01648nas a2200157   4500000000100000008004100001260002000042100002900062700001700091700002000108700001700128700001600145245004800161856005800209520122300267       2017                            d  aCalabria, Italy1 aEmmanouil Dimogerontakis1 aRoc Meseguer1 aLeandro Navarro1 aSergio Ochoa1 aLuís Veiga00aCommunity Sharing of Spare Network Capacity  uhttp://people.ac.upc.edu/leandro/pubs/icnsc-acc17.pdf3 aIn several community scenarios, people share benevolently their spare broadband Internet access connectivity with other people who cannot afford it. Although laudable, this sharing process can negatively affect the service received by the primary users, thus jeopardizing the continuity of this community service. In this paper we propose the use of a gateway that separates the traffic of the primary users from that of the secondary users, the beneficiaries of this sharing. We analyze the impact and behavior of several mechanisms for using this gateway, to determine how to maximize network utilization, use of the excess network capacity, and minimize the impact on the primary traffic. As a result we present a set of lessons learned and recommendations. Particularly, some strategies that use tunneling for managing the primary and secondary traffic achieve the best performance isolation for the primary user, while the secondary user obtains the spare capacity equivalent to non-differentiated best effort, with a limited penalty (around 20%). Combined with complementary queueing techniques (instead of FIFO), other important flows for the user experience (such as DNS or ICMP) can be practically unaffected.