Kihong Story Lab

KIHONG STORY LAB · PRACTICAL LEARNING Registration, session establishment and a successful application response are three different outcomes. Here is how I keep them separate. A UE appears registered, but its application cannot exchange data. My first question is not “which side is broken?” It is “what does this trace actually establish?” Registration success does not, by itself, prove that a PDU Session or a working service path exists. Video walkthrough Watch the 5G troubleshooting walkthrough: registration, PDU Session and service evidence. A small case with an important missing fact This instructor-authored teaching example contains an established RRC connection, Registration Accept, Registration Complete in this particular case, and a PDU Session Establishment Request. Application data is unavailable. The supplied extract does not show a matching Accept or Reject, and its capture completeness is unknown. Observed: a session request was recorded. Not established: the matching r...

KIHONG STORY LAB · PRACTICAL LEARNING A smoother sentence can weaken a story, and an EPUB file can exist without working for its reader. I check the result at both stages. When an agent says “revision complete,” I still have an editorial decision to make. Did it preserve the reason for a character's action? And when it says “EPUB saved,” can a reader actually reach the right chapter? The saved result is my acceptance test. Video walkthrough Watch the manuscript-to-EPUB walkthrough: compare the revision and inspect the actual book. One sentence, different personal stakes In my novel example, the earlier version starts Dohyeon's training the day after Mijeong finishes her handover. The revised version begins the schedules together. That is a small sentence with a larger effect: it changes what Dohyeon stands to gain and the reason behind a later avoided phone call. I compare the intention and the connected chapters, not just whether the revised wording reads smoothly. The video ...

Vibe Coding from Zero: Build Your First Web Page & Game A step-by-step English course for complete beginners, built around my real setup and workflow. Never written code or used a terminal? Start here. Learn to build your first web page and a small game with AI, one step at a time. You have an idea for something useful. What do you install, where do you type, and how do you know it actually works? Those are reasonable first questions. My new English Udemy course, Vibe Coding from Zero: Build Your First Web Page & Game , takes you through them one step at a time. No previous coding experience is required. Watch the 52-second course preview Watch the preview on YouTube Start with the steps that make the rest possible Built around my real setup and working routine. I explain the initial setup and the environment I actually use for AI-assisted work, with a Mac mini as the main computer. The course then connects that starting point to the way I create, check, save and resume pr...

Your resume gets you into the room. Can you explain what you actually owned? A project can look impressive on a resume and still be difficult to discuss in an interview. What did you decide? Which evidence supported that decision? What changed because of your contribution? Those questions require more than a polished summary of what the team delivered. I am Kihong Kim. I bring 25 years of experience in mobile communications and firsthand experience across more than 100 job interviews, including Apple's final stage and Google TPM interviews. I built Big Tech Interview Fast Track: Engineers & TPMs to help candidates turn their own work into clear, role-focused interview answers. One project, two different interview conversations One of my examples comes from work on South Korea's first iPhone commercial launch. During early iPhone 3GS interoperability testing, issues included supplementary calling services that did not work correctly and call drops in particular areas. W...

  A connected-call indicator does not prove that usable audio is reaching the listener. I separate three questions: was the session established, what media conditions were negotiated, and what packets actually arrived? That separation helps narrow down a VoLTE no-audio problem without guessing the cause. 1. Which request received the 200 OK? SIP controls session establishment, modification, and termination. A 200 OK for REGISTER is different from a 200 OK for INVITE. Identify the call using its Call-ID and CSeq, then correlate the successful INVITE response with its ACK. This is evidence about call setup; it is not evidence that speech reached either listener. 2. Read SDP as receive destinations and media conditions Compare the offer and answer currently in effect: audio receive addresses, ports, codecs, and direction. If an UPDATE or re-INVITE changed the session, the initial SDP alone is insufficient. c= : connection address. A media-level c= overrides the session-level add...