Hello Diessi
If you have unequal EIGRP load balancing across three Ethernet links, and you are using CEF, the default behaviour is to load balance based on destination. This will indeed function, but it is not always the best choice.
Let’s say you have load balancing on these three links with a ratio of 3:2:1. Let’s say you have 60 destinations being routed in a particular period of time. You will have 30 destinations going through one route, 20 going through another and 10 through the third regardless of what the actual traffic for each destination eventually becomes. Once each destination IP is encountered by the router for the first time, it will be routed based on this load balancing algorithm. This is how CEF functions by default. The more destinations there are, the more efficient this process is. You can also see that this is not very effective for traffic with very few destination IP addresses such as two or three.
You can of course modify this default behaviour of CEF by implementing per-packet load balancing as you suggested as well.