IPv4 vs IPv6 Fragmentation

How IPv6 fragmentation differs from IPv4

This is a hard networking question that tests your understanding of how the two dominant internet protocols handle packet size constraints. It's the kind of question interviewers at infrastructure and network-focused firms ask to distinguish candidates who have read the RFCs from those who have only worked with networks at the application layer.

To answer well, you need to understand the architectural choices each protocol makes when a packet exceeds the maximum transmission unit (MTU) of a link, the role of intermediate routers versus end hosts, and the performance and security implications of each approach. The question rewards precision about where responsibility for fragmentation lies and why those design decisions matter in practice.

• Path MTU discovery and its evolution across protocol versions
• Fragment reassembly and attack surface
• Header structure and extension mechanisms
• End-to-end principle and network layering