We have many Uniview and Microdigital cameras. ipc324sb-DF28K-i0, MDC-M8040FTD-30 ...
The cameras generate a lot of traffic at 255.255.255.255.
A packet from Wireshark for example:
42 2022-03-24 15:33:23.608671 192.168.0.22 255.255.255.255 IPv4 1514 Fragmented IP protocol...