Multiprotocol over WDM in the Access and Metropolitan Networks

IP over WDM ◽  
2004 ◽  
pp. 181-227 ◽  
Author(s):  
Maurice Gagnaire
Keyword(s):  
Metropolitan Networks

Quantum cryptography: Theoretical protocols for quantum key distribution and tests of selected commercial QKD systems in commercial fiber networks

2016 ◽  
Vol 14 (02) ◽  
pp. 1630002
Author(s):  
Monika Jacak ◽  
Janusz Jacak ◽  
Piotr Jóźwiak ◽  
Ireneusz Jóźwiak
Keyword(s):  
Quantum Cryptography ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Current Status ◽  
Entangled Photons ◽  
Fiber Networks ◽  
System Improvement ◽  
Metropolitan Networks

The overview of the current status of quantum cryptography is given in regard to quantum key distribution (QKD) protocols, implemented both on nonentangled and entangled flying qubits. Two commercial R&D platforms of QKD systems are described (the Clavis II platform by idQuantique implemented on nonentangled photons and the EPR S405 Quelle platform by AIT based on entangled photons) and tested for feasibility of their usage in commercial TELECOM fiber metropolitan networks. The comparison of systems efficiency, stability and resistivity against noise and hacker attacks is given with some suggestion toward system improvement, along with assessment of two models of QKD.

scholarly journals Lost in transportation: Information measures and cognitive limits in multilayer navigation

2016 ◽  
Vol 2 (2) ◽  
pp. e1500445 ◽  
Author(s):  
Riccardo Gallotti ◽  
Mason A. Porter ◽  
Marc Barthelemy
Keyword(s):  
New York ◽  
Transportation Networks ◽  
Transportation Systems ◽  
Traditional View ◽  
Multimodal Transportation ◽  
Large Cities ◽  
Amount Of Information ◽  
Information Measures ◽  
Transportation Modes ◽  
Metropolitan Networks

Cities and their transportation systems become increasingly complex and multimodal as they grow, and it is natural to wonder whether it is possible to quantitatively characterize our difficulty navigating in them and whether such navigation exceeds our cognitive limits. A transition between different search strategies for navigating in metropolitan maps has been observed for large, complex metropolitan networks. This evidence suggests the existence of a limit associated with cognitive overload and caused by a large amount of information that needs to be processed. In this light, we analyzed the world’s 15 largest metropolitan networks and estimated the information limit for determining a trip in a transportation system to be on the order of 8 bits. Similar to the “Dunbar number,” which represents a limit to the size of an individual’s friendship circle, our cognitive limit suggests that maps should not consist of more than 250 connection points to be easily readable. We also show that including connections with other transportation modes dramatically increases the information needed to navigate in multilayer transportation networks. In large cities such as New York, Paris, and Tokyo, more than 80% of the trips are above the 8-bit limit. Multimodal transportation systems in large cities have thus already exceeded human cognitive limits and, consequently, the traditional view of navigation in cities has to be revised substantially.

DQDB/sup +/-/: a fair and waste-free media access protocol for dual bus metropolitan networks

1993 ◽  
Vol 41 (12) ◽  
pp. 1805-1815 ◽  
Author(s):  
I.F. Akyildiz ◽  
J. Liebeherr ◽  
A.N. Tantawi
Keyword(s):  
Media Access ◽  
Access Protocol ◽  
Metropolitan Networks ◽  
Free Media
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