Load Balancing is a method aiming to spread traffic across multiple links to get better link usage. This can be done one per-packet or per-connection basis.
You have Dual Wan connection and you want to create a link failover? In case, link to WAN1 goes down and link to WAN2 becomes active, you simply have to configure routes: Two gateway failover
This method uses firewall packet marking to select one from multiple gateways.
- Per-Traffic Load Balancing
- Load Balancing over Multiple Gateways
- Manual:Load balancing multiple same subnet links
ECMP (Equal Cost Multi-Path)
This method uses multiple gateway with same cost.
PCC (Per Connection Classifier)
- NTH load balancing with masquerade
- NTH load balancing with masquerade (another approach)
- Manual:NTH in RouterOS 3.x
Can combine multiple links to achieve: higher speed, failover, load balancing.
More detailed information about "bonding" you can find here: Manual:Interface/Bonding
Two or more links are setup with dynamic routing protocol OSPF with equal cost. Then equal multipath routing is used.
- Manual:Route Selection Algorithm in RouterOS#Load balancing and dynamic routing protocols