scholarly journals Topology Poisoning Attacks and Prevention in Hybrid Software-Defined Networks

2021 ◽  
Author(s):  
Pragati Shrivastava ◽  
Kotaro Kataoka
Keyword(s):  
High Accuracy ◽  
Virtual Network ◽  
Smooth Transition ◽  
Software Defined Networks ◽  
Inconsistency Management ◽  
Link Discovery ◽  
New Challenges ◽  
First Time ◽  
Sdn Controller ◽  
Hybrid Sdn

<p>The hybrid software-defined networks (SDN) architectures are beneficial for a smooth transition and less costly SDN deployment. However, legacy switches and SDN switches coexistence brings new challenges of deployment inconsistency management and security. Security is not well studied for hybrid SDN architecture. In this paper, we study the topology poisoning attacks in hybrid SDN for the first time. We propose new attack vectors for link fabrication in hybrid SDN. The new attack is named “multi-hop link fabrication”, in which an adversary successfully injects a fake multi-hop link (MHL) by exploiting the link discovery protocols. We presented the Hybrid-Shield, a link verification framework for hybrid SDN link discovery. Hybrid-Shield introduces a novel verification technique that includes: i) monitoring legacy switch and host generated traffic at MHL and ii) validating the existence of legacy switches contained in an MHL. This paper presents the prototype implementation of Hybrid-Shield over a real SDN controller. The experimental evaluation is performed with the mininet virtual network emulation. Our evaluation shows that Hybrid-Shield is capable of detecting MHL fabrication attacks in real-time with high accuracy. Hybrid-Shield’s performance evaluation shows that it is lightweight at the controller as it causes less overhead and requires no additional functionalities at the SDN controller for deployment.</p>

scholarly journals Topology Poisoning Attacks and Prevention in Hybrid Software-Defined Networks

2021 ◽  
Author(s):  
Pragati Shrivastava ◽  
Kotaro Kataoka
Keyword(s):  
High Accuracy ◽  
Virtual Network ◽  
Smooth Transition ◽  
Software Defined Networks ◽  
Inconsistency Management ◽  
Link Discovery ◽  
New Challenges ◽  
First Time ◽  
Sdn Controller ◽  
Hybrid Sdn

<p>The hybrid software-defined networks (SDN) architectures are beneficial for a smooth transition and less costly SDN deployment. However, legacy switches and SDN switches coexistence brings new challenges of deployment inconsistency management and security. Security is not well studied for hybrid SDN architecture. In this paper, we study the topology poisoning attacks in hybrid SDN for the first time. We propose new attack vectors for link fabrication in hybrid SDN. The new attack is named “multi-hop link fabrication”, in which an adversary successfully injects a fake multi-hop link (MHL) by exploiting the link discovery protocols. We presented the Hybrid-Shield, a link verification framework for hybrid SDN link discovery. Hybrid-Shield introduces a novel verification technique that includes: i) monitoring legacy switch and host generated traffic at MHL and ii) validating the existence of legacy switches contained in an MHL. This paper presents the prototype implementation of Hybrid-Shield over a real SDN controller. The experimental evaluation is performed with the mininet virtual network emulation. Our evaluation shows that Hybrid-Shield is capable of detecting MHL fabrication attacks in real-time with high accuracy. Hybrid-Shield’s performance evaluation shows that it is lightweight at the controller as it causes less overhead and requires no additional functionalities at the SDN controller for deployment.</p>

scholarly journals Link Discovery Attacks in Software-Defined Networks: Topology Poisoning and Impact Analysis

2020 ◽  
pp. 596-606
Author(s):  
Sonali Sen Baidya ◽  
◽  
Rattikorn Hewett
Keyword(s):  
Network Management ◽  
Empirical Analysis ◽  
Impact Analysis ◽  
Defense Mechanism ◽  
Software Defined Networks ◽  
Discovery Process ◽  
Defense Systems ◽  
And Topology ◽  
Link Discovery ◽  
Sdn Controller

