheme for Opportunistic Data Forwarding in Wireless Networks

Opportunistic data forwarding (ODF) has drawn much attention in wireless networking research in recent years. The effectiveness of ODF in wireless networks is heavily depended on the choice of proper routing protocols which can provide effective source routing services. In this paper, we propose a new routing protocol named PSR for ODF in mobile ad-hoc networks. PSR is featured by proactive source routing, loop-free, and extremely small routing overhead. Compared to existing routing protocols, there is no need to timestamp routing updates in PSR and the update messages are harmoniously integrated into the tree structure, so that the overhead can be significantly reduced.

Performance of Mobility Models for Routing Protocol in Wireless Ad-hoc Networks

Nowadays Mobile Ad Hoc Networks (MANETs) are a very popular and emerging technology in the world. MANETs helps mobile nodes to communicate with each other anywhere without using infrastructure. For this purpose we need good routing protocols to establish the network between nodes because mobile nodes can change their topology very fast. Mobile node movements are very important features of the routing protocol. They can have a direct effect on the network performance. In this paper, we are going to discuss random walk and random waypoint mobility models and their effects on routing parameters. Previously, mobility models were used to evaluate network performance under the different routing protocols. Therefore, the network performance will be strongly modeled by the nature of the mobility pattern. The routing protocols must rearrange the changes of accurate routes within the order. Thus, the overheads of traffic routing updates are significantly high. For specific network protocols or applications, these mobility patterns have different impacts.

Packet Loss Reduction During Rerouting

When a network failure is detected by an IP router, its routing table is updated for all affected routing entries. The packet loss resulting from this event depends on the network traffic associated with the updated routing table entries. In this paper, we model this process, define packet loss minimization heuristics relying on network traffic prediction models, and show by simulation that the resulting packet loss can be reduced compared to the default routing table update process.

Securing AODV Routing Protocol in MANET Based on Cryptographic Authentication Mechanism

In mobile ad hoc wireless network (MANET), secure communication is more challenging task due to its fundamental characteristics like infrastructure less, wireless link, distributed cooperation, dynamic topology, lack of association, resource constrained and physical vulnerability of node. In MANET, attacks can be broadly classified in two categories: routing attacks and data forwarding attacks. Any action not following rules of routing protocols belongs to routing attacks. The main objective of routing attacks to mislead or disrupt normal functioning of network by advertising false routing updates. On the other hand data forwarding attacks include actions such as modification or dropping of data packet that does not disrupt routing protocol. In this thesis work, we proposed a method to secure ad hoc on-demand distance vector (AODV) routing protocol. The proposed method provides security for routing packets and can efficiently prevent the attacks such as black hole, modifying routing information and impersonation. The proposed method uses hashed message authentication code (HMAC) function which provides fast message verification and sender as well as intermediate nodes authentication. We simulate and compare the proposed method with original AODV and secure AODV (SAODV) protocol using network simulator tool (NS2). Simulation result shows that proposed method minimizes the time delay and network routing load involved in computation and verification of security fields during route discovery process and performs better than the original AODV protocol in the presence of malicious nodes performing black hole attack.

Two-level tries: A general acceleration structure for parallel routing table accesses

The stringent performance requirement for the high efficiency of routing protocols on the Internet can be satisfied by exploiting the threaded border gateway protocol (TBGP) on multi- cores, but the state-of-the-art TBGP performance is restricted by a mass of contentions when racing to access the routing table. To this end, the highly-efficient parallel access approach appears to be a promising solution to achieve ultra-high route processing speed. This study proposes a general routing table structure consisting of two-level tries for fast parallel access, and it presents a heuristic-based divide-and-recombine algorithm to solve a mass of contentions, thereby accelerating the parallel route updates of multi-threading and boosting the TBGP performance. As a projected TBGP, this study also modifies the table operations such as insert and lookup, and validates their correctness according to the behaviors of the traditional routing table. Our evaluations on a dual quad-core Xeon server show that the parallel access contentions decrease sharply by 92.5% versus the traditional routing table, and the maximal update time of a thread is reduced by 56.8% on average with little overhead. The convergence time of update messages are improved by 49.7%.

