In local area networking on earlier Microsoft based systems, what are NETBIOS and NETBEUI and how are they related to each other?

Introduction / Context:
NETBIOS and NETBEUI are terms that appear in the history of Microsoft networking and LAN protocols. Although they are less common today, exam questions still test whether you understand their roles. NETBIOS relates to an application programming interface and naming service, while NETBEUI is associated with the transport of NETBIOS messages. This question explores that relationship and asks you to select the correct description.

Given Data / Assumptions:

- The question focuses on earlier LAN environments, especially Microsoft networks.- We are asked to distinguish between NETBIOS and NETBEUI and explain how they fit together.- Only one option describes both components accurately and in the correct roles.

Concept / Approach:
NETBIOS stands for Network Basic Input Output System. It defines an interface and services for applications, including name registration, name resolution, and session services for communication between applications on different hosts. It was originally designed to run on top of small LAN protocols. NETBEUI stands for NETBIOS Extended User Interface. It is a simple, non routable transport protocol that encapsulates NETBIOS messages for transmission on a local area network. Together, NETBIOS provides the application level services, while NETBEUI provides the underlying transport on a single broadcast domain.

Step-by-Step Solution:
Step 1: Identify NETBIOS as an API and service specification. It provides functions for name registration, name resolution, and session oriented communication for applications.Step 2: Identify NETBEUI as a small transport protocol that carries NETBIOS messages over Ethernet or similar LAN technologies.Step 3: Recognise that NETBEUI is non routable, which limits it to small or medium sized LANs and makes it unsuitable for large routed internetworks.Step 4: Option A states that NETBIOS is an API providing session and name services, and NETBEUI is a non routable transport protocol that carries NETBIOS traffic, which matches historical descriptions.Step 5: Option B incorrectly claims that NETBIOS is a hardware connector and NETBEUI a power supply standard, which is nonsense in a networking context.Step 6: Option C incorrectly associates NETBIOS with modern Internet routing and NETBEUI with IPsec encryption, which is not supported by any technical documentation.Step 7: Option D ties both terms to wireless frequency bands, which is unrelated to their actual meaning.Step 8: Option E incorrectly treats NETBIOS and NETBEUI as web browser features and file formats.

Verification / Alternative check:
Historical documentation for Microsoft LAN Manager and early Windows networking explicitly states that NETBIOS is an API and naming protocol, while NETBEUI is a simple transport mechanism. Network configuration tools from that era allowed administrators to choose NETBEUI as a protocol stack to carry NETBIOS traffic. As networks grew, NETBIOS traffic was later carried over routable protocols like IP using NETBIOS over TCP or IP, which further confirms that NETBIOS itself is an API and service layer, not a standalone network protocol bound to one transport.

Why Other Options Are Wrong:
Options B, C, D, and E all describe roles that are completely unrelated to the historical and technical use of NETBIOS and NETBEUI. They associate these names with hardware connectors, power supplies, routing protocols, encryption mechanisms, wireless frequencies, and browser plug ins, none of which is accurate. These distractors are intended to test whether you actually recognise the legacy networking terms or are simply guessing based on sound alone.

Common Pitfalls:
Students often confuse NETBIOS and NETBEUI because the names are similar and both appear in old Windows network configuration screens. A helpful memory aid is to remember that NETBIOS is the higher level interface and naming service, while NETBEUI is just one possible transport for that interface. Also note that NETBEUI is non routable, which made it simple but limited in large networks, leading to its replacement by TCP or IP based solutions.

Final Answer:
NETBIOS and NETBEUI are correctly described as follows: NETBIOS is an API providing name and session services, and NETBEUI is a small non routable transport protocol that carries NETBIOS traffic over a LAN, as in option A.