Software Defined Networking (SDN) has become a popular technology that offers advantages of programmable and flexible network management over the legacy practice. The centralized SDN controller is an important enabler of these benefits. One of the most crucial tasks of the SDN controller is link discovery as it provides topology of the network essential for the controller to direct or create rule forwarding and routing mechanisms. Much research on SDN security has been studied but only recently that security of OpenFlow link discovery protocols and topology poisoning have been addressed. Existing work includes link fabrication attacks via compromised hosts and defense systems with authentication. This paper discusses SDN link discovery process and its vulnerability to link discovery attacks including new attacks via compromised switches. We present a simple but effective defense mechanism using active ports that can detect both host-based and switch-based link discovery attacks. Finally, the paper presents an analytical and empirical analysis of the impacts of topology attacks on routing. The paper discusses attack details, proposed methods and results of these analyses.

Implementing the London Dumping Convention in East Asia

2017 ◽  
Vol 2 (2) ◽  
pp. 247-267 ◽  
Author(s):  
Keyuan Zou ◽  
Lei Zhang
Keyword(s):  
South Korea ◽  
East Asia ◽  
Carbon Storage ◽  
Marine Pollution ◽  
East Asian ◽  
The Philippines ◽  
New Challenges ◽  
The Republic ◽  
London Protocol ◽  
First Time

In 1972, the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention) was negotiated. It is a global treaty, for the first time, to regulate dumping of waste at sea worldwide. Following this global endeavor, the Protocol to the London Convention (London Protocol) was later agreed to further modernize the London Convention so as to reinforce the management of dumping of waste at sea. While in East Asia, only China, Japan, the Republic of Korea (South Korea) and the Philippines have acceded to the Convention and its Protocol, other countries do not show their willingness to sign them. Against this background, this article will address the responses of these East Asian states to the implementation of the London Convention, and analyze and assess their relevant laws and regulations with particular reference to China’s practice. In addition, it will focus on new challenges, such as offshore carbon storage, to the London Convention.

scholarly journals Astrometric Programs by the New Hamburg Plate Measuring Machine

1994 ◽  
Vol 161 ◽  
pp. 173-176
Author(s):  
Chr. de Vegt ◽  
L. Winter ◽  
N. Zacharias
Keyword(s):  
Reference Frame ◽  
Northern Hemisphere ◽  
High Accuracy ◽  
Proper Motions ◽  
Sky Surveys ◽  
Unique Data ◽  
Large Sets ◽  
Measuring Machine ◽  
First Time

With the new Hamburg astrometric measuring machine, large sets of plates can be digitized very quickly with submicrometer accuracy. In particular about 2000 plates of the AGK2-catalog, mean epoch 1930, can be remeasured now for the first time to their limiting magnitude, about B = 11. The new AGK2-data therefore will cover practically the whole AC-catalog and TYCHO-stars in the northern hemisphere. All plates will be reduced using the HIPPARCOS results as the reference frame when available in 1996. The new AGK2-data will provide a unique data base for the determination of high accuracy proper motions (about 2 mas/yr) of all TYCHO stars in the northern hemisphere. Furthermore, for the first time a dense reference frame for a final reduction of the Astrographic Catalog (AC) and the large deep sky surveys will be generated by this catalog. The inferior situation in the southern hemisphere will be addressed briefly.

The Conscription of Greek Ottomans into the Sultan's Army, 1908–1912

2020 ◽  
Vol 52 (3) ◽  
pp. 433-448
Author(s):  
Uğur Z. Peçe
Keyword(s):  
Ottoman Empire ◽  
Military Service ◽  
Diverse Population ◽  
Greek Language ◽  
Muslim Population ◽  
Military Conscription ◽  
Ottoman History ◽  
New Challenges ◽  
The Military ◽  
First Time

AbstractWith the reinstatement of the parliament in 1908, the Ottoman state faced new challenges connected to citizenship. As a policy to finally make citizens equal in rights as well as duties, military conscription figured prominently in this new context. For the first time in Ottoman history, the empire's non-Muslims began to be drafted en masse. This article explores meanings of imperial citizenship and equality through the lens of debates over the conscription of Greek Ottomans, the largest non-Muslim population of the Ottoman Empire. In contrast to the widespread suggestion of the Turkish nationalist historiography on these matters, Greek Ottomans and other non-Muslim populations enthusiastically supported the military service in principle. But amidst this general agreement was a tremendous array of views on what conscription ought to look like in practice. The issue came to center on whether Greek Ottomans should have separate battalions in the army. All units would eventually come to be religiously integrated, but the conscription debates in the Ottoman parliament as well as in the Turkish and Greek language press reveal some of the crucial fissures of an empire as various actors were attempting to navigate between a unified citizenship and a diverse population.

