This article provides confirmation that EX4400 platform does not support MC-LAG.
##
## Warning: configuration block ignored: unsupported platform (ex4400-24x)
multi-chassis {
multi-chassis-protection 10.0.0.2 {
interface ae1;
}
mclag is not supported in EX4400
You can check the supported platforms for MCLAG in the below link:
https://apps.juniper.net/feature-explorer/feature-info.html?fKey=4070&fn=Multichassis+link+aggregation+%28MC-LAG%29
You can also check the supported features on the EX4400 in the Feature explorer tool:
https://apps.juniper.net/feature-explorer/
8/1/2023: KB created