Quick Answer
The answer is ip address, subnet mask, and description. These three attributes are typically included in a YANG module for interface configuration because the IETF interface model (RFC 8343) defines them as core operational and administrative parameters: the ip address and subnet mask specify the Layer 3 logical addressing, while the description leaf provides a human-readable string to document the interface’s purpose. On the ENCOR 350-401 exam, this topic tests your understanding of how YANG models structure interface data, often appearing in questions about NETCONF/RESTCONF payloads or model-driven programmability. A common trap is confusing optional attributes like mtu or speed with the mandatory ones; remember that ip address and subnet mask are the fundamental addressing pair, and description is the standard administrative label. For a quick memory tip, think “IP, Mask, Desc” — the three pillars of any interface’s YANG identity.
This 350-401 practice question tests your understanding of automation. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which THREE attributes are typically included in a YANG module for interface configuration? (Choose three.)
switchport mode
Why wrong: Switchport mode is in a separate module.
description
Description is a common attribute.
mtu
MTU is a configurable attribute.
ip address
IP address is a standard interface attribute.
mac address
Why wrong: MAC address is typically a state data.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
description
Option B is correct because the 'description' leaf is a standard attribute in YANG models for interface configuration, providing a human-readable text string to document the interface's purpose. It is defined in the IETF interface model (RFC 8343) and is widely supported across Cisco IOS-XE and NX-OS YANG models.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
switchport mode
Why it's wrong here
Switchport mode is in a separate module.
description
Why this is correct
Description is a common attribute.
Related concept
Read the scenario before looking for a memorised answer.
mtu
Why this is correct
MTU is a configurable attribute.
Related concept
Read the scenario before looking for a memorised answer.
ip address
Why this is correct
IP address is a standard interface attribute.
Related concept
Read the scenario before looking for a memorised answer.
mac address
Why it's wrong here
MAC address is typically a state data.
Common exam traps
Cisco often tests the distinction between configurable YANG leaves (like 'description', 'mtu', 'ip address') and operational state leaves (like 'mac address') or platform-specific extensions (like 'switchport mode') to see if candidates understand the standard IETF interface model versus proprietary additions.
Detailed technical explanation
In YANG, interface configuration models like 'ietf-interfaces' define a list of interfaces with leaves such as 'description', 'mtu', and 'ipv4' (which contains 'address'). The 'mtu' leaf sets the maximum transmission unit in bytes, affecting fragmentation and path MTU discovery. The 'ip address' is configured under the 'ipv4' container as a list of addresses with prefix length, enabling static IP assignment. These three are core configurable attributes in both IETF and Cisco native YANG models.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
What to study next
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FAQ
Automation — This question tests Automation — Read the scenario before looking for a memorised answer..
The correct answer is: description — Option B is correct because the 'description' leaf is a standard attribute in YANG models for interface configuration, providing a human-readable text string to document the interface's purpose. It is defined in the IETF interface model (RFC 8343) and is widely supported across Cisco IOS-XE and NX-OS YANG models.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.
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