SRW / SGE switches are sending packets like this below:
IP 172.16.57.100.1900 > 126.96.36.199.1900: UDP, length 296
IP 172.16.57.100.1900 > 188.8.131.52.1900: UDP, length 313
(a discovery message to the multicast address 184.108.40.206 on port 1900 via the UDP protocol)
Can this behaviour be disabled ?
It looks like this is for uPnP.
This is normally coming from a windows machine, are you sure that it is coming from the switch?
For the switch, here is an admin guide:
These are platform specific, however you basically need to disable upnp if it is a bother to you. It is harmless for the switch to send however if you simply want to ignore it.