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Difficulty: HardConnection-Oriented vs Connectionless Protocols

A network engineer is optimizing a high-frequency sensor telemetry service that transmits small status updates every 50 milliseconds across a lossy wireless WAN link. The application prioritizes ultra-low latency over absolute delivery, as outdated telemetry is immediately rendered obsolete by the next transmission. Diagnostic captures reveal that the legacy implementation experiences severe delay spikes caused by SYN/ACK negotiation, cumulative acknowledgment processing, and retransmission buffer queuing during temporary signal drops. Which transport layer design change should the engineer implement to eliminate these latency spikes while meeting application requirements?

  1. Transition the service from TCP to UDP to eliminate connection setup handshakes and sliding window flow control overhead.Answer
  2. B
    Maintain TCP as the transport protocol but increase the TCP window size to guarantee packet delivery without queuing delay.
  3. C
    Encapsulate telemetry data directly into Data Link Layer frames to enforce connection-oriented delivery using switch MAC table sockets.
  4. D
    Reassign the TCP application traffic to UDP port 123 to force the underlying TCP stack to operate in connectionless mode.

Answer

Transition the service from TCP to UDP to eliminate connection setup handshakes and sliding window flow control overhead.
The requirement calls for minimal latency and tolerance of missing updates in a real-time telemetry application. Switching to a connectionless protocol like UDP eliminates connection establishment overhead, sequence numbers, acknowledgment tracking, and retransmission delays, resolving the latency spikes caused by TCP's Head-of-Line blocking.

Step-by-Step Solution

1
Analyze the application performance requirements.
The application sends small periodic updates every 50ms, prioritizes minimal latency, and tolerates packet loss because outdated telemetry data is superseded by the next update.
Determines whether connection-oriented reliability or connectionless speed is required.
2
Identify the cause of latency spikes in the legacy system.
TCP's connection-oriented mechanisms (three-way handshake, sequence numbers, ACKs, retransmission buffers, and flow control) create Head-of-Line blocking when packets are dropped.
Isolates transport layer protocol overhead as the root bottleneck.
3
Select the appropriate transport protocol.
UDP provides connectionless, stateless datagram transmission with no handshakes, ACKs, or retransmissions, eliminating latency spikes for real-time streams.
UDP aligns directly with loss-tolerant, latency-sensitive application profiles.

Key Concept

Connection-Oriented (TCP) vs. Connectionless (UDP) Protocol Selection
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Topics

Connection-Oriented vs Connectionless Protocols

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