@article {Ber2014, title = {A Distributed Architecture for the Monitoring of Clouds and CDNs: Applications to Amazon AWS}, journal = {IEEE Transactions on Network and Service Management}, volume = {In press}, year = {2014}, abstract = {

Clouds and CDNs are systems that tend to separate the content being requested by users from the physical servers capable of serving it. From the network point of view, monitoring and optimizing performance for the traffic they generate is a challenging task, given the same resource can be located in multiple places, which can in turn change at any time. The first step in understanding Cloud and CDN systems is thus the engineering of a monitoring platform. In this paper, we propose a novel solution which combines passive and active measurements, and whose workflow has been tailored to specifically characterize the traffic generated by Cloud and CDN infrastructures. We validate our platform by performing a longitudinal characterization of the very well known Cloud and CDN infrastructure provider Amazon Web Services (AWS). By observing the traffic generated by more than 50,000 Internet users of an Italian ISP, we explore the EC2, S3 and CloudFront AWS services, unveiling their infrastructure, the pervasiveness of web-services they host, and their traffic allocation policies as seen from our vantage points. Most importantly, we observe their evolution over a two- year long period. The solution provided in this paper can be of interest for i) developers aiming at building measurement tools for Cloud Infrastructure Providers, ii) developers interested in failure and anomaly detection systems, and iii) third-party SLA certificators who can design systems to independently monitor performance. At last, we believe the results about AWS presented in this paper are interesting as they are among the first to unveil properties of AWS as seen from the operator point of view.

}, keywords = {Amazon, AWS, CDNs, Clouds}, author = {Ignacio Bermudez and Stefano Traverso and Marco Mellia and Maurizio 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} }