In current PPPoE daemon exist feature for session balancing by PADO-delay and some installation with multiple BRAS needs this feature.
[pppoe] pado-delay=delay[,delay1:count1[,delay2:count2[,…]]]
Specifies delays (also in condition of connection count) to send PADO (ms). Last delay in list may be -1 which means don’t accept new connections. List have to be sorted by count key.