@inproceedings {Ber2013, title = {Exploring the Cloud from Passive Measurements: the Amazon AWS case}, booktitle = {The 32nd Annual IEEE International Conference on Computer Communications (INFOCOM{\textquoteright}2013)}, year = {2013}, address = {Turin, Italy}, abstract = {

Cloud Providers are nowadays the most popular way to quickly deploy new services on the Internet. Understanding mechanisms currently adopted in cloud design is fundamental to identify possible bottlenecks, to optimize performance, and to design more efficient platforms. This paper presents a characterization of Amazon{\textquoteright}s Web Services (AWS), the most prominent cloud provider that offers computing, storage, and content delivery platforms. Leveraging passive measurements collected from several vantage points in Italy for several months, we explore the EC2, S3 and CloudFront AWS services to unveil their infrastructure, the pervasiveness of content they host, and their traffic allocation policies. Measurements reveal that most of the content residing on EC2 and S3 is served by one single Amazon datacenter located in Virginia despite it appears to be the worst performing one for Italian users. This causes traffic to take long and expensive paths in the network. Since no automatic migration and load-balancing policies are offered by AWS among different locations, content is exposed to outages, as we were able to observe in our data. The CloudFront CDN, on the contrary, shows much better performance thanks to the effective cache selection policy that serves 98\% of the traffic from the nearest available cache. CloudFront exhibits also dynamic load-balancing policies, in contrast to the static allocation of instances on EC2 and S3. Information presented in this paper will be useful for developers aiming at entrusting AWS to deploy their contents, and for researchers willing to improve cloud design.

}, doi = {10.1109/INFCOM.2013.6566769}, author = {Ignacio Nicolas Bermudez and Stefano Traverso and Marco Mellia and Maurizio M Munafo{\textquoteright}} } @inproceedings {Ber2012, title = {DNS to the rescue: Discerning Content and Services in a Tangled Web}, booktitle = {Internet Measurement Conference 2012}, volume = {1}, year = {2012}, month = {11/2012}, pages = {413-426}, publisher = {ACM}, organization = {ACM}, edition = {ACM}, address = {Boston, MA}, abstract = {

A careful perusal of the Internet evolution reveals two major trends - explosion of cloud-based services and video stream- ing applications. In both of the above cases, the owner (e.g., CNN, YouTube, or Zynga) of the content and the organiza- tion serving it (e.g., Akamai, Limelight, or Amazon EC2) are decoupled, thus making it harder to understand the associ- ation between the content, owner, and the host where the content resides. This has created a tangled world wide web that is very hard to unwind, impairing ISPs{\textquoteright} and network administrators{\textquoteright} capabilities to control the traffic flowing in their networks.

In this paper, we present DN-Hunter, a system that lever- ages the information provided by DNS traffic to discern the tangle. Parsing through DNS queries, DN-Hunter tags traf- fic flows with the associated domain name. This association has several applications and reveals a large amount of use- ful information: (i) Provides a fine-grained traffic visibility even when the traffic is encrypted (i.e., TLS/SSL flows), thus enabling more effective policy controls, (ii) Identifies flows even before the flows begin, thus providing superior net- work management capabilities to administrators, (iii) Un- derstand and track (over time) different CDNs and cloud providers that host content for a particular resource, (iv) Discern all the services/content hosted by a given CDN or cloud provider in a particular geography and time interval, and (v) Provides insights into all applications/services run- ning on any given layer-4 port number.

We conduct extensive experimental analysis and show re- sults from real traffic traces (including FTTH and 4G ISPs) that support our hypothesis. Simply put, the information provided by DNS traffic is one of the key components re- quired for understanding the tangled web, and bringing the ability to effectively manage network traffic back to the op- erators.\ 

}, keywords = {DNS, mPlane, passive measurement, WP2}, isbn = {978-1-4503-1705-4}, doi = {10.1145/2398776.2398819}, url = {http://dl.acm.org/citation.cfm?id=2398776.2398819\&coll=DL\&dl=GUIDE\&CFID=225051145\&CFTOKEN=42401286}, author = {Ignacio Nicolas Bermudez and Marco Mellia and Maurizio M Munafo{\textquoteright} and Ram Keralapura and Antonio Nucci} } @inproceedings {Dra2012, title = {Inside Dropbox: Understanding Personal Cloud Storage Services}, booktitle = {Internet Measurement Conference - IMC}, year = {2012}, month = {11/2012}, publisher = {ACM}, organization = {ACM}, address = {Boston, MA}, abstract = {

Personal cloud storage services are gaining popularity. With a rush of providers to enter the market and an increasing of- fer of cheap storage space, it is to be expected that cloud storage will soon generate a high amount of Internet traffic. Very little is known about the architecture and the perfor- mance of such systems, and the workload they have to face. This understanding is essential for designing efficient cloud storage systems and predicting their impact on the network.

This paper presents a characterization of Dropbox, the leading solution in personal cloud storage in our datasets. By means of passive measurements, we analyze data from four vantage points in Europe, collected during 42 consecu- tive days. Our contributions are threefold: Firstly, we are the first to study Dropbox, which we show to be the most widely-used cloud storage system, already accounting for a volume equivalent to around one third of the YouTube traffic at campus networks on some days. Secondly, we character- ize the workload users in different environments generate to the system, highlighting how this reflects on network traf- fic. Lastly, our results show possible performance bottle- necks caused by both the current system architecture and the storage protocol. This is exacerbated for users connected far from storage data-centers.

All measurements used in our analyses are publicly avail- able in anonymized form at the SimpleWeb trace repository: http://traces.simpleweb.org/dropbox/

}, keywords = {Dropbox, passive measurement}, issn = {978-1-4503-1705-4}, doi = {10.1145/2398776.2398827}, url = {http://dl.acm.org/citation.cfm?id=2398776.2398827\&coll=DL\&dl=GUIDE\&CFID=225051145\&CFTOKEN=42401286}, author = {Idilio Drago and Marco Mellia and Maurizio M Munafo{\textquoteright} and Anna Sperotto and Ramin Sadre and Aiko Pras} } @inproceedings {Fin2012, title = {The need for an intelligent measurement plane: The example of time-variant CDN policies}, booktitle = {Telecommunications Network Strategy and Planning Symposium (NETWORKS), 2012 XVth International }, year = {2012}, month = {10/2012}, pages = {1 - 6 }, abstract = {In this paper we characterize how web-based services are delivered by large organizations in today{\textquoteright}s Internet. Taking advantage oftwo week-long data sets separated in time by 10 months and reporting the web activity of more than 10,000 ADSL residential customers, we identify the services offered by large organizations like Google, Akamai and Amazon. We then compare theevolution of both policies used to serve requests, and the infrastructure they use to match the users{\textquoteright} demand. Results depict anovercrowded scenario in constant evolution. Big-players are more and more responsible for the majority of the volume and a plethora of other organizations offering similar or more specific services through different CDNs and traffic policies. Unfortunately, no standard tools and methodologies are available to capture and expose the hidden properties of this in constant evolution picture. A deeper understanding of such dynamics is however fundamental to improve the performance of current and future Internet. To this extend, we claim the need for a Internet-wide, standard, flexible and intelligent measurement plane to be added tothe current Internet infrastructure.}, keywords = {Facebook, Google, Monitoring, Organizations, Servers, Streaming media, Throughput}, issn = {978-1-4673-1390-2}, doi = {http://dx.doi.org/10.1109/NETWKS.2012.6381662}, author = {Alessandro Finamore and Vinicius Gehlen and Marco Mellia and Maurizio M Munafo{\textquoteright}} }