Hi, Mikrotik team!
Please expose more ARP settings for being configurable, specifically that, which have impact of ARP request sending frequency:
net.ipv4.neigh.default.retrans_time_ms
retrans_time_ms (since Linux 2.6.12)
The number of milliseconds to delay before retransmitting
a request. Defaults to 1000 milliseconds.
net.ipv4.neigh.default.gc_stale_time
gc_stale_time (since Linux 2.2)
Determines how often to check for stale neighbor entries.
When a neighbor entry is considered stale, it is resolved
again before sending data to it. Defaults to 60 seconds.
Why it needed and wich problems it may solve:
When Mikrotik device is used for termination connected networks with many addresses (ISP BRAS/EDGE router), especially networks of public routable addresses, like /24 or /22, and there are not so many alive hosts in this networks, then it causes the much amount of broadcast traffic, because public addresses in Internet being scanned and accessed the whole time
Moreover things going wild when it is “unnumbered” Cisco scheme analog, where many vlans bridged, and network terminated on bridge, then ARP flood increasing drastically
Exposing these sysctls will help to reduce the amount of ARP requests in this cases
I think the best way is to do it in manner wich already used for ARP - globally and per interface, as it designed in Linux already
Maybe the better idea is expose all settings related to Linux ARP stack, idn, but these two look very helpfull in some situations
Thank you!