TCP: connections · routine

One round trip, not three

Four requests to the same host. Make each of them cost a single round trip on the wire — the handshake is not free and you should only pay it once.

How this is graded

Every request returns successfully inside 60 ms
Opens at most 1 connection
Costs at most 0 round trips per request

The budget is measured, not chosen: it is what a configuration that solves this actually cost, plus a little room.

The client

Timeouts

connectTimeoutMsGetting a connection, handshake includedreadTimeoutMsIdle time waiting for bytes; restarts when some arrivetotalBudgetMsThe whole request, every retry and backoff included

Retries

maxAttemptsIncluding the first. 1 means no retriesjitterHow the delay is spread across clientsrespectRetryAfterWait as long as the server askedgenerateIdempotencyKeysAttach a key to non-idempotent requestshonourIdempotencyKeyRetry a non-idempotent request that carries oneretryPostTreat POST as safe to repeatretryOn429Treat 429 as worth another attempt

Pool

keepAliveReuse a connection for more than one requestmaxConnectionsHow many may be open at oncemaxPerHost…and how many to any one hostacquireTimeoutMsHow long a request waits for a free slot

Capture

Nothing has run yet. Configure the client and run it — the capture is what you will be graded on.