If all I need is L2 bridge would there be any reason to keep arp enabled on bridged interfaces?
Similarly, why proxy-arp is available for interface that is a part of a bridge - isn't it redundant

(ROS4.2)
thanks,
Michael

As soon as you add interface to the bridge forget about any options of those interfaces - only bridge options matters. If there is no IP on the bridge itself and there is no need to communicate from the bridge to any other device - you can disable arp

yep, all those settings are necessary only if you need routing between that bridge and some other interfaces. for true bridging, they don't play any role

Based on your answers it looks that MT can do routing and bridging at the same time and two functions are exclusive of another. Good to know!

Thank you all for the information.

regards,
Michael

basically, bridge simply sends packets from one bridge port to another ports of the same bridge. as soon as bridge receives packet with its MAC address as destination, packet either goes to the router itself (if dst-IP is router's IP), or is being routed to another interface (ethernet, vlan, another bridge, tunnel, etc.)