The NEMO basic support specification is not limited to a single level of mobile networks attaching to the stationary Internet. Rather, arbitrary levels of nested mobile networks are supported, employing for each level of nesting the same attachment, encapsulation and tunnelling mechanisms. With arbitrarily deep nested mobile networks, paths taken by data traffic can be extremely sub-optimal both inside the nested topology through successive mobile routers, and outside the nested topology, through successive Home Agents over the Internet. Moreover, the overhead incurred through tunnelling and encapsulation of data traffic can become prohibitively large. This document analyses the scenarios in which these problems are particularly acute.