In an Multiprotocol Label Switched (MPLS) network, load balancing is the process of distributing traffic equally across label switched paths. When you have added several LSPs to the same egress router, the default behavior of the JUNOS software is to select the LSP with the lowest metric to carry all traffic. If all of the LSPs have the same metric, one of the LSPs is selected at random and all traffic is forwarded over it. You can change this default behavior by configuring load balancing on an ingress router, allowing the JUNOS software to distribute the traffic equally across LSPs.
The terms node and router are used interchangeably throughout this book.
