Browsing by Subject "Internet protocols"

Now showing 1 - 8 of 8

Open Access
Comparison of PI controllers designed for the delay model of TCP/AQM networks
(Elsevier, 2013) Ünal H. U.; Melchor-Aguilar, D.; Üstebay, D.; Niculescu, S. -I.; Özbay, Hitay
One of the major problems of communication networks is congestion. In order to address this problem in TCP/IP networks, Active Queue Management (AQM) scheme is recommended. AQM aims to minimize the congestion by regulating the average queue size at the routers. To improve upon AQM, recently, several feedback control approaches were proposed. Among these approaches, PI controllers are gaining attention because of their simplicity and ease of implementation. In this paper, by utilizing the fluid-flow model of TCP networks, we study the PI controllers designed for TCP/AQM. We compare these controllers by first analyzing their robustness and fragility. Then, we implement these controllers in ns-2 platform and conduct simulation experiments to compare their performances in terms of queue length. Taken together, our results provide a guideline for choosing a PI controller for AQM given specific performance requirements.
Open Access
Energy efficient IP-connectivity with IEEE 802.11 for home M2M networks
(Oxford University Press, 2017) Ozcelik, I. M.; Korpeoglu, I.; Agrawala, A.
Machine-to-machine communication (M2M) technology enables large-scale device communication and networking, including home devices and appliances. A critical issue for home M2M networks is how to efficiently integrate existing home consumer devices and appliances into an IP-based wireless M2M network with least modifications. Due to its popularity and widespread use in closed spaces, Wi-Fi is a good alternative as a wireless technology to enable M2M networking for home devices. This paper addresses the energy-efficient integration of home appliances into a Wi-Fi- and IP-based home M2M network. Toward this goal, we first propose an integration architecture that requires least modifications to existing components. Then, we propose a novel long-term sleep scheduling algorithm to be applied with the existing 802.11 power save mode. The proposed scheme utilizes the multicast DNS protocol to maintain device and service availability when devices go into deep sleep mode. We prototyped our proposed architecture and algorithm to build a M2M network testbed of home appliances. We performed various experiments on this testbed to evaluate the operation and energy savings of our proposal. We also did simulation experiments for larger scale scenarios. As a result of our test-bed and simulation experiments, we observed significant energy savings compared to alternatives while also ensuring device and service availability. © The British Computer Society 2017. All rights reserved.
Open Access
Exact algorithms for the joint object placement and request routing problem in content distribution networks
(2008) Bektaş, T.; Cordeau J.-F.; Erkut, E.; Laporte G.
This paper describes two exact algorithms for the joint problem of object placement and request routing in a content distribution network (CDN). A CDN is a technology used to efficiently distribute electronic content throughout an existing Internet Protocol network. The problem consists of replicating content on the proxy servers and routing the requests for the content to a suitable proxy server in a CDN such that the total cost of distribution is minimized. An upper bound on end-to-end object transfer time is also taken into account. The problem is formulated as a nonlinear integer programming formulation which is linearized in three different ways. Two algorithms, one based on Benders decomposition and the other based on Lagrangean relaxation and decomposition, are described for the solution of the problem. Computational experiments are conducted by comparing the proposed linearizations and the two algorithms on randomly generated Internet topologies. © 2007 Elsevier Ltd. All rights reserved.
Open Access
A path-quality-aware peer-to-peer file sharing protocol for mobile ad-hoc networks: Wi-Share
(IEEE, 2009-09) Karasabun, Efe; Ertemür, Doğuş; Sarıyıldız, Seyhun; Tekkalmaz, Metin; Körpeoğlu, İbrahim
Peer-to-peer networks are rather well-studied and currently there are numerous systems based on peer-to-peer principles running on the Internet. On the other hand peer-to-peer networks for mobile ad-hoc networks have attracted attention only in the recent years. In this paper, we propose a novel peer-to-peer file sharing system particularly designed for mobile ad-hoc networks. The proposed system, namely Wi-Share, has both network and application layer aspects enabling efficient search and download of the shared files. Wi-Share uses reactive routing for the search operation combined with source discovery and uses the routing tables constructed during the search operation for the download operation. In order to increase the overall efficiency of the file sharing in the network, Wi-Share applies techniques to reduce the required traffic and to increase efficient parallelism of the download operation. These techniques include filtering search results, preferring the higher quality routing paths, using partitioned download scheme and allowing the nodes that have joined to the network recently to contribute to the ongoing downloads. Wi-Share is implemented to work on mobile computers and the results of several experiments are also presented in the paper. © 2009 IEEE.
