ITPEC FE Morning October 2022 Question 30
ITPEC FE Morning October 2022 — Question 30 of 80
MAC vs IP addressing in routed networks — identify source/destination addresses at each hop.
When PC01 (192.168.1.31) sends a packet to PC03 (192.168.2.31), the addresses behave differently at each layer:
IP addresses (Layer 3) — end-to-end, never change:
- Source IP: 192.168.1.31 (PC01)
- Destination IP: 192.168.2.31 (PC03)
MAC addresses (Layer 2) — change at every hop:
- On segment Switch1 → Router:
- Source MAC: aa:aa:aa:aa:aa:aa (PC01)
- Destination MAC: cc:cc:cc:cc:cc:cc (Router port 01)
- On segment Router → Switch2:
- Source MAC: dd:dd:dd:dd:dd:dd (Router port 02)
- Destination MAC: ee:ee:ee:ee:ee:ee (PC03)
Why not others:
- (a) Destination IP 192.168.1.11 is the router's port, not PC03
- (c) Destination MAC points to PC03 directly, but the packet hasn't reached that segment yet; destination IP is also wrong
- (d) Destination MAC ee:ee:ee:ee:ee:ee is PC03's MAC — not reachable from Switch1's segment
Key rule: IP = end-to-end (unchanged). MAC = hop-by-hop (points to next device on the path).
AI-generated — may contain errors
The original exam layout is preserved in the image so diagrams, formulas, tables, and code remain accurate.
This question comes from an official ITPEC past paper. ITPEC Practice is an independent study tool and is not affiliated with ITPEC. See the official FE past-paper collection or Report an issue.