The Cost of a Trip
A round trip time is how long a message takes to reach the other side and for the reply to come back. It is the unit that governs any request and answer pattern on a network.
Why It Multiplies
Many protocols need several exchanges before useful data flows.
- Opening a connection can take one round trip for the handshake.
- A secure setup can add one or two more round trips.
- Each dependent request waits a full round trip for its answer.
If a task needs ten serial round trips and each trip is one hundred milliseconds, the user waits a full second before bandwidth even matters.
Cutting the Trips
The best speedup is fewer trips, not a wider pipe. Batching requests, reusing connections, and moving servers closer all shrink the count or the length of each round trip.
Key idea
Round trip time is the travel time for a request and its reply, and because many setups need several serial trips, reducing the number of round trips is the strongest lever on perceived speed.