• When & Where: Seminars are generally (please, check the timeline and location before coming!) held on:
    • Wednesday afternoon at LINCS (14h-15h, Salle de Conseil) and
    • Thursday afternoon at Barrault (14h-15h, Amphi Saphir).
  • Contact us: if you wish to give a talk, please contact

[Next talks] [All talks]

03/12/2014Raluca Maria Indre (Orange)Evaluating user-perceived performance in FTTH access networks
10/12/2014Marco Mellia (Politecnico di Torino)Is there a case for mobile phone content pre-staging

Date:03/12/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Raluca Maria Indre (Orange)
Talk:Evaluating user-perceived performance in FTTH access networks
Abstract:We evaluate the performance perceivedby end-users connected to a backhaul link thataggregates the traffic of multiple access areas. We model, at flowlevel, the way a finite population of users with heterogeneousaccess rates and traffic demands shares the capacity of thiscommon backhaul link. We then evaluate several practicallyinteresting use cases, focusing particularly on the performance ofusers subscribing to recent FTTH offers in which the user accessrates are in the same order of magnitude as the backhaul linkcapacity. We show that, despite such high access rates, reasonableperformance can be achieved as long as the total offered traffic iswell below the backhaul link capacity. The obtained performanceresults are used to derive simple dimensioning guidelines.
Links:back to the list item, list top or summary top

Date:10/12/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Marco Mellia (Politecnico di Torino)
Talk:Is there a case for mobile phone content pre-staging
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. Assuch, 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' 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..
Links:back to the list item, list top or summary top