QoS Parameter Analysis on AODV and DSDV Protocols in a Wireless Network

Wireless networks are characterized by a lack of infrastructure, and by a random and quickly changing network topology; thus the need for a robust dynamic routing protocol that can accommodate such an environment. To improve the packet delivery ratio of Destination-Sequenced Distance Vector (DSDV) routing protocol in mobile ad hoc networks with high mobility, a message exchange scheme for its invalid route reconstruction is being used. Two protocols AODV and DSDV simulated using NS-2 package and were compared in terms throughput, end to end delay and packet faction delivery varying number of nodes, speed and time. Simulation results show that DSDV compared with AODV, DSDV routing protocol consumes more bandwidth, because of the frequent broadcasting of routing updates. While the AODV is better than DSDV as it doesn’t maintain any routing tables at nodes which results in less overhead and more bandwidth. AODV perform better under high mobility simulations than DSDV. High mobility results in frequent link failures and the overhead involved in updating all the nodes with the new routing information as in DSDV is much more than that involved AODV, where the routes are created as and when required. AODV use on -demand route discovery, but with different routing mechanics. AODV uses routing tables, one route per destination, and destination sequence numbers,

Using novel distributed heuristics on hexagonal connected dominating sets to model routing dissemination

Network-centric Future Force must support a large and diverse group of communication nodes. Despite the fact that there is ample scope for network design in networks such as Future Combat Systems (FCS) and Warfighter Information Network-Tactical (WIN-T), there are important performance limits when network conditions become more extreme (highly mobile or dense). In previous work, we modeled and analyzed the expected user performance of a number of novel approaches to flooding link state routing information in wireless ad hoc networks for routing update. We compared routing dissemination schemes such as this of Flat Flooding and Multi-Point Relays (MPRs), with our own variations on Connected Dominating Sets (CDSs), assuming other parts of the routing protocol were taken from standard Link State Routing protocol (OLSR) or Open Shortest Path First protocol (OSPF), widely used in the Internet and WIN-T. Although the existing literature provides a variety of models for Flat Flooding and MPRs, it lacks similar analytical work for relays placement under a CDS approach. Towards the latter, we selected one representative from our novel CDS-based models--the CDS Hexagon, as it provides the lowest routing overhead among other properties. Our analysis demonstrates the difference in the impact of conditions on key performance metrics, such as this of network density on routing overhead as well as a tradeoff between routing overhead and routing stretch. We then advance CDS-HEX dissemination from the limited-scope centralized scenarios with strictly symmetrical relay placement to dynamic scenarios with totally random relay placement. We use novel heuristics to adapt the analytical CDS-HEX to dynamic environments. We show that: (a) although the distributed scheme naturally operates sub-optimally compared to its centralized ancestor, it is still superior to MPRs over certain metrics of interest, (b) the set-up overhead of CDS-HEX is not significantly higher than this of MPRs, while at the same time, the steady state overhead of CDS-HEX appears adequately lower than this of MPR, and (c) all the closed analytical formulae and asymptotic results derived in our previous analysis are verified by our simulations which also provide additional insight on metrics that cannot be analytically measured. Our scheme on one hand is not overly expensive to set up despite the more complex generation process, and on the other hand has a superior performance for the majority of network conditions, and close to the optimal one anticipated by the corresponding centralized model.

Cellular data network infrastructure characterization and implication on mobile content placement

Despite the tremendous growth in the cellular data network usage due to the popularity of smartphones, so far there is rather limited understanding of the network infrastructure of various cellular carriers. Understanding the infrastructure characteristics such as the network topology, routing design, address allocation, and DNS service configuration is essential for predicting, diagnosing, and improving cellular network services, as well as for delivering content to the growing population of mobile wireless users. In this work, we propose a novel approach for discovering cellular infrastructure by intelligently combining several data sources, i.e., server logs from a popular location search application, active measurements results collected from smartphone users, DNS request logs from a DNS authoritative server, and publicly available routing updates. We perform the first comprehensive analysis to characterize the cellular data network infrastructure of four major cellular carriers within the U.S. in our study.

