| 
            There are three 
            main approaches for identifying traffic to be switched: 
            
            ·        
            
            
            Path creation can be control- or topology-driven, where labels are 
            preassigned in relation to normal routing control traffic. Here, the 
            network size dictates the load and bandwidth consumed by the 
            assignment and distribution of label information. 
            
            ·        
            
            
            Request-based control traffic from protocols such as RSVP can 
            trigger path creation relating to individual flows or traffic 
            trunks. Here, the number of labels and computational overhead will 
            depend entirely on the number of flows being supported. 
            
            ·        
            
            
            Data-traffic-driven label assignment is where the arrival of data 
            recognized as a flow activates label assignment and distribution on 
            the fly. This approach implies that there will be latency while path 
            setup takes place. Overheads in this case will be directly 
            proportional to traffic patterns.   |