Biblio

In this article, authors present the results of testing the modified HTB traffic control algorithm in an experimental setup. The algorithm is implemented as a Linux kernel module. An analysis of the experimental results revealed the effect of uneven packet loss in priority classes. In the second part of the article, the authors propose a solution to this problem by applying a distribution scheme for the excess of tokens, according to which excess class tokens are given to the leaf with the highest priority. The new modification of the algorithm was simulated in the AnyLogic environment. The results of an experimental study demonstrated that dividing the excess tokens of the parent class between daughter classes is less effective in terms of network performance than allocating the excess tokens to a high-priority class during the competition for tokens between classes. In general, a modification of the HTB algorithm that implements the proposed token surplus distribution scheme yields more consistent delay times for the high-priority class.

The distribution of video contents generated by Content Providers (CPs) significantly contributes to increase the congestion within the networks of Internet Service Providers (ISPs). To alleviate this problem, CPs can serve a portion of their catalogues to the end users directly from servers (i.e., the caches) located inside the ISP network. Users served from caches perceive an increased QoS (e.g., average retrieval latency is reduced) and, for this reason, caching can be considered a form of traffic prioritization. Hence, since the storage of caches is limited, its subdivision among several CPs may lead to discrimination. A static subdivision that assignes to each CP the same portion of storage is a neutral but ineffective appraoch, because it does not consider the different popularities of the CPs' contents. A more effective strategy consists in dividing the cache among the CPs proportionally to the popularity of their contents. However, CPs consider this information sensitive and are reluctant to disclose it. In this work, we propose a protocol based on Shamir Secret Sharing (SSS) scheme that allows the ISP to calculate the portion of cache storage that a CP is entitled to receive while guaranteeing network neutrality and resource efficiency, but without violating its privacy. The protocol is executed by the ISP, the CPs and a Regulator Authority (RA) that guarantees the actual enforcement of a fair subdivision of the cache storage and the preservation of privacy. We perform extensive simulations and prove that our approach leads to higher hit-rates (i.e., percentage of requests served by the cache) with respect to the static one. The advantages are particularly significant when the cache storage is limited.