This solves the second problem. For example, Figure 6 shows that, if the total traffic from router C1 to router B1 is 160 Mbps, and the traffic from C2 to B1 is 90 Mbps, then two LSPs can be configured from C1 to B1. Their load ratio is automatically derived from their bandwidth specification. With MPLS, CBR and enhanced IGP, not only can load sharing be done between two paths of different cost, but load ratios can be specified as desired. With IGP shortest-path routing and ECMPs, the problem cannot be solved.
Network administrators can use ERs to control traffic trajectory precisely.
Backup LSPs can be used to provide graceful degradation if a router or link fails. Problems that were difficult to solve before, can now be solved easily. More customers can be added to the network without affecting network performance. Revenue is, therefore, increased. The network is, therefore, more adaptive and robust, and management complexity and associated costs are reduced.