Open Access
Performance analysis of two-level forward error correction for lostcell recovery in ATM networks
(IEEE, 1995-04) Oğuz, Nihat Cem; Ayanoğlu, E.
The major source of errors in B-ISDN/ATM systems is expected to be buffer overflow during congested conditions, resulting in ATM cell losses which degrade the quality of service. It has been shown by many authors that the performance of the end-to-end system can be made much less sensitive to cell loss by means of forward error correction. This paper discusses the use of a two-level forward error correction scheme for virtual channel and virtual path connections in ATM networks. The scheme exploits simple block coding and code interleaving simultaneously. The simple block, interleaved, and joint coding schemes are studied and analyzed by using a novel and accurate discrete-time analytical method which enables the burstiness of cell losses be captured precisely. Detailed performance calculations, which indicate that it is possible to reduce the cell loss rate by several orders of magnitude over a wide range of network load for various traffic conditions, are discussed, and compared with simulation results. The comparisons show that the method is very accurate for bursty traffic. The advantages of the three coding techniques are quantified for different traffic characteristics and scenarios © Copyright 2009 IEEE - All Rights Reserved.
Open Access
Prototype implementation of dynavote e-voting protocol
(ACI, 2009-06) Çetinkaya, O.; Koc, M. Levent
Voting is regarded as one of the most effective methods for individuals to express their opinions on a given topic. Electronic voting (eVoting) refers to the use of computers or computerised voting equipments to cast ballots in an election. eVoting performed over Internet can be universally accepted in the upcoming years due to the fact that Internet plays key roles in people's lives. The DynaVote eVoting protocol claims that it is practical over a network since it does not use complex algorithms and has no physical assumptions such as untappable channels, whereas fulfilling core voting requirements such as privacy, accuracy, uncoercibility and individual verifiability. Software development requires considerable amount of time and money. Therefore, in order to utilise all resources, the prototype implementation gains more importance as it gives quick feedbacks about the practicality of the system. This paper presents a prototype implementation of DynaVote eVoting protocol over the Internet. Since DynaVote relies on PVID scheme, which is an unlinkable pseudo identity mechanism, the prototype includes implementation of PVID scheme component as well. The main outcome of this study is to prove that DynaVote protocol over Internet is practical and applicable in real life and to illustrate that PVID scheme provides unlinkability. This study also contributes some improvements in DynaVote e-voting protocol. Furthermore, this paper analyses how the prototype fulfils some electronic voting system requirements such as efficiency, transparency and mobility.
Open Access
A reordering-free multipath traffic engineering architecture for DiffServ-MPLS networks
(IEEE, 2003-10) Akar, Nail; Hokelek, İbrahim; Atik, Muammer; Karasan, Ezhan
We propose a novel traffic engineering architecture for IP networks with multiprotocol label switching (MPLS) backbones. In this architecture, two (primary and secondary) label switched paths (LSPs) are established among every pair of IP routers located at the edge of an MPLS cloud. Traffic between a source-destination pair is then split between the primary and secondary LSPs using an ABR-like explicit-rate feedback gathered from the network. Taking into consideration the packet reordering effect of packet-based load balancing schemes, we propose a novel traffic splitting mechanism that operates on a per-flow basis. We show, using a variety of scenarios, that deploying flow-based multipath traffic engineering not only provides significantly and consistently better throughput than that of a single path, but is also void of any packet reordering. © 2003 IEEE.
Open Access
A survey on scheduling in IEEE 802.16 mesh mode
(Institute of Electrical and Electronics Engineers, 2010) Kas, M.; Yargicoglu, B.; Korpeoglu, I.; Karasan, E.
IEEE 802.16 standard (also known as WiMAX) defines the wireless broadband network technology which aims to solve the so called last mile problem via providing high bandwidth Internet even to the rural areas for which the cable deployment is very costly. The standard mainly focuses on the MAC and PHY layer issues, supporting two transmission modes: PMP (Point-to-Multipoint) and mesh modes. Mesh mode is an optional mode developed as an extension to PMP mode and it has the advantage of having an improving performance as more subscribers are added to the system using multi-hop routes. In 802.16 MAC protocol, mesh mode slot allocation and reservation mechanisms are left open which makes this topic a hot research area. Hence, the focus of this survey will mostly be on the mesh mode, and the proposed scheduling algorithms and performance evaluation methods. © 2010 IEEE.