CCNA IP Routing Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  PPP

  Why this is correct

  PPP (Point-to-Point Protocol) is a data-link layer WAN encapsulation specifically designed for establishing and maintaining point-to-point connections over serial links. It provides essential features such as authentication (PAP/CHAP), error detection, and optional multilink bundling, making it the standard for legacy serial WAN interfaces. This directly aligns with the question's focus on WAN technologies, confirming PPP as the correct answer.

• ✗

  CAPWAP

  Why it's wrong here

  CAPWAP (Control and Provisioning of Wireless Access Points) is a protocol used for communication between wireless access points and a wireless LAN controller. It operates over UDP and manages the control channel (configuration and management) and data channel (user traffic) in wireless networks, not over serial WAN connections. Since it bears no relationship to WAN encapsulation on serial links, it is not a valid choice here.

  When this WOULD be correct

  If the exam question asked about protocols used for managing wireless networks or controlling access points in a WLAN environment, CAPWAP would be the correct answer, as it specifically addresses the management of multiple access points in a centralized manner.

• ✗

  SNMP

  Why it's wrong here

  SNMP (Simple Network Management Protocol) is an application-layer protocol designed for collecting and organizing management information from network devices, such as routers and switches. It uses UDP ports 161/162 and relies on OIDs (Object Identifiers) to query or set device parameters, but it has no role in encapsulating data for WAN transmission. As a management protocol rather than a WAN encapsulation, SNMP is incorrect for this question.

  When this WOULD be correct

  If the exam question were to ask about the protocol used for network management and monitoring of devices in a WAN environment, SNMP would be the correct answer. For instance, a question could specify the management of network devices and their performance metrics.

• ✗

  STP

  Why it's wrong here

  STP (Spanning Tree Protocol) operates at the data-link layer but serves a completely different purpose: it prevents switching loops in Ethernet LANs by dynamically blocking redundant ports. It is implemented on switches and bridges, not on serial WAN interfaces, and it does not encapsulate or transmit data across a WAN. Therefore, STP is not a WAN encapsulation and is incorrect for this question.

  When this WOULD be correct

  If the exam question asked about protocols used to manage network topology and prevent loops in a switched network, STP would be the correct answer, as it is specifically designed for that purpose.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”