Intelligent routing information protocol using full triggered update mechanism

The heartbeat of network is the routing services which are available upon the execution of protocols. Many routing protocols emerge over one another to strive for betterment in performing the main function of routing the packets to destination efficiently. Despite the superiority of the new protocols in certain feature, the old routing information protocol (RIP) is still widely used due to its simplicity. RIP updates its routing table on a constant interval period by checking the existence of neighbor nodes and changes on the path availability. This mechanism, however, has some drawbacks of bandwidth consumption and higher routing overhead generation. This paper studies the affect of periodic update mechanism on the consumption of bandwidth and proposes a new routing update mechanism. Our technique eliminates the periodic update mechanism in RIP and replaces it with full triggered update by topology change detection mechanism (TRIP). The proposed mechanism triggers the update when topology change is detected. We tested our proposed mechanism in Network Simulator 2 (Ns 2) simulations. The results show that TRIP consumes less bandwidth and sends less routing packets by 70% than RIP. This work contributes significantly to small network as bandwidth is obviously limited. Key words: Distance vector routing, routing information protocol (RIP), triggered update, periodic update, link failure detection.

Link weight assignment and loop-free routing table update for link state routing protocols in energy-aware internet

In order to lessen the greenhouse effects and diminish environmental pollution, reducing energy usage is important in designing next generation networks. Shutting down the network devices that carry light load and redirecting their traffic flows to other routes is the most common way to reduce network energy consumption. Since traffic demands among node pairs vary in different time periods, an energy efficient network has to dynamically determine the optimal active links to adapt itself to network traffic changes. However, in current IP networks, shutting down and/or turning on links would trigger link state routing protocols to reconverge to a new topology. Since the convergence time would take tens of seconds, routing table inconsistencies among routers would result in network disconnection and even worse, generating traffic loops during the convergence interval. Removing routing images inconsistent among routers to prevent loops is a critical issue in energy efficient network and this issue is still not considered in the green network design yet. The contribution of the paper is presented in two parts. First, we propose a comprehensive approach to determine a network topology and a link metric for each time period. Traffic engineering is considered in our design such that flows going on the energy-aware network are within a predetermined percentage of the link capacity such that no congestion occurs in a statistical manner. Second, to avoid transient loops during time period changes, we propose a Distributed Loop-free Routing Update (DLRU) scheme to determine the correct sequence for updating the routing table. A scrupulous proof was also presented to ensure the loop-free property of the DLRU. In this paper, we formulate an integer linear programming to determine this multi-topology and link weight assignment problem. Due to its NP-hard property, we propose an efficient algorithm, termed Lagrangian Relaxation and Harmonic Series (LR&HS) heuristic. Numerical results demonstrate that the proposed LRHS approach outperforms the other approaches on several benchmark networks and random networks by providing up to 35%–50% additional energy saving in our experimental cases.

Toward a practical approach for BGP stability with root cause check

The instability issues of the Border Gateway Protocol (BGP), such as route oscillations and path explorations, can decrease the performance of packet forwarding and place heavy workload on routers. While BGP instability has been extensively studied, existing solutions mainly solve individual instances of BGP instability. Thus, with the existing solutions, the route selection processes of ASes or routers may not realize the actual root cause of BGP instability and hence cannot effectively solve the BGP instability problem. In this paper, we propose a simple, integrated solution called stable BGP (stableBGP) that practically solve a general class of BGP instability issues, including route oscillations and path explorations. stableBGP seeks to adapt the route selection process to best address the root cause of route changes so that the route selection process can quickly stabilize. We formally prove that stableBGP can achieve BGP stability. Extensive simulation results show that in the link failure scenario, stableBGP significantly reduces the number of route changes, the convergence time, and the number of route update messages when compared to prior solutions. We also analyze the performance of stableBGP when it is partially deployed. Our work provides insights into developing a practical solution that addresses the BGP instability problem.

