Description

This article provides explanation to how load-balancing works on SRX devices.

Symptoms

When ECMP is configured on SRX devices, the packet distribution among the interfaces is not even.

Solution

SRX performs load-balancing on per-flow basis and not per-packet basis.

Based on the hash calculated from the tuples, SRX will select anyone of the next hops from the forwarding table. As such, one particular interface could be handling more traffic than the rest. Please refer to the below document for information regarding the working of ECMP on SRX devices-

ECMP Implementation for Junos OS SRX Series Firewalls and vSRX Virtual Firewall Instances

Modification History

2024-09-29 : Article Created