GATE CSE 2024 Session 2 Q32: IPv4 header fields every router modifies

Which of the following fields of an IP header is/are always modified by any router before it forwards the IP packet?

Try it: multiple select: one or more correct options

Select all correct options. No negative marking, no partial marks.

Show answer and explanation

Answer: C, D (official GATE 2024 final answer key)

Concept used: Routers decrement TTL, and any header change forces the header checksum to be recomputed.

First step: Ask which field a router must change at every hop, and what depends on the header's contents.

Full step-by-step solution

Detailed working, common mistakes and linked mock tests will be available with a free GATEiit account. Log-in is coming soon.

Share this question

Source: official GATE 2024 Session 2 CS question paper and final answer key, organised by IISc Bangalore. Question paper · Answer key