iproute2 load balacing

 hello all,
I have doubts about the management of the multipath with iproute2.

In particular, do not understand how is the distrubution of traffic between two gateways.

Use this command ip route add default scope global nexthop via 192.168.1.1 deveth1 weight 1 nexthop via 10.64.64.64 dev ppp0 weight 1

Actually I see that some servers will reach from 192.168.1.1, others from10.64.64.64, but I do not understand the logic that uses this command.

Can you help me understand?

Tnx.