CHAPTER Mobility and Heterogeneity 13 Using mobile devices as peers in an overlay introduces the possibility of increased churn due to frequent roaming transitions that such devices experience. Possible solutions discussed in this chapter include using mobility support in the native layer, virtualizing such support in the overlay itself, or restricting the role of mobile devices as peers. In addition, mobile devices and other networked con- sumer electronics introduce a degree of resource heterogeneity into the peer population. Adaptability to heterogeneous peer conditions is the scope of another category of P2P overlays called variable-hop overlays, which are discussed here.