Verification & Packet Tracer Assembly Guide: PTL-0010

Lab ID: PTL-0010
Lab Title: Router-on-a-Stick Inter-VLAN Routing
Category: routing
Difficulty: Intermediate

1. Physical & Packet Tracer Assembly Manifest#

Device Hardware & Module Schedule#

Port-to-Port Cabling Matrix#

Addressing Table#

2. Pre-Configuration & Starter State#

In the starter state (starter):

• Switch S1 has VLAN 10 and VLAN 20 configured on access ports Fa0/1 and Fa0/11.
• Router R1 is unconfigured and physical link Gi0/0/0 is shut down.
• Prior to configuring ROAS, PC-Faculty and PC-Student cannot communicate (isolated by VLAN segmentation).
• Student must configure 802.1Q trunking on Switch S1 Gi0/1, enable Gi0/0/0 without an IP address, configure subinterfaces Gi0/0/0.10 and Gi0/0/0.20 with encapsulation dot1Q and gateway IPs, and verify routed inter-VLAN reachability.

Complete reference configurations:

• configs/R1.txt
• configs/S1.txt

3. Positive Verification Tests#

Test POS-01: Router Subinterface Operational Status#

• Action: At R1#, issue show ip interface brief.
• Expected Terminal Output:

  R1# show ip interface brief
  Interface              IP-Address      OK? Method Status                Protocol
  GigabitEthernet0/0/0   unassigned      YES unset  up                    up      
  GigabitEthernet0/0/0.10 192.168.10.1    YES manual up                    up      
  GigabitEthernet0/0/0.20 192.168.20.1    YES manual up                    up      
  

• Criterion: Physical parent interface is unassigned and up/up; both subinterfaces are up/up with correct gateway IPs.

Test POS-02: Switch Trunk Status#

• Action: At S1#, issue show interfaces trunk.
• Expected Terminal Output:

  S1# show interfaces trunk
  Port        Mode             Encapsulation  Status        Native vlan
  Gig0/1      on               802.1q         trunking      1
  

• Criterion: Switch port Gig0/1 is actively trunking using 802.1Q encapsulation.

Test POS-03: Inter-VLAN Routing Reachability#

• Action: From PC-Faculty (192.168.10.10), ping PC-Student (192.168.20.10).
• Expected Terminal Output:

  C:\> ping 192.168.20.10
  Reply from 192.168.20.10: bytes=32 time<1ms TTL=127
  Reply from 192.168.20.10: bytes=32 time<1ms TTL=127
  Reply from 192.168.20.10: bytes=32 time<1ms TTL=127
  Reply from 192.168.20.10: bytes=32 time<1ms TTL=127
  

• Criterion: 100% packet success across the router. TTL is 127 (one hop through R1).

4. Negative Verification Tests#

Test NEG-01: Encapsulation VLAN Tag Mismatch#

• Action: On R1, change subinterface encapsulation: interface Gi0/0/0.10 -> encapsulation dot1Q 30. Attempt ping from PC-Faculty to 192.168.10.1.
• Expected Output:

  C:\> ping 192.168.10.1
  Request timed out.
  

• Criterion: R1 drops frames tagged with VLAN 10 because Gi0/0/0.10 is expecting VLAN 30 tags.

Test NEG-02: Switch Trunk Port Reverted to Access Mode#

• Action: On S1, change Gi0/1 to switchport mode access.
• Expected Output:
  • show interfaces trunk on S1 returns no active trunks.
  • Inter-VLAN routing fails completely because the switch strips VLAN tags or blocks multi-VLAN traffic across an access port.

5. Diagnostic & Troubleshooting Reference#