Browser-based PCAP Analyzer
Not animations — actual engineering tasks. Open realistic 3GPP traces, read the NGAP/NAS-5GS/PFCP/HTTP-2 layers, and find the root cause. Every lab is graded and teaches you the spec as you go.
Available PCAP labs
5G Registration Failure — Metropolitan Region
A UE in a metropolitan deployment region keeps failing 5G registration. Analyze the NGAP/NAS-5GS trace, find the 5GMM reject cause and decide whether the fix lives on the UE or the network.
RACH Failure — Debugging Preamble / Msg1–Msg4
A UE cannot access an airport macro cell. Walk through the 4-step contention-based RACH procedure, find where Msg1/Msg2/Msg3/Msg4 breaks down and decide the correct PRACH preamble format for the cell radius.
VoNR Call Setup — Successful End-to-End
A VoNR call is working perfectly — now understand what is happening under the hood. Trace the SIP/SDP offer-answer, the P-CSCF to PCF policy authorization, the NGAP PDUSessionResourceModify that creates a dedicated 5QI=1 QoS flow, and the RTP media that finally flows on it.
5G PDU Session Establishment — Find the QoS Flow Setup Failure
An industrial-automation UE authenticates fine but cannot open a data session. Trace the SBI + N4/PFCP signalling between AMF, SMF, UDM and UPF to find whether the fault is a policy misconfiguration or a UPF capability mismatch.
SUCI / SUPI Privacy — Tracing Subscriber Privacy in 5G
A researcher claims 5G finally closes the IMSI-catcher loophole. Walk through a successful registration and verify it for yourself: the UE sends SUCI (not IMSI) on the air, UDM/SIDF decrypts it inside the core, and SUPI only ever appears on SBI traffic.
IMS VoNR Registration Failure — Debugging a SIP 401 Loop
A specific device model cannot place VoNR calls. The 5G attach and IMS PDU session come up cleanly, but IMS registration bounces forever with 401 Unauthorized. Walk through the SIP trace between the UE, P-CSCF, I-CSCF, S-CSCF and HSS, and find the IMS AKA algorithm mismatch (RFC 3310 vs RFC 4169).
Network Slicing End-to-End — Trace a Slice Selection
An enterprise UE requests two simultaneous slices (eMBB + URLLC). Trace how NSSF negotiates Allowed NSSAI and how each slice is served by a different SMF and UPF, confirming control- and user-plane isolation.
5G Xn-based Handover — Why Did It Fail?
A premium UE on a highway connecting Munich Airport to the city drops every time it crosses between two neighbouring gNBs. Both gNBs are connected to the same AMF and SMF, and Xn is up. Read the Xn-C (SCTP/XnAP) and NGAP trace to find exactly where the handover breaks and why — a slice-aware mobility bug hiding in plain sight.
N2 (Inter-AMF) Handover Failure — What Went Wrong?
A UE crossing a TA boundary between two AMF sets gets stuck mid-handover. Source and target AMFs exchange Namf_Communication on N14, UDM is queried, and something comes back empty. Find the root-cause packet and decide what the NOC has to change.
5G Roaming (Home-Routed) — Tracing SEPP and N32
A roaming subscriber gets intermittent data service. Trace the N32-c and N32-f signalling between V-SEPP and H-SEPP, find the PRINS policy violation and decide on the architectural fix.
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