Netherlands VPN couldprovide

2) Adapting to connectivity changes: The connectivity between nodes may change over time as a result of networkreconfiguration or environmental changes. These changes donot happen daily, but may occur during the lifetime of thesystem. For example, network devices may be upgraded, newbuildings may degrade wireless signals, and added splittersmay degrade MoCA signals.Although we do not try to adapt the placement to smallvariations in connectivity, the placement has to adapt whenconnectivity between nodes changes significantly. To quantifythe amount of data movement caused by placement shifts fromconnectivity changes, we decrease or increase the bandwidthbetween every two nodes by up to 50%. When the connectivityis decreased, the streamability requirement is no longer met, somore replicas are needed across the neighborhood. With 50%decrease in bandwidth, bandwidth equivalent to 4.5 days ofa 10Mbps channel is needed to supply the additional replica.When the connectivity is increased, the placement does notneed to change but the current placement may have too muchreplication for the new connectivity. In our testbed, the newtarget placement would now allow to store an additional44 movies in the neighborhood. This lost opportunity Netherlands VPN couldprovide an additional 0.6% bandwidth savings on the accessnetwork. In our implementation, if this opportunity cost exceeds a certain threshold (e.g., 5%), we treat the case similarto the new node arrival case described below.3) Node additions and bootstrapping: To evaluate systembootstrapping and incremental deployment, we evaluate ascenario where a new node enters the system. We start witheight nodes in the testbed and add a new node. We use thesame topology from Figure 5. Nodes 0 to 3 and nodes 5 to 8form MoCA groups connected by coax cables. Node 4 entersthe system and joins the first MoCA group.When the new node enters the system, we assume (worstcase) that its disk is initially empty (the ISP could alternativelyship the disk seeded with some popular content). The new nodejoins the existing network and discovers neighbor nodes. Thenew node measures the network throughput to its neighbors