I want to stop the re routing of links while dragging a node in the layered layout
Well, I hope it is clear that when you move one node relative to another node with which it is connected by a link, the link needs to be re-routed in order to maintain the appearance of a connection between the two nodes. Otherwise there would be gaps between links and their connected nodes.
You might want to set Link.adjusting to some value. The value will depend on what kind of routing is happening and what aspects of the old route you want to keep.