End Systems and TCP Explained | Generated by AI
Question: What does the term “end system” mean in the context of the provided network protocol question, and can you provide a detailed explanation of the question and answer?
Answer:
Understanding “End System”
In computer networking, an End System (also commonly referred to as a Host) is a device that sits at the edge of the network. It is the source or destination of data communication.
- Examples: Personal computers, servers, smartphones, tablets, and IoT devices.
- Function: End systems run application programs (such as web browsers, email clients, or server software) that generate and consume data.
- Contrast: This is distinct from Intermediate Systems (like routers and switches), which are responsible for forwarding data packets through the network but do not typically originate or terminate the user data themselves.
When a question refers to an “end-system-to-end-system” protocol, it is usually looking for a protocol that manages communication directly between the source host and the destination host, often ensuring reliability or data integrity across the entire path, regardless of the intermediate routers.
Analysis of the Question and Options
The question asks: “Which of the following belongs to the protocol between end systems?”
A. TCP (Transmission Control Protocol) - [Correct]
- Layer: Transport Layer.
- Function: TCP provides reliable, ordered, and error-checked delivery of a stream of bytes between applications running on hosts communicating over an IP network.
- Why it fits: TCP is the classic example of an end-to-end protocol. It establishes a connection (handshake) between the two end systems and maintains state information to ensure data arrives correctly. It hides the complexity of the network (routers, packet loss) from the application running on the end system.
B. IP (Internet Protocol)
- Layer: Network Layer.
- Function: IP is responsible for addressing and routing packets across network boundaries.
- Why it is not the best answer: While IP addresses identify end systems, IP itself is often considered a “best-effort” delivery service. Routing decisions happen at every intermediate router (hop-by-hop). While it connects end systems, TCP is more specifically defined by its end-to-end reliability management between the systems.
C. ARP (Address Resolution Protocol)
- Layer: Link Layer (mostly).
- Function: ARP resolves an IP address to a physical MAC address.
- Why it is incorrect: ARP operates only within a local network segment (broadcast domain). It is not used for communication across the entire internet between distant end systems.
D. PPP (Point-to-Point Protocol) - [Your Answer]
- Layer: Data Link Layer.
- Function: PPP is used to establish a direct connection between two nodes. It is commonly used for dial-up connections or serial links.
- Why it is incorrect: PPP connects two directly connected nodes (often a user to an ISP), but it is not the overarching protocol that manages communication between end systems across a complex network like the Internet. It is a link-layer protocol, whereas the question implies a higher-level communication protocol between hosts.
Conclusion
TCP is the correct answer because it is designed specifically to manage the communication session, reliability, and flow control between two end systems (hosts), ensuring that data sent by an application on one end system is correctly received by the application on the other end system.
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