In case you run cisco devices you may do this on your switches/routers and just do the alerting in checkmk. I recommend that to our CC LAN but until now no interest, so I have no rea experience with it but curious how it works.
To have a clear view of jitter on your network for voip or multimedia for me it would not be sufficient too just do some ping from the monitoring server to some other hosts.
May also help could ntop:
It has an integration in checkmk but costs extra money.
regards
Michael