High-accuracy X-ray absorption spectra from mMsolutions of nickel (II) complexes with multiple solutions using transmission XAS

2015 ◽  
Vol 22 (4) ◽  
pp. 1008-1021 ◽  
Author(s):  
Christopher T. Chantler ◽  
M. Tauhidul Islam ◽  
Stephen P. Best ◽  
Lachlan J. Tantau ◽  
Chanh Q. Tran ◽  
...  
Keyword(s):  
Multiple Solutions ◽  
High Accuracy ◽  
Hybrid Technique ◽  
Edge Structure ◽  
New Approach ◽  
X Ray ◽  
Square Planar ◽  
Transmission Measurements ◽  
First Time ◽  
X Ray Absorption

A new approach is introduced for determining X-ray absorption spectroscopy (XAS) spectra on absolute and relative scales using multiple solutions with different concentrations by the characterization and correction of experimental systematics. This hybrid technique is a development of standard X-ray absorption fine structure (XAFS) along the lines of the high-accuracy X-ray extended range technique (XERT) but with applicability to solutions, dilute systems and cold cell environments. This methodology has been applied to determining absolute XAS of bis(N-n-propyl-salicylaldiminato) nickel(II) and bis(N-i-propyl-salicylaldiminato) nickel(II) complexes with square planar and tetrahedral structures in 15 mMand 1.5 mMdilute solutions. It is demonstrated that transmission XAS from dilute systems can provide excellent X-ray absorption near-edge structure (XANES) and XAFS spectra, and that transmission measurements can provide accurate measurement of subtle differences including coordination geometries. For the first time, (transmission) XAS of the isomers have been determined from low-concentration solutions on an absolute scale with a 1–5% accuracy, and with relative precision of 0.1% to 0.2% in the active XANES and XAFS regions after inclusion of systematic corrections.

scholarly journals Detection of magnetic fields in He-rich early B-type stars using HARPSpol

2018 ◽  
Vol 618 ◽  
pp. L2 ◽  
Author(s):  
S. P. Järvinen ◽  
S. Hubrig ◽  
I. Ilyin ◽  
M. Schöller ◽  
M. F. Nieva ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Longitudinal Magnetic Field ◽  
High Accuracy ◽  
Photometric Data ◽  
The Other ◽  
High Spectral Resolution ◽  
Periodic Modulation ◽  
First Time ◽  
The Magnetic Field

Aims. We focus on early-B type stars with helium overabundance, for which the presence of a magnetic field has not previously been reported. Methods. The measurements were carried out using high-spectral-resolution spectropolarimetric observations obtained with the High Accuracy Radial velocity Planet Searcher (HARPS) in polarimetric mode, installed at the ESO La Silla 3.6 m telescope. Results. For five He-rich stars, the longitudinal magnetic field was detected for the first time. For one target, HD 58260, the presence of a longitudinal magnetic field of the order of 1.8 kG has already been reported in the literature, but the magnetic field has remained constant over tens of years. Our measurement carried out using the polarimetric spectra obtained in 2015 March indicates a slight decrease of the longitudinal magnetic field strength compared to measurements reported in previous works. A search for periodic modulation in available photometric data allowed us to confidently establish a period of 2.64119 ± 0.00420 d in archival ASAS3 data for CPD–27°1791. No period could be determined for the other five stars. Conclusions. The obtained results support the scenario that all He-rich stars are detectably magnetic and form an extension of the Ap star phenomenon to higher temperatures.

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