What is the minimum supported MTU for IPv6?

What is the minimum supported MTU for IPv6?

• A. 1200 bytes
• B. 1400 bytes
• C. 1280 bytes
• D. 1500 bytes

Answer: (C)

IPv6 requires that every link can carry a packet of at least 1280 bytes. This baseline ensures a path can deliver IPv6 packets without relying on router fragmentation. Since the IPv6 header is 40 bytes, a 1280-byte MTU leaves room for 1240 bytes of payload, which is sufficient for typical traffic while still guaranteeing reachability across diverse networks. Even though many links use 1500-byte MTUs, that’s not the minimum mandated by the standard; 1280 bytes is the required minimum. The other values don’t meet this network-wide baseline.

IPv6 requires that every link can carry a packet of at least 1280 bytes. This baseline ensures a path can deliver IPv6 packets without relying on router fragmentation. Since the IPv6 header is 40 bytes, a 1280-byte MTU leaves room for 1240 bytes of payload, which is sufficient for typical traffic while still guaranteeing reachability across diverse networks. Even though many links use 1500-byte MTUs, that’s not the minimum mandated by the standard; 1280 bytes is the required minimum. The other values don’t meet this network-wide baseline.