Bridge Filter Connection limit

Hey,
I have setup a bridge [ MT] beween main router and customer LAN. - Customers use PPPOE to log in.
We have observed PPPOE Flood and want to limit using bridge level connection limit.

Could anyone help how can i limit it.
Cuurently below are rules

0 X chain=forward action=log
src-mac-address=00:00:00:00:00:00/FF:FF:FF:FF:FF:FF mac-protocol=ip
packet-type=host limit=1,5 log-prefix=“dams”

1 chain=forward action=log mac-protocol=pppoe-discovery
packet-type=broadcast limit=25,5 log-prefix=“br0_”

2 chain=forward action=accept mac-protocol=pppoe limit=75,5

3 X chain=forward action=drop mac-protocol=pppoe-discovery
packet-type=broadcast limit=75,5

I am not sure How limit works? I want to limit per second only 25 pppoe-discovery messages should be allowed.

THis is for overall customers.
Also I am not sure different between pppoe-disconvery and pppoe-session protocols.
Would also like to set per session OR per mac pppoe /PPP max allowed pppoe-discovery/pppoe-session messages.