As a prominent feature of Named Data Networking (NDN), in-network caching plays an important role in improving the performance of content delivery. However, if each NDN router indiscriminately caches every data packet passing by (i.e., Caching Everything Everywhere (CEE)), the result can be unnecessarily frequent cache replacement and cache redundancy in en-route routers and thus in-network caches are not utilized in an efficient way [1], [2]. Moreover, managing these in-network caches in a centralized way may lead to excessive resource consumption since the number of these caches is considerable. This work proposes a distributed and opportunistic on-path caching scheme. To be specific, each en-route router independently picks content items to cache in such a way that popular content is more likely to be cached by routers, especially routers near users, and cache redundancy is reduced. Extensive simulations including trace-driven ones in a PoP-level ISP topology suggest that the proposed scheme improves the average cache hit ratio of users' requests and reduces the average hop count as compared to CEE and the other on-path caching algorithms considered herein.

Round-trip time (RTT) is an important performance metric. Traditional RTT estimation methods usually depend on the cooperation of other networks and particular active or passive measurement platforms, whose global deployments are costly and difficult. Thus a new RTT estimation algorithm, ME algorithm, is introduced. It can estimate the RTT of two hosts communicating through border routers by using TCP CUBIC bulk flow data from those routhers without the use of extra facilities, which makes the RTT estimation in large-scale high-speed networks more effective. In addition, a simpler and more accurate algorithm — AE algorithm — is presented and used when the link has large bandwidth and low packet loss rate. The two proposed algorithms suit sampled flow data because only duration and total packet number of a TCP CUBIC bulk flow are inputs to their calculations. Experimental results show that both algorithms work excellently in real situations. Moreover, they have the potential to be adapted to other TCP versions with slight modification as their basic idea is independent of the TCP congestion control mechanism.

The objective of this paper is to extend the dosimetric assessment of 35mm Petri dishes exposed in the standing wave of R18 waveguides operated at 1950MHz for a medium-oil two-layer configuration for cells in monolayer and suspension. The culture medium inside the Petri dish is covered by oil that prevents evaporation and seals the cells below in the medium. The exposure of the cells was analyzed for one suspension-medium configuration, two different suspension-multilayer configurations, and one monolayer-multilayer configuration. The numerical dosimetry is verified by dosimetric temperature measurements. The non-uniformity of the specific absorption rate (SAR) distribution is 30% for monolayer, and 59-75% for suspension configurations. The latter should be taken into account when biological experiment is performed.