RTNICDiag Case Studies: Solving Common Network Problems

How to Use RTNICDiag for Real-Time Network Diagnostics

What RTNICDiag Does

RTNICDiag is a real-time network diagnostic tool designed to monitor, analyze, and help troubleshoot network behavior as it happens. It collects live interface statistics, packet flow summaries, latency metrics, error counters, and protocol-specific logs so you can pinpoint faults quickly and validate fixes immediately.

When to Use It

• Active outages: isolate affected segments and identify root causes.
• Intermittent issues: capture transient errors and correlate them with configuration or traffic changes.
• Performance tuning: measure latency, jitter, and throughput under load.
• Post-change validation: confirm that updates didn’t introduce regressions.

Quick Setup

1. Install: Deploy RTNICDiag on a host with network visibility (edge router, span/mirror port, or collector).
2. Permissions: Ensure it has the required privileges to access interfaces and packet capture (root or equivalent).
3. Configuration: Specify interfaces to monitor, capture filters (BPF), log destinations, and retention.
4. Start in live mode: launch the daemon or CLI with the real-time flag to stream metrics and captures to console or a monitoring backend.

Core Commands and Modes

• start/live: begins real-time monitoring on specified interface(s).
• capture[duration]: captures packets matching a BPF filter for the duration.
• stats [interval]: prints interface and flow statistics at the given interval (default 5s).
• errors: shows counters for CRC/frame errors, drops, overruns.
• latency : measures round-trip and one-way latency for a specified flow (IP/port pair).
• flows [top N]: lists top N flows by bandwidth or packet count.
• export : saves current captures/stats (pcap, CSV, JSON).
• diag-report: generates a compressed diagnostic bundle for offline analysis or vendor support.

Interpreting Key Outputs

• Interface utilization: sustained near-100% indicates congestion — check buffers and QoS.
• Error counters: rising CRC/frame or MAC errors point to physical layer issues (cabling, SFPs).
• Drops: drops on rx path usually indicate buffer exhaustion or misconfigured NIC offloads.
• High latency/jitter: look for queuing, overloaded links, or asymmetric routing.
• Burst flows: unexpected top talkers may indicate misbehaving hosts or DDoS; correlate with flows list.

Troubleshooting Workflow

1. Baseline: run stats and flows to understand normal behavior.
2. Isolate: use capture filters and flows to narrow affected subnets/hosts.
3. Correlate: match RTNICDiag captures with system logs, interface counters, and change events.
4. Hypothesize: form a cause (e.g., duplex mismatch, faulty NIC).
5. Test: apply targeted changes in a controlled window and observe RTNICDiag outputs live.
6. Validate: confirm resolution via sustained metrics improvement and reduced errors.

Best Practices

• Use BPF filters to