I am not sure I can answer that as I have never heard of the Libelium mesh. What I can tell you is what I know about the Digi Mesh protocol.
The Digi Mesh protocol is a true peer to peer protocol unlike the Zigbee mesh. That is to say, providing you have the same channel and PAN ID, you can send data to any node within a network via other nodes which are acting as routers. (In most cases, all nodes in a Digi Mesh network are routers), however, you do have options that can change that in a Digi Mesh network that will allow you to configure nodes as sleeping routers or sleeping end devices.