Data Communication & Networks · 2025–26

DCN Practical Exam Kit

Ten selected experiments · aim, procedure, runnable code, illustrated output and result

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Experiment 6 — Ethernet LAN, VLAN and MAC Layer Analysis

Manual pages: 56–67 | Tools: Cisco Packet Tracer + Wireshark

AIM

To configure an Ethernet LAN and VLANs using Cisco Packet Tracer and capture/analyze MAC layer packets using Wireshark.

TOPOLOGY

PC0 Fa0/1 ---PC1 Fa0/2 ---- Switch0 (2960)
PC2 Fa0/3 ---/  VLAN 10: Fa0/1, Fa0/2 (SALES)
PC3 Fa0/4 --/   VLAN 20: Fa0/3, Fa0/4 (HR)

PART A — ETHERNET LAN EXECUTION

  1. Place 1 switch (2960) and 4 PCs, connect each PC using Copper Straight-Through to Fa0/1–Fa0/4.
  2. Initially set PC0–PC3 to 192.168.1.1, .1.2, .1.3, .1.4, mask 255.255.255.0, no gateway.
  3. PC0 Command Prompt: ping 192.168.1.4 → successful replies.

PART B — VLAN EXECUTION

  1. Open Switch0 → CLI; enter Switch0_VLAN.cli. Check port labels before configuring.
  2. Use show vlan brief: VLAN 10 SALES on Fa0/1–2; VLAN 20 HR on Fa0/3–4.
  3. Change PC0→192.168.10.1, PC1→192.168.10.2, PC2→192.168.20.1, PC3→192.168.20.2, mask /24, gateway blank.
  4. PC0 ping 192.168.10.2 → success. PC2 ping 192.168.20.2 → success.
  5. PC0 ping 192.168.20.1 → fail without inter-VLAN routing (can be timeout or unreachable).

PART C — WIRESHARK EXECUTION

  1. Open Wireshark; select own active Ethernet/Wi-Fi interface, start capture.
  2. Generate regular traffic (e.g., ping a reachable device on own network), stop capture.
  3. Filter eth; select Ethernet II and note Source MAC, Destination MAC, EtherType (IPv4 0x0800, ARP 0x0806, IPv6 0x86DD).
  4. Filter arp; note sender/target MAC/IP on requests and replies.
  5. On an authorized trunk capture, 802.1Q VLAN tags may show VLAN ID. A normal PC access port and Packet Tracer network won't automatically expose such tags in your Windows Wireshark.
  6. Save .pcapng.

EXPECTED OUTPUT

10 SALES active Fa0/1, Fa0/2
20 HR    active Fa0/3, Fa0/4
Same VLAN ping: SUCCESS
Different VLAN ping: FAIL without routing
Ethernet II: Source <MAC> Destination <MAC> Type IPv4

RESULT

Thus, Ethernet LAN and VLANs were configured; same-VLAN connectivity succeeded, different-VLAN communication required routing; Wireshark MAC fields were examined.

VIVA