Monitoring enterprise voice, a component in Skype for Business or Lync which is most important. Not only collecting information about the servers and their services. Since there are users directly involved with their end devices, like phones, headset or computers. In between those components sits the network and routing devices.
Not enough here, mostlyLync or Skype for Businesswork in an environment where other voice solutions, e.g. PBX's or SIP Systems are running in parallel. During a migration for example, if you move users towards Enterprise Voice, the PBX and e.g. SIP Trunk Providers are in the loop for quite some time.