What is an indicator of network congestion in VoIP communications?

Network congestion leads to variable delays in packet delivery, which manifests as increased jitter in VoIP communications, causing audio quality degradation. Jitter is a direct symptom of inconsistent packet arrival times due to an overwhelmed network path.

Video loss due to frame corruption primarily indicates issues with video codecs or media processing, not directly network congestion.

While gaps in voice due to packet loss are a severe symptom, jitter increase is an earlier and more fundamental indicator of congestion impacting VoIP's real-time nature.

Discards in router/switch interfaces are network-level indicators of congestion, but jitter is the specific manifestation of this congestion within the VoIP media stream itself.