Network Timing and the 2015 Leap Second
نویسندگان
چکیده
Using a testbed with reference timestamping, we collected timing data from public Stratum-1 NTP servers during the leap second event of end-June 2015. We found a wide variety of anomalous serverside behaviors, both at the NTP protocol level and in the server clocks themselves, which can last days or even weeks after the event. Out of 176 servers, only 61% had no erroneous behavior related to the leap second event that we could detect.
منابع مشابه
A study on some properties of leap graphs
In a graph G, the first and second degrees of a vertex v is equal to thenumber of their first and second neighbors and are denoted by d(v/G) andd 2 (v/G), respectively. The first, second and third leap Zagreb indices are thesum of squares of second degrees of vertices of G, the sum of products of second degrees of pairs of adjacent vertices in G and the sum of products of firs...
متن کاملOn leap Zagreb indices of graphs
The first and second Zagreb indices of a graph are equal, respectively, to the sum of squares of the vertex degrees, and the sum of the products of the degrees of pairs of adjacent vertices. We now consider analogous graph invariants, based on the second degrees of vertices (number of their second neighbors), called leap Zagreb indices. A number of their basic properties is established.
متن کاملLeap Zagreb indices of trees and unicyclic graphs
By d(v|G) and d_2(v|G) are denoted the number of first and second neighborsof the vertex v of the graph G. The first, second, and third leap Zagreb indicesof G are defined asLM_1(G) = sum_{v in V(G)} d_2(v|G)^2, LM_2(G) = sum_{uv in E(G)} d_2(u|G) d_2(v|G),and LM_3(G) = sum_{v in V(G)} d(v|G) d_2(v|G), respectively. In this paper, we generalizethe results of Naji et al. [Commun. Combin. Optim. ...
متن کاملImproving Tor security against timing and traffic analysis attacks with fair randomization
The Tor network is probably one of the most popular online anonymity systems in the world. It has been built based on the volunteer relays from all around the world. It has a strong scientific basis which is structured very well to work in low latency mode that makes it suitable for tasks such as web browsing. Despite the advantages, the low latency also makes Tor insecure against timing and tr...
متن کاملطراحی و ارزیابی روش کدگذاری ترکیبی برای کانال پوششی زمانبندیدار در شبکه اینترنت
Covert channel means communicating information through covering of overt and authorized channel in a manner that existence of channel to be hidden. In network covert timing channels that use timing features of transmission packets to modulating covert information, the appropriate encoding schema is very important. In this paper, a hybrid encoding schema proposed through combining "the inter-pac...
متن کامل