A communications network including nodes which permit networks to be tunnelled across intermediate networks. The present invention has application, in particular, to SDH networks, SONET and OTN. The content of entities for transportation across an existing network are mapped into a series of subframes...http://www.google.com/patents/US7539196?utm_source=gb-gplus-sharePatent US7539196 - Method and apparatus for tunnelling data in a network
