Understanding the IPv6 Addressing and IS-IS Network
IPv6 Addressing in the Figure:
R1 has the address: 2000:12::1/64
R2 has the address: 2000:12::0/127
The link between them is using a /127 subnet (2000:12::0/127).
Behavior of IPv6 /127 Subnet Mask
In IPv6, a /127 prefix is commonly used on point-to-point links to avoid the issue of subnet-router anycast (::0).
RFC 6164 recommends using /127 instead of /64 for point-to-point links to reduce unnecessary anycast behavior.
2000:12::0 is the network address (first address in the subnet) and is not assigned to an interface.
Analyzing the Two Statements in the Question
Statement 1: "R1 can ping 2000:12::0"❌ (Incorrect)
In IPv6, the first address (::0) in a /127 subnet is typically reserved as a network address and not assigned to any router.
R1 cannot ping 2000:12::0 because it is not assigned to R2 as an active IP.
Correct ping targets would be:
R1 pinging R2’s actual address (2000:12::1 or 2000:12::2 depending on numbering).
Statement 2: "display ipv6 neighbors command can be used to display the MAC address corresponding to 2000:12::0"❌ (Incorrect)
The display ipv6 neighbors command is used to show the MAC address of an active neighbor (i.e., a reachable device).
Since 2000:12::0 is not assigned to a specific router, it will not have a MAC address in the neighbor table.
Final Conclusion:
❌ R1 cannot ping 2000:12::0 because it is the network address in a /127 subnet.❌ The display ipv6 neighbors command cannot show a MAC address for 2000:12::0 because it is not assigned to a router.
Thus, the correct answer is: B. FALSE.
[Reference:, HCIP-Datacom-Advanced Routing & Switching Technology V1.0 – IPv6 Addressing and IS-IS for IPv6, Huawei Official HCIP-Datacom Study Guide – IPv6 Neighbor Discovery and Point-to-Point Links, RFC 6164 – Using 127-Bit IPv6 Prefixes on Inter-Router Links, , , , ]
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