Along & Across algorithm for routing events and queries in wireless sensor networks

published_or_final_versio

Traffic distribution over equal-cost-multi-paths

To effectively manage the traffic distribution inside a network, traffic splitting is needed for load sharing over a set of equal-cost-multi-paths (ECMPs). In this paper, a new traffic splitting algorithm, called Table-based Hashing with Reassignments (THR), is proposed. Based on the load sharing statistics collected, THR selectively reassigns some active flows from the over-utilized paths to under-utilized paths. The reassignment process takes place in such a way that the packet out-of-order problem is minimized. As compared with the existing traffic splitting algorithms, THR provides close-to-optimal load balancing performance, less than 2% of packets arrived out-of-order, and a very small end-to-end packet delay performance. Although additional traffic monitoring function is needed by THR, we show that the extra complexity incurred is marginal.published_or_final_versio

Time-efficient algorithms for BGP route configuration

Based on the concept of most popular prefix first, two efficient algorithms for BGP route configuration are proposed. The first algorithm MPPF_SES is designed for solving the single egress selection (SES) problem, and the second algorithm MPPF_MES is for multiple egress selection (MES). MPPF_MES has two variants, one aims at minimizing the total amount of resources consumed for carrying the transit traffic, and the other tries to minimize the egress link capacity required. Compared with the existing algorithms, a comparable performance in terms of network resources consumed can be obtained. In case of SES, our MPPF_SES can carry a given traffic load with much lower egress link capacity requirement. In case of MES, our MPPF_MES tends to provide a more stable performance. Last but not the least, our proposed algorithms have a much lower time complexity than the existing approach.published_or_final_versio

Time-efficient algorithms for BGP route configuration

Based on the concept of most popular prefix first, two efficient algorithms for BGP route configuration are proposed. The first algorithm MPPF_SES is designed for solving the single egress selection (SES) problem, and the second algorithm MPPF_MES is for multiple egress selection (MES). MPPF_MES has two variants, one aims at minimizing the total amount of resources consumed for carrying the transit traffic, and the other tries to minimize the egress link capacity required. Compared with the existing algorithms, a comparable performance in terms of network resources consumed can be obtained. In case of SES, our MPPF_SES can carry a given traffic load with much lower egress link capacity requirement. In case of MES, our MPPF_MES tends to provide a more stable performance. Last but not the least, our proposed algorithms have a much lower time complexity than the existing approach.published_or_final_versio

BGP ingress-to-egress route configuration in a capacity-constrained AS

The BGP ingress-to-egress route configuration problem is to find a set of paths in an ISP to carry the transit flows, such that the amount of network resources consumed is minimized without violating the bandwidth constraint on all network links. To solve the problem, we first formulate it using Integer Linear Programming (ILP). Due to the high complexity involved in ILP, a heuristic algorithm, called MPPF, is then proposed. MPPF is designed based on the idea that heavily-loaded destination prefixes should be given higher priority to select less expensive edge links and routes. Simulation results show that MPPF requires less network resources and edge link capacity than an alternative heuristic called BTF. © 2005 IEEE.published_or_final_versio

BGP ingress-to-egress route configuration in a capacity-constrained AS

The BGP ingress-to-egress route configuration problem is to find a set of paths in an ISP to carry the transit flows, such that the amount of network resources consumed is minimized without violating the bandwidth constraint on all network links. To solve the problem, we first formulate it using Integer Linear Programming (ILP). Due to the high complexity involved in ILP, a heuristic algorithm, called MPPF, is then proposed. MPPF is designed based on the idea that heavily-loaded destination prefixes should be given higher priority to select less expensive edge links and routes. Simulation results show that MPPF requires less network resources and edge link capacity than an alternative heuristic called BTF. © 2005 IEEE.published_or_final_versio

SPECS: Secure and privacy enhancing communications schemes for VANETs

This journal issue entitled: Advances in Ad Hoc Networks (I)Vehicular ad hoc network (VANET) is an emerging type of networks which facilitates vehicles on roads to communicate for driving safety. The basic idea is to allow arbitrary vehicles to broadcast ad hoc messages (e.g. traffic accidents) to other vehicles. However, this raises the concern of security and privacy. Messages should be signed and verified before they are trusted while the real identity of vehicles should not be revealed, but traceable by authorized party. Existing solutions either rely heavily on a tamper-proof hardware device, or cannot satisfy the privacy requirement and do not have an effective message verification scheme. In this paper, we provide a software-based solution which makes use of only two shared secrets to satisfy the privacy requirement (with security analysis) and gives lower message overhead and at least 45% higher successful rate than previous solutions in the message verification phase using the bloom filter and the binary search techniques (through simulation study). We also provide the first group communication protocol to allow vehicles to authenticate and securely communicate with others in a group of known vehicles. © 2010 Elsevier B.V. All rights reserved.postprin

VSPN: VANET-based Secure and Privacy-preserving Navigation

postprin

Routing algorithm for provisioning symmetric virtual private networks in the hose model

A virtual private network (VPN) is a private data network where remote sites are connected over a shared provider network. In order to provide secure communications between customer sites, predetermined paths are used to forward data packets. To support quality of service (QoS), bandwidth has to be reserved on these paths. Then, finding appropriate paths in order to optimize the bandwidth used becomes an important problem. In this paper, we study the routing problem of VPNs under the hose model, where VPN endpoints specify the maximum bandwidth they need in sending and receiving data. Some previous works considered the problem under the assumption that all links have infinite capacities. We remove this constraint in our studies and develop enhancement to existing algorithms. Our simulation results show that our algorithm works very well in networks where link capacities are tight. © 2005 IEEE.published_or_final_versio

PASS: Privacy-preserving authentication scheme for smart grid network

A smart grid power system is capable of adjusting the amount of electricity generated based on real-time requests from the smart meters of customers, thus avoiding excess electricity generation and facilitating reliable and effective transmission of electricity. To ensure that requests are sent from a valid user, all request messages must be authenticated. On the other hand, by analyzing the electricity usage pattern of a customer, the daily habit of the customer, such as when he is away, may be revealed. Thus, a proper privacy preserving mechanism has to be adopted. This paper attempts to develop a scheme to address these two seemingly contradicting requirements efficiently. By using a tamper-resistant device at the smart appliance and pseudo identities, we derive a privacy preserving authentication scheme to solve the problem. The authentication process is made very efficient by means of Hash-based Message Authentication Code (HMAC). Through simulation, we show that with our scheme, the transmission and signature verification delay induced are very small and the message overhead is only 20 bytes per request message. With our efficient verification process, even under attack, the substation can effectively drop all attack messages, allowing 6 times more valid messages to reach the control center when compared to the case without any verification. Thus our scheme is both efficient and effective. © 2011 IEEE.published_or_final_versionThe 2nd IEEE International Conference on Smart Grid Communications (SmartGridComm 2011), Brussels, Belgium, 17-20 October 2011. In Proceedings of the 2nd Smartgridcomm, 2011, p. 196-20