In a connection-oriented network, a source network node responds to a connection request from a source user by sending signaling messages to adjacent nodes to request reservation of multiple paths by specifying a QOS parameter of minimum level and then establishes to a destination node if the...http://www.google.de/patents/US5832197?utm_source=gb-gplus-sharePatent US5832197 - Alternate routing by increasing initially low QOS value of a selected alternate path during failure to user-specified value 
