TOPIC
Computer networks
These are the same questions found in the library, grouped here by the capability each one mainly examines.
18 questions
A · Professional problem solving and implementation18
- After a page sits idle, the first request is much slower than later ones. What network-level causes could explain it, and how would you tell them apart?
- The first screen of an image-heavy page opens slowly. How would you work backwards from the symptom to the cause, and what would each improvement cost?
- A request calls four downstream services, each using a full two-second timeout. End-to-end tail latency is high, and clients continue work after the response is no longer useful. How would you propagate deadlines and budgets?
- The system uses pre-signed URLs for private downloads, but links can be forwarded or retained for a long time. How would you design authorization and expiry boundaries?
- How should the loading and request strategy of streaming media be designed so it starts fast and does not stall? How do you trade off segmenting, adaptive bitrate, preloading, and caching?
- API latency rises while database CPU remains low, and application logs show connection waits. How would you distinguish connection leaks, an undersized pool, and slow transactions holding connections?
- A service has moved to a new address, but some users still reach old nodes and recovery varies by network. How would you check DNS caches, client caches, and existing connections?
- After an update, some users occasionally load new HTML with old JavaScript and the page fails. How would you design asset naming, cache policies, and release order to reduce inconsistency?
- The page HTML arrives quickly, but users still wait a long time to see the main content. How would you trace blockers across resource discovery, download, parsing, execution, and painting?
- A service’s resident memory is stable, but major page faults, disk I/O, and tail latency rise together. How would you distinguish changes in the working set, mapping behavior, memory pressure, and application access patterns?
- Clients report occasional request timeouts while server processing time looks normal. How would you use TCP retransmissions, RTT, and connection state to locate where the delay occurs?
- A multi-tenant platform must send event notifications (webhooks) to customer systems. How would you design delivery and retries when a client is unavailable for a long time?
- After deployment on a multi-socket machine, threads move across NUMA nodes and memory latency varies. How would you investigate using CPU affinity, memory placement, and scheduling behavior?
- After certificate rotation, short connections work, but some clients fail a handshake when reconnecting or resuming after a long-lived connection closes. How would you distinguish certificate-chain, resumption, connection-pool, and client-cache effects?
- When a mobile device switches from Wi-Fi to cellular, some HTTP/3 requests fail while the session still appears online. How would you investigate path migration, timeouts, and middlebox behavior?
- A program writes a data file before updating its index, but after a power loss the index points to incomplete content. How would you analyze write ordering, flush semantics, and recovery?
- A feature works on the corporate network and most home networks, but requests often time out on a particular carrier or under poor connectivity; server error rates do not rise at the same time. How would you isolate causes across client, network path, protocol, and retry behavior?
- Instance health checks verify only process liveness, while user requests fail on a critical dependency timeout. Adding every dependency to probes may remove all instances. How would you design this?
No questions in this section match your target. ·