Snort repot - 1000+ alerts in a short time on port 5060

i woke up this morning and could see over 1000+ of these alerts and they

They came in the time space 23:34 - 23:35

Can anybody tell me what that was about and should i be worried for an eventual ddos attack ?

I am running pfsense and behind that box i have my lan and a nic where my server is in a separate environment.