slave server 104 and then to regional hubs 106 are primarily unidirectional however there will always be bidirectional traffic as client status and content upload information must make its way back to the central server 102 as will be shown in the following parts of this specification varying combinations of p2p clients will be located in compartmentalized groupings referred to as local clusters 110 these local clusters 110 are typically defined as any group of clients sharing a common local gateway beyond their isp and will usually but not always consist primarily of wireless devices because of the variance in the type of clients within a given cluster 110 it is important to be able to identify the strongest clients within each cluster 110 with regard to the external connection to the network 114 and to other strong clients within the cluster 110 since the different clients within a local cluster 110 will have varying bandwidths and capabilities the codec used as will be later seen will treat the clients as being located in different tiers according to their respective bandwidths and strengths referring again to fig1 clients 120 and 122 have been arbitrarily classified by the codec as first tier clients because their bandwidths and strengths are greater than other clients within the cluster 110 and more likely to be able to supplement any weaknesses of other clients within the cluster 110 similarly clients 124 and 126 have been classified by the codec as more likely to be able to supplement any needs of the remaining clients within the cluster clients 128 and 130 as.