Aviz Networks details ASN-DPI SIP and RTP metadata for VoIP troubleshooting

Aviz Networks describes ASN-DPI, an agentless approach that exports deep SIP and RTP metadata to help enterprises troubleshoot VoIP issues by separating call signaling from media quality and correlating both in real time.

Research Overview

The blog frames real-time voice troubleshooting as difficult because SIP is responsible for call setup while RTP carries the audio stream, and conventional monitoring may not interpret both protocols with sufficient context.

ASN-DPI is presented as a network-level method that extracts and correlates SIP and RTP metadata as traffic traverses enterprise networks, without exposing voice payloads or deploying endpoint agents.

Key Findings

The approach targets visibility gaps in VoIP troubleshooting where flow-level monitoring and synthetic probes provide limited detail about codec negotiation, signaling failures, and media path behavior.

The blog states that ASN-DPI exports SIP metadata for call negotiation and RTP metadata for media delivery and quality metrics, then links the two to support end-to-end call lifecycle analysis.

Technical Breakdown

For SIP, ASN-DPI extracts fields used to track calls and validate negotiated media behavior, including the SIP Call ID, uplink and downlink traffic direction, media count from SDP, media type, RTP transport protocol, and media IP address and port.

The SIP metadata also includes supported format counts and payload format identifiers such as codecs including G.711 and comfort noise, which the blog says supports identifying misconfigurations involving firewalls, NAT, SBCs, and UC platforms.

Operational Impact

For RTP, the blog says ASN-DPI continuously computes quality metrics from exported RTP metadata, including packet loss affecting clarity, jitter measured in milliseconds, out-of-order packets caused by network reordering, and duplicate packets indicating retransmissions or anomalies.

It adds that these metrics help teams determine whether voice problems relate to congestion, WAN instability, QoS misconfiguration, or infrastructure faults, while correlation between SIP and RTP provides a single view of signaling and media performance.

Leadership Perspective

The blog positions agentless deployment as a factor in operational adoption, stating that ASN-DPI works passively at the network level and does not require agents on endpoints.

It also describes metadata-only monitoring as addressing privacy and compliance considerations by avoiding export of call audio payloads while still providing codec, timing, sequence number, jitter, and loss information needed for troubleshooting.

Overall, the blog’s central point is that ASN-DPI enables enterprise VoIP troubleshooting by exporting SIP and RTP metadata, correlating them using a shared session identifier, and computing RTP quality metrics without payload exposure or endpoint agents. Blog Signals brief is a fact-based summary of the vendor blog.