Overview

Traditional static load balancing does not consider the utilization of each member link within the load-balancing group, leading to uneven load distribution among the member links. This issue becomes more pronounced with the appearance of large data flows, exacerbating congestion on the selected member link and potentially causing packet loss.

By enabling dynamic load balancing, the traffic of Equal-Cost Multi-Path (ECMP) routing can be distributed across different member links through dynamic load balancing, maximizing load balancing among the member links.

Implementation Principle

PICOS supports Normal mode of Dynamic load balancing.

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The device forwards the packets based on the flowset, selecting the member link with the lighter load for forwarding. Packets within the same flowset are forwarded using the same member link.

Restrictions and Guidelines

When you configure Dynamic Load Balancing, follow these restrictions and guidelines:

• Dynamic Load Balancing for ECMP is only supported on Trident3 and Tomahawk3 platforms.

• When the ECMP hash-mapping mode configuration (set/delete) changes, a system restart reboot is required for the configuration to take effect.

• ECMP hash-mapping modes (round-robin-load-balancing, randomized-load-balancing, symmetric and dlb-normal)are mutually exclusive. To switch between modes, you must first delete the configured mode before setting up the new one. Then, restart the system for the configuration to take effect.

Configuring Dynamic Load Balancing

Procedure

Step 1         Enable normal mode of Dynamic Load Balancing for ECMP (Equal-Cost Multi-Path Routing).

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commit

Step 3         Under Linux shellCLI operational mode (prompted with “>“), run the following command to restart the system for the configuration to take effect. sudo systemctl restart picos

request system reboot

Configuration Example

• The following commands enable normal mode of Dynamic Load Balancing for ECMP.

admin@PICOS# set interface ecmp hash-mapping dlb-normal
admin@PICOS# commit
admin@PICOS# exit
admin@PICOS> startrequest shell sh
admin@PICOS:~$ sudo systemctl restart picossystem reboot

Verify the Configuration

• Use the command run show route ipv4 to view the ECMP routes. In the following show result, we can see that the destination address 10.20.51.0/24 is reached via three different next hops: 192.168.0.1, 192.168.1.1, and 192.168.2.1, forming ECMP routes.

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