Huawei H12-831_V1.0 Exam - Topic 7 Question 71 Discussion

Comprehensive and Detailed In-Depth

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.

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