4.2.7 Packet Tracer - Configure Router-on-a-Stick Inter-VLAN Routing Answers
Topology
Addressing Table
| Device | Interface | IPv4 Address | Subnet Mask | Default Gateway |
|---|---|---|---|---|
| R1 | G0/0.10 | 172.17.10.1 | 255.255.255.0 | N/A |
| G0/0.30 | 172.17.30.1 | 255.255.255.0 | ||
| PC1 | NIC | 172.17.10.10 | 255.255.255.0 | 172.17.10.1 |
| PC3 | NIC | 172.17.30.10 | 255.255.255.0 | 172.17.30.1 |
Objectives
- Part 1: Add VLANs to a Switch
- Part 2: Configure Subinterfaces
- Part 3: Test Connectivity with Inter-VLAN Routing
Scenario
In this activity, you will configure VLANs and inter-VLAN routing. You will then enable trunk interfaces and verify connectivity between VLANs.
Instructions
Part 1: Add VLANs to a Switch
Step 1: Create VLANs on S1.
Create VLAN 10 and VLAN 30 on S1.
S1(config)# vlan 10 S1(config-vlan)# vlan 30
Step 2: Assign VLANs to ports.
a. Configure interfaces F0/6 and F0/11 as access ports and assign VLANs.
- Assign the port connected to PC1 to VLAN 10.
S1(config)# interface fastethernet 0/11 S1(config-if)# switchport mode access S1(config-if)# switchport access vlan 10
- Assign the port connected to PC3 to VLAN 30.
S1(config)# interface fastethernet 0/6 S1(config-if)# switchport mode access S1(config-if)# switchport access vlan 30
b. Issue the show vlan brief command to verify VLAN configuration.
S1# show vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4
Fa0/5, Fa0/7, Fa0/8, Fa0/9
Fa0/10, Fa0/12, Fa0/13, Fa0/14
Fa0/15, Fa0/16, Fa0/17, Fa0/18
Fa0/19, Fa0/20, Fa0/21, Fa0/22
Fa0/23, Fa0/24, Gig0/1, Gig0/2
10 VLAN0010 active Fa0/11
30 VLAN0030 active Fa0/6
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default activeStep 3: Test connectivity between PC1 and PC3.
From PC1, ping PC3.
C:\> ping 172.17.30.10
Were the pings successful? Why did you get this result?
The pings were not successful. The PCs are on different IP networks and require a router or a Layer 3 switch to provide communication between them.
Part 2: Configure Subinterfaces
Step 1: Configure subinterfaces on R1 using the 802.1Q encapsulation.
a. Create the subinterface G0/0.10.
R1(config)# interface gigabitethernet 0/0.10
- Set the encapsulation type to 802.1Q and assign VLAN 10 to the subinterface.
R1(config-subif)# encapsulation dot1Q 10
- Refer to the Addressing Table and assign the correct IP address to the subinterface.
R1(config-subif)# ip address 172.17.10.1 255.255.255.0
b. Repeat for the G0/0.30 subinterface.
R1(config)# interface gigabitethernet 0/0.30 R1(config-subif)# encapsulation dot1Q 30 R1(config-subif)# ip address 172.17.30.1 255.255.255.0
Step 2: Verify Configuration.
a. Use the show ip interface brief command to verify subinterface configuration. Both subinterfaces are down. Subinterfaces are virtual interfaces that are associated with a physical interface. Therefore, in order to enable subinterfaces, you must enable the physical interface that they are associated with.
R1# show ip interface brief Interface IP-Address OK? Method Status Protocol GigabitEthernet0/0 unassigned YES unset administratively down down GigabitEthernet0/0.10 172.17.10.1 YES manual administratively down down GigabitEthernet0/0.30 172.17.30.1 YES manual administratively down down GigabitEthernet0/1 unassigned YES unset administratively down down Vlan1 unassigned YES unset administratively down down
b. Enable the G0/0 interface. Verify that the subinterfaces are now active.
R1(config)# interface gigabitethernet 0/0 R1(config-if)# no shutdown
Part 3: Test Connectivity with Inter-VLAN Routing
Step 1: Ping between PC1 and PC3.
From PC1, ping PC3. The pings should still fail. Explain.
C:\> ping 172.17.30.10
The switch port connected to the router (G0/1) is not yet configured as a trunk, so VLAN 10 and VLAN 30 traffic cannot reach the R1 subinterfaces.
Step 2: Enable trunking.
a. On S1, issue the show vlan command.
S1# show vlan VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4 Fa0/5, Fa0/7, Fa0/8, Fa0/9 Fa0/10, Fa0/12, Fa0/13, Fa0/14 Fa0/15, Fa0/16, Fa0/17, Fa0/18 Fa0/19, Fa0/20, Fa0/21, Fa0/22 Fa0/23, Fa0/24, Gig0/1, Gig0/2 10 VLAN0010 active Fa0/11 30 VLAN0030 active Fa0/6 1002 fddi-default active 1003 token-ring-default active 1004 fddinet-default active 1005 trnet-default active VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2 ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------ 1 enet 100001 1500 - - - - - 0 0 10 enet 100010 1500 - - - - - 0 0 30 enet 100030 1500 - - - - - 0 0 1002 fddi 101002 1500 - - - - - 0 0