@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} } @inbook {Sil2014, title = {Aggregation of Statistical Data from Passive Probes: Techniques and Best Practices}, booktitle = {Traffic Monitoring and Analysis}, series = {Lecture Notes in Computer Science}, volume = {8406}, year = {2014}, pages = {38-50}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, abstract = {

Passive probes continuously generate statistics on large number of metrics, that are possibly represented as probability mass functions (pmf). The need for consolidation of several pmfs arises in two contexts, namely: (i) whenever a central point collects and aggregates measurement of multiple disjoint vantage points, and (ii) whenever a local measurement processed at a single vantage point needs to be distributed over multiple cores of the same physical probe, in order to cope with growing link capacity. In this work, we take an experimental approach and study both cases using, whenever possible, open source software and datasets. Considering different consolidation strategies, we assess their accuracy in estimating pmf deciles (from the 10th to the 90th) of diverse metrics, obtaining general design and tuning guidelines. In our dataset, we find that Monotonic Spline Interpolation over a larger set of percentiles (e.g., adding 5th, 10th, 15th, and so on) allow fairly accurate pmf consolidation in both the multiple vantage points (median error is about 1\%, maximum 30\%) and local processes (median 0.1\%, maximum 1\%) cases.

}, keywords = {Data aggregation, data reduction, scalability problem}, isbn = {978-3-642-54998-4}, doi = {10.1007/978-3-642-54999-1_4}, url = {http://dx.doi.org/10.1007/978-3-642-54999-1_4}, author = {Colabrese, Silvia and Rossi, Dario and Mellia, Marco} } @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} }