Annotated Call Flows

Hand-annotated protocol call flows rendered from Wireshark PCAPs by VisualEther. Each opens an interactive sequence diagram with a per-message explanation on every arrow.

• The Life of a 5G Connection, One Packet at a Time (5g)
• Retrieve UE Context over Xn: RRC Resume, Message by Message (5g)
• EN-DC SgNB Addition over X2: Grafting a 5G Bearer onto LTE (5g)
• EN-DC SgNB Addition Acknowledge over X2: The Reply, Carrying CG-Config (5g)
• A 5G NSA Attach, End to End: From LTE Random Access to a Measurement-Triggered 5G Leg (5g)
• Inside F1-U: NR-U Flow Control Between the gNB's CU and DU (5g)
• Reconstructing a VoNR Voice Call from a Bare srsRAN F1-U Capture (5g)
• A 5G NR Attach on the Air Interface, Layer by Layer (5g)
• What the NEA2 Keys Unlock: Deciphering a 5G NR Radio Capture from RRC to IMS (5g)
• RLC-NR Acknowledged Mode in a Real 5G Capture (5g)
• RLC-NR Acknowledged Mode on the Data Bearer (5g)
• MAC-NR in a Real 5G Capture: Contention Resolution, LCID Multiplexing, and Buffer Status (5g)
• PDCP-NR in a Real 5G Capture: Sequence Numbers, COUNT, and Where Ciphering Happens (5g)
• PDCP-NR on the Data Bearer: 18-bit Sequence Numbers and the Deciphered Payload (5g)
• SDAP in a Real 5G Capture: QoS Flows, the QFI, and the Data Radio Bearer (5g)
• NR-RRC in a Real 5G Capture: Setup, Security, Reconfiguration, and Release (5g)
• NAS-5GS in a Real 5G Capture: Registration, Service Request, and What Stays Ciphered (5g)
• Inside F1AP: A UE Registration Across the 5G CU/DU Split (5g)
• A BGP Peering, Packet by Packet: From TCP Setup to Converged Hub-and-Spoke Routes (routing)