@inproceedings {DR:TRAC-15, title = {Impact of Carrier-Grade NAT on Web Browsing}, booktitle = { 6th International Workshop on TRaffic Analysis and Characterization (TRAC) - The paper won the BEST PAPER award}, year = {2015}, month = {08/2015}, publisher = {IEEE}, organization = {IEEE}, address = {Dobrovnik, Croatia}, abstract = {

Public IPv4 addresses are a scarce resource. While IPv6 adoption is lagging, Network Address Translation (NAT) technologies have been deployed over the last years to alleviate IPv4 exiguity and their high rental cost. In particular, Carrier- Grade NAT (CGN) is a well known solution to mask a whole ISP network behind a limited amount of public IP addresses, significantly reducing expenses. Despite its economical benefits, CGN can introduce connectiv- ity issues which have sprouted a considerable effort in research, development and standardization. However, to the best of our knowledge, little effort has been dedicated to investigate the impact that CGN deployment may have on users{\textquoteright} traffic. This paper fills the gap. We leverage passive measurements from an ISP network deploying CGN and, by means of the Jensen- Shannon divergence, we contrast several performance metrics considering customers being offered public or private addresses. In particular, we gauge the impact of CGN presence on users{\textquoteright} web browsing experience. Our results testify that CGN is a mature and stable technology as, if properly deployed, it does not harm users{\textquoteright} web browsing experience. Indeed, while our analysis lets emerge expected stochastic differences of certain indexes (e.g., the difference in the path hop count), the measurements related to the quality of users{\textquoteright} browsing are otherwise unperturbed. Interestingly, we also observe that CGN protects customers from unsolicited, often malicious, traffic.

}, url = {http://www.enst.fr/~drossi/paper/rossi15trac.pdf}, author = {Bocchi, Enrico and Safari, Ali and Traverso, Stefano and Finamore, Alessandro and Di Gennaro, Valeria and Mellia, Marco and Munafo, Maurizio and Rossi, Dario} } @article {6975242, title = {When YouTube Does not Work - Analysis of QoE-Relevant Degradation in Google CDN Traffic}, journal = {Network and Service Management, IEEE Transactions on}, volume = {11}, year = {2014}, month = {Dec}, pages = {441-457}, keywords = {CDN distributed services, CDN server selection strategies, client-server systems, content delivery network, Content Delivery Networks, Degradation, dynamic approach, dynamic server selection strategies, end-user QoE, end-user quality of experience, European ISP, Google, Google CDN traffic, Google server selection strategies, IP networks, iterative structured process, load reduction, QoE-relevant anomaly characterization, QoE-relevant anomaly detection, QoE-relevant anomaly diagnosis, QoE-relevant degradation, Quality of Experience, Servers, social networking (online), statistical analysis, statistical analysis methodologies, Statistical Data Analysis, telecommunication traffic, Traffic Monitoring, Videos, watching experience improvement, YouTube, YouTube flow trace collection, YouTube QoE-relevant degradation, YouTube videos}, issn = {1932-4537}, doi = {10.1109/TNSM.2014.2377691}, author = {Casas, Pedro and D{\textquoteright}Alconzo, Alessandro and Fiadino, Pierdomenico and B{\"a}r, Arian and Finamore, Alessandro and Zseby, Tanja} } @inproceedings {Ale2013, title = {Is There a Case for Mobile Phone Content Pre-staging?}, booktitle = {Proceedings of the Ninth ACM Conference on Emerging Networking Experiments and Technologies (Best Short Paper Award)}, year = {2013}, month = {12/2013}, publisher = {ACM}, organization = {ACM}, address = {New York, NY, USA}, abstract = {

Content caching is a fundamental building block of the Internet. Caches are widely deployed at network edges to improve performance for end-users, and to reduce load on web servers and the backbone network. Considering mobile 3G/4G networks, however, the bottleneck is at the access link, where bandwidth is shared among all mobile terminals. As such, per-user capacity cannot grow to cope with the traffic demand. Unfortunately, caching policies would not reduce the load on the wireless link which would have to carry multiple copies of the same object that is being downloaded by multiple mobile terminals sharing the same access link.

In this paper we investigate if it is worth to push the caching paradigm even farther. We hypothesize a system in which mobile terminals implement a local cache, where popular content can be pushed/pre-staged. This exploits the peculiar broadcast capability of the wireless channels to replicate content "for free" on all terminals, saving the cost of transmitting multiple copies of those popular objects. Relying on a large data set collected from a European mobile carrier, we analyse the content popularity characteristics of mobile traffic, and quantify the benefit that the push-to-mobile system would produce. We found that content pre-staging, by proactively and periodically broadcasting "bundles" of popular objects to devices, allows to both greatly i) improve users{\textquoteright} performance and ii) reduce up to 20\% (40\%) the downloaded volume (number of requests) in optimistic scenarios with a bundle of 100 MB. However, some technical constraints and content characteristics could question the actual gain such system would reach in practice.

}, keywords = {content pre-staging, mobile networks}, isbn = {978-1-4503-2101-3}, doi = {10.1145/2535372.2535414}, url = {http://doi.acm.org/10.1145/2535372.2535414}, author = {Finamore, Alessandro and Mellia, Marco and Gilani, Zafar and Papagiannaki, Konstantina and Erramilli, Vijay and Grunenberger, Yan} }