Category: MPLS TE
One of the most commonly asked load-sharing-related questions is “can I load-share traffic across unequal-cost links?”. In general, the answer is no. In order to load-share the traffic, you need more than one path to the destination and the only way to get multiple routes toward a destination in the IP routing table is to make them equal-cost (the only notable exception being EIGRP that supports unequal-cost load-sharing with the variance parameter).
There are, however, two cases where you can force unequal traffic split across equal-cost paths toward a destination: when using inter-AS BGP with the link bandwidth parameter, and when using unequal-bandwidth traffic-engineering tunnels.