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Ipv6 neighbor table

As explained in Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

An IPv6 neighbor table is a device-maintained database that maps IPv6 neighbor addresses to link-layer addresses and associated resolution state or interface information.

An IPv6 neighbor table is a device-maintained database of Layer 3 IPv6 addresses and their Layer 2 MAC-address mappings. It also records resolution state and the connected interface, allowing a device to prepare Ethernet frames for IPv6 neighbors. section 21.1.2 section 21.4

Read the table with Cisco IOS:

Verifying a neighbor after a ping

After R1 pings 2001:db8::2, show ipv6 neighbors can display both R2’s global unicast address and its link-local address. Both entries can use the same MAC address and GigabitEthernet0/0 interface. If R1 instead shows PC3 as INCMP, it cannot learn PC3’s MAC address and drops packets that require Ethernet encapsulation. section 21.3.1

How Acing the CCNA Exam: Volume 1 Fundamentals and Protocols covers it

How deep it goes
Defines table fields and demonstrates verification, but defers detailed neighbor-state behavior beyond the CCNA scope.
Examples
Uses Cisco neighbor output after a ping and an INCMP entry that explains failed PC1–PC3 forwarding.
What it assumes
Assumes basic IPv6 and Ethernet addressing while teaching the table’s purpose and verification command directly.
What you can do after
Diagnose IPv6 forwarding problems by inspecting neighbor mappings, states, MAC addresses, and interfaces.
How it connects
Connects NDP, Neighbor Solicitation, Neighbor Advertisement, MAC addresses, link-local addresses, and IPv6 static routes.
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Related concepts

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