The GATE Grind

GATE 2025 CS (CS1) – Question 40

Computer Networks · Routing: Distance Vector and Link State Routing · 2 marks · Multiple choice

A packet with the destination IP address 145.36.109.70 arrives at a router whose routing table is shown. Which interface will the packet be forwarded to?

Subnet Address | Subnet Mask | Interface
145.36.0.0 | /16 | E1
145.36.128.0 | /17 | E2
145.36.64.0 | /18 | E3
145.36.255.0 | /24 | E4
Default | -- | E5

  1. E3
  2. E1
  3. E2
  4. E5

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: (A) E3

Explanation

The third octet 109 = 01101101. It matches 145.36.0.0/16 and 145.36.64.0/18 (range 64-127), but not the /17 (128-255) or /24. Longest prefix match selects /18, which is E3.