🌐TCP

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Also known as: TCP/IP, Transmission Control Protocol

Reliable, ordered, error-checked transport protocol delivering a byte stream over IP networks.

DESCRIPTION

TCP is a connection-oriented transport protocol providing reliable, ordered delivery of bytes between applications. It implements flow control, congestion control, and retransmissions to ensure correctness. A three-way handshake establishes connections, and ports identify endpoints. TCP underpins most web and application traffic, layering above IP and below protocols like TLS and HTTP. Performance tuning often involves window sizes, buffer management, and congestion algorithms.

ALTERNATIVE DEFINITIONS

Wikipedia

The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite. It provides reliable, ordered, and error-checked delivery of a stream of bytes between applications running on hosts communicating via an IP network.

Highlights reliability, order, error checking, and byte-stream delivery.

Source

MDN Web Docs

TCP stands for Transmission Control Protocol, and is one of the main Internet protocols. It guarantees the reliable delivery of data.

Concise developer-focused emphasis on reliability.

Source

Cloudflare

Transmission Control Protocol (TCP) is a transport protocol used by applications that require guaranteed delivery.

Stresses use cases that need guaranteed delivery.

Source

RELATED TERMS

Internet Protocol Congestion Control Flow Control Three-Way Handshake Port Socket TLS Hypertext Transfer Protocol Network Latency

COMPETING TERMS

UDP

KNOWLEDGE AREAS

Infrastructure Data Integration & Interoperability Data Security Real-time & Streaming Data

TARGET AUDIENCE

Software Developer DevOps Engineer Cloud Architect Data Engineer

EXTERNAL SOURCES

• Wikipedia - Transmission Control Protocol
• IETF - TCP standard specification
• MDN Web Docs - Developer glossary entry
• Cloudflare - Network learning resource
• Cisco - TCP/IP overview for practitioners

TOP QUESTIONS

What makes TCP reliable compared to UDP?

TCP implements acknowledgments, retransmissions, sequencing, and flow control. UDP is connectionless and does not guarantee delivery or order.

Category: Comparison

What is the TCP three-way handshake?

A connection setup sequence: SYN, SYN-ACK, ACK. It establishes parameters before data transmission.

Category: Definition

How does TCP handle congestion?

Algorithms like Reno, CUBIC, and BBR adjust sending rates based on network feedback to avoid congestion collapse.

Category: Performance

What is a common mistake configuring TCP?

Ignoring buffer sizes and window scaling for high-latency, high-bandwidth links limits throughput.

Category: Mistakes

How does TLS interact with TCP?

TLS typically runs above TCP, providing encryption, integrity, and authentication for the byte stream.

Category: Management

How do you monitor TCP performance?

Measure RTT, retransmissions, window sizes, and congestion signals. Use tools like netstat, tcpdump, and performance dashboards.

Category: Observability

When should I prefer UDP over TCP?

For low-latency, real-time applications that tolerate loss, such as gaming or streaming, UDP can be preferable.

Category: Opinion

What ports are relevant to TCP?

Ports identify application endpoints, e.g., 80 for HTTP and 443 for HTTPS. Custom services use configurable ports.

Category: Definition

How does TCP impact application throughput?

Congestion control and window sizes influence throughput. Tuning and protocol choice affect performance under varying network conditions.

Category: Performance