The Challenge: The "Sea of Red" in Wireshark
When users complain that "the application is slow," network engineers are left to prove whether it's a network drop, a congested switch, or a slow server. Opening a large packet capture only to see thousands of black and red lines (TCP Retransmissions and Duplicate ACKs) is overwhelming.
Filters like tcp.analysis.retransmission only show that packets are dropping, not why. You still have to figure out if it's a duplex mismatch or a microburst.
Proving a latency bottleneck requires manually plotting tcptrace I/O graphs, calculating Round Trip Times (RTT), and comparing sequence numbers by hand.
"Users blamed the network for database timeouts. Wireshark showed a 40% retransmission rate, but graphing the sequence numbers to prove it was a server-side window size issue took me half the day."
The Solution: Automated Performance Dashboards
Pcap AI eliminates manual TCP stream tracking. By uploading your capture, the ML engine instantly calculates global metrics and isolates the specific endpoints responsible for the congestion.
- ✦ Retransmission Scoring: Instantly calculates global and per-endpoint packet loss rates (e.g., highlighting a critical 15% retransmission rate on a specific VLAN).
- ✦ Network vs. Application Latency: Automatically differentiates between slow network links (High RTT) and slow server application responses (Zero Window / Window Full events).
- ✦ Microburst Detection: Identifies sudden spikes in throughput that overwhelm switch buffers, causing massive temporary packet drops.
- ✦ Clear Evidence: Generates a clean, boardroom-ready PDF proving exactly why the application is slow, ending the "finger-pointing" between DevOps and NetOps.
Wireshark Manual Analysis vs. Pcap AI
Manual (Wireshark)
Configuring tcp.analysis filters, exporting tcptrace graphs, and manually calculating RTT averages. Process takes 1–3 hours.
Pcap AI
Automated throughput, latency, and retransmission calculation per flow. Process takes less than 20 seconds.
*Based on a 1GB PCAP file with dense enterprise application traffic.
Frequently Asked Questions
How do you find TCP retransmissions in Wireshark?
Network engineers typically use the filter tcp.analysis.retransmission or tcp.analysis.fast_retransmission. However, this only filters the packets. Pcap AI automatically analyzes these packets to calculate exactly what percentage of traffic is failing and points directly to the offending IP pair.
What causes a TCP retransmission storm?
A TCP storm occurs when packets are dropped in transit, forcing the sender to resend them repeatedly. Common causes include congested switch buffers, faulty Ethernet cables, duplex mismatches, or an overloaded firewall dropping states.
AI Analysis Output (Sample)
