Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


Traffic Flows Before Load Balancing



The following sample output illustrates the details to look for when you issue different show commands to check if traffic is balanced. The following output is before load balancing is configured and is taken from transit router R2 in the network shown in Load-Balancing Network Topology.


To check the distribution of traffic across interfaces and LSPs, use the following CLI operational mode commands:

Sample Output 1

Sample Output 2

Sample Output 3


Sample Outputs 1 through 3 from transit router R2 show that traffic is not balanced across LSPs or interfaces.

Sample Output 1 for the show route command shows that all LSPs have the same metric (1) to the destination, even though they are traversing different interfaces. lsp1 and lsp4 are using so-0/0/1, while lsp2 and lsp3 are using so-0/0/2.

Sample Output 2 for the monitor interface traffic command shows that traffic is not evenly balanced across interfaces so-0/0/1 and so-0/0/2. Almost all traffic is going out so-0/0/2.

Sample Output 3 for the show mpls lsp statistics command shows that traffic across LSPs is not balanced. All traffic is going over lsp1.

Related Topics

For additional information about MPLS fast reroute and MPLS protection methods, see the following:

  • Junos User Guide

  • Junos MPLS Applications Configuration Guide

  • Semeria, Chuck. RSVP Signaling Extensions for MPLS Traffic Engineering. White paper. 2002

  • Semeria, Chuck. IP Dependability: Network Link and Node Protection. White paper. 2002

  • RFC 4090, Fast Reroute Extensions to RSVP-TE for LSP Tunnels

The Junos OS uses the load-balancing function across different protocols and features. For information about other types of load balancing, see the following:

  • Option: Optimizing VPLS Traffic Flows, Junos User Guide

  • Protocol-Independent Load Balancing for Layer 3 VPNs, Junos VPNs Configuration Guide

  • Load Balancing Among Multiple Monitoring Interfaces, Junos Services Interfaces Configuration Guide