An empirical study of behavioral characteristics of spammers: Findings and implications

In this paper we present a detailed study of the behavioral characteristics of spammers based on a two-month email trace collected at a large US university campus network. We analyze the behavioral characteristics of spammers that are critical to spam control, including the distributions of message senders, spam and non-spam messages by spam ratios; the statistics of spam messages from different spammers; the spam arrival patterns across the IP address space; and the active duration of spammers, among others. In addition, we also formally confirm an informal observation that spammers may hijack network prefixes in sending spam messages, by correlating the arrivals of spam messages with the BGP route updates of the corresponding networks. In this paper we present the detailed results of the measurement study; in addition, we also discuss the implications of the findings for the (content-independent) anti-spam efforts.

Update Chain-based Approach for Checking Route Oscillation of BGP

This paper presents a novel approach for checking route oscillation of border gateway protocol (BGP) quickly, by which the privacy of routing policies of autonomous system (AS) can be respected. Firstly, route update chain tag (RUCT) is constructed to track the forwarding of update report, and local routing library is made to record the changing history of update report. Then route oscillation can be identified by analyzing correlative state of RUCT and local routing library. The characteristic of this approach is that an arbitrary AS can check route oscillation alone only by sharing its network ID, which greatly respects the privacy of routing policies for each AS. This paper shows that both looping in RUCT and consecutive positive-negative report in local record are sufficient conditions for route oscillation. Comparative experiments demonstrate the availability and efficiency of the proposed approach.

A Self-Adaptive Model of Two-Level for Dynamic Peer-to-Peer Networks

The present thesis puts forward a hierarchical P2P model: self-adaptive P2P model of two-level. Super peers compose a self-adaptive DHT network on the top layer, and lower ordinary peers take super peer in the same group as their center server to form a cluster. Data are stored in ordinary peers and super peers hold indices of data and answer for request from ordinary peers. When super peer join or leave, it does not maintain consistency of entire network’s logic topology but only update routing table of its predecessor and successor, besides, super peers update their routing table cache when they transmit messages. The ordinary peers keep backup of super peer for system restore when super peer fails. System can optimize network structure by select peers with high capacity to be super peer and restrict amount of peers in each group.

Network Layer Attacks and Defense Mechanisms in MANETS- A Survey

The foremost concerned security issue in mobile ad hoc networks is to protect the network layer from malicious attacks, thereby identifying and preventing malicious nodes. A unified security solution is in very much need for such networks to protect both route and data forwarding operations in the network layer. Without any appropriate security solution, the malicious nodes in the network can readily act to function as routers. This will solely disturb the network operation from correct delivering of the packets, like the malicious nodes can give stale routing updates or drop all the packets passing through them. In this paper a study that will through light on such attacks in MANETS is presented. The paper also focuses on different security aspects of network layer and discusses the effect of the attacks in detail through a survey of approaches used for security purpose.

Trajectory Estimation for Wireless Mobile Networks Using Polynomial Regression

Trajectory Estimation for Wireless Mobile Networks Using Polynomial RegressionArbitrary and random motion of mobile ad hoc network nodes while communicating results in frequent topology changes and multiple disconnections of links. This dynamic environment challenges the routing of data from the source to the destination and imposes the need for prediction models to track these changes, and then determine future topology of the network. The prediction of network mobility into the future will reduce the frequency of location updates for geographical routing protocols. Moreover it will reduce route request delay and the frequency of route updates in topology based protocols. This paper proposes a predictive model called polynomial regression trajectory estimation. This model is based on the regular behavior of nodes and uses polynomial regression to allow each mobile node to estimate its future locations as a function of time. The estimated locations will be disseminated to the network so that nodes can use them to estimate the future topologies of the entire network. The efficiency of the proposed model has been evaluated by MATLAB simulation.