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mediummultiple choiceObjective-mapped

Which IPv6 protocol function replaces ARP?

Answer choices

Why each option matters

Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.

A

Distractor review

DHCPv6

DHCPv6 provides addressing information, not local-link address resolution by itself.

B

Best answer

Neighbor Discovery

Correct. Neighbor Discovery replaces ARP in IPv6 networks.

C

Distractor review

EUI-64

EUI-64 is one method of generating an interface identifier, not an address resolution protocol.

D

Distractor review

SLAAC

SLAAC is an addressing method, not the ARP replacement mechanism.

Common exam trap

Common exam trap: answer the scenario, not the keyword

A frequent exam trap is selecting DHCPv6 or SLAAC as the protocol replacing ARP in IPv6. DHCPv6 is often confused with address resolution because it assigns IPv6 addresses, but it does not resolve Layer 3 addresses to MAC addresses. SLAAC is another tempting choice since it configures IPv6 addresses automatically, but it also does not perform address resolution. The correct answer is Neighbor Discovery, which uniquely handles address resolution and other local-link functions in IPv6. Misunderstanding these roles can lead to incorrect answers on the CCNA exam.

Technical deep dive

How to think about this question

Neighbor Discovery Protocol (NDP) is a fundamental IPv6 protocol that replaces ARP by resolving IPv6 addresses to MAC addresses on a local network segment. NDP uses ICMPv6 messages to perform address resolution, router discovery, prefix discovery, and duplicate address detection. This protocol is integral to IPv6 because it consolidates multiple functions that were handled by separate protocols in IPv4, streamlining network operations. In Cisco and CCNA contexts, NDP operates by sending Neighbor Solicitation messages to determine the link-layer address of a target IPv6 address. When a device receives this solicitation, it replies with a Neighbor Advertisement containing its MAC address. This process ensures efficient Layer 3 to Layer 2 mapping. Additionally, NDP supports Stateless Address Autoconfiguration (SLAAC) by advertising network prefixes and default routers, which DHCPv6 does not replace. A common exam trap is confusing DHCPv6 or SLAAC with the ARP replacement function. While DHCPv6 provides IP address assignment and SLAAC enables automatic address configuration, neither performs address resolution. Understanding that NDP uniquely handles address resolution and local-link discovery in IPv6 networks is critical to avoid this mistake. Practically, Cisco devices rely on NDP for neighbor reachability and efficient packet forwarding on IPv6 networks.

KKey Concepts to Remember

  • Neighbor Discovery Protocol (NDP) replaces ARP by resolving IPv6 addresses to MAC addresses using ICMPv6 messages.
  • NDP performs multiple functions including address resolution, router discovery, prefix discovery, and duplicate address detection in IPv6 networks.
  • DHCPv6 provides IPv6 address assignment but does not perform Layer 3 to Layer 2 address resolution like NDP.
  • SLAAC enables automatic IPv6 address configuration but does not replace ARP or perform address resolution.
  • Cisco devices use NDP to maintain neighbor reachability and efficiently forward IPv6 packets on local networks.
  • NDP uses Neighbor Solicitation and Neighbor Advertisement messages to map IPv6 addresses to MAC addresses.
  • Confusing DHCPv6 or SLAAC with NDP is a common exam trap that leads to incorrect answers about IPv6 address resolution.
  • Understanding NDP’s role in IPv6 is essential for CCNA exam success and practical IPv6 network management.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Related practice questions

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More questions from this exam

Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.

Question 1

A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?

Question 2

A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?

Question 3

What is the OSPF metric called?

Question 4

A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?

Question 5

A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?

Question 6

A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?

FAQ

Questions learners often ask

What does this 200-301 question test?

Neighbor Discovery Protocol (NDP) replaces ARP by resolving IPv6 addresses to MAC addresses using ICMPv6 messages.

What is the correct answer to this question?

The correct answer is: Neighbor Discovery — IPv6 uses Neighbor Discovery Protocol to resolve Layer 3-to-Layer 2 information and perform related local-link functions such as router discovery and address resolution.

What should I do if I get this 200-301 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.

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