Status date

The objective of youCache is to bring an idea to success that was born nearly ten years ago, SiMPLE (“Satellite interactive Multimedia Platform for Low-cost Earth-stations”).

SiMPLE addresses the observation that more than 90 per cent of the web traffic stems from less than 10 per cent of web servers with a satellite based multicast web caching system.  Repetitious content is cached and served to the users without latency and each request served from the client cache consequently saves costly satellite bandwidth.

ASTRA2Connect is an already deployed commercial two-way satellite system operated by the project partner SES ASTRA, serving the end-user market at DSL-like costs Efficient use of the satellite capacity is of utmost commercial importance, because less capacity consumption per user means more users per transponder.

Consequently, the integration of SiMPLE into the ASTRA2Connect system, as the initial target, for exploiting the effectiveness and efficiency of web caching is considered a commercially attractive solution, that may well be adapted to other two-way satellite systems addressing the residential market.


Multicast web caching will be integrated to improve the performance of the targetted ASTRA2Connect system. This will result in a higher number of users within the same transmission capacity. Hence, the costs per users will be lower and the perceived service will be better since already transmitted content cached in the clients cache (frequently consumed content even from other clients) can be forwarded immediately to the client browser, thus avoiding the satellite latency and even latency incurred by slow or congested Internet connectivity to the origin server.

  • YouCache aims to reduce the network traffic because fewer requests and responses need to be transported over the link by utilising a sophisticated multicast caching system. Content is re-used and therefore the amount of bandwidth used by a client is reduced. Multicast Caching has the potential to improve the performance of the ASTRA2Connect system as it is able to benefit from documents which were fetched from other clients. Less bandwidth will be wasted for redundant transmissions like in a regular unicast-based system.
  • It will reduce the latency because any responses for requests are available immediately if the request can be satisfied from the cache. Thus, it takes less time to get the content and display it. This makes the Web more responsive. A reduced latency directly improves the user experience and may lead to a higher contentedness.

The results of the performed work will be:

  • A highly scalable youCache server supporting transparency and redundancy and operational integration in the ASTRA2Connect service platform.
  • An embedded version of the youCache client, targeted and optimized for the next generation ASTRA2Connect modem.
  • A youCache Box for the ASTRA2Connect users that serves both as pilot testing device and as add-on box for existing ASTRA2Connect users during the project's pilot trial phase.
  • A PC version of youCache client software system, compatible with the youCache embedded version, allowing for the use of the youCache service without additional hardware.

click for larger image


The core development of youCache is phased in a three-stage approach. The first step aims at careful investigation of the optimal system design and the system parameters that are relevant to achieve the best efficiency gain. This investigation focuses on calculations and simulations of layered multicast caching efficiency based on log-file of an operational ASTRA2Connect service.

In a second step existing software modules will be optimised and architecturally redesigned to be deployable as a PC based version and a set of embedded modules. A prototype system acting as autonomous layered multicast-caching box (the youCache Box) will be designed and produced based on a selected embedded system platform.

In parallel to the development the University partner will investigate and study the potential and impacts of caching on two kind of applications that have developed during the past years and that are shaping the Internet of today, video sharing like youTube and peer-to-peer file sharing like BitTorrent.

The final step will be to test the embedded youCache Box version and the PC version in a pilot trial with 20 users, where half are using the embedded and the other half the PC version.

Current status

The project successfully passed the Final Review. The Pilot has provided evidence that the implementation of a web caching strategy allows to save costly satellite bandwidth resulting in an attractive business opportunity for a satellite access provider. The pilot trials were very valuable, because important information about the system and its users have been gathered. The YouCache system, servers, PC and embedded box versions, successfully passed all major technical obstacles induced by legal requirements and have been seamlessly integrated into the A2C system. Therefore the envisaged project objectives have been achieved.

However due to the small number of trialists with different system usage behaviour, the log file data gathered during the different pilot phases were not sufficient to have high confidence in the overall bandwidth saving figures in particular when scaling up to a large end-user population.

Further development would be necessary to consolidate and improve the performance figures and to integrate YouCache in COTS client broadband routers. In addition, the improvement of the PC based client software with regard to installation and configuration of the service is envisaged. The project partners consider it also necessary to perform more accurate stress and robustness tests of the YouCache server through simulations to verify that high server load generated by a high amount of users can be managed. This further activity will allow YouCache to be in a position to plan a commercial deployment afterwards.

Hence, an extended pilot trial with at least 100 users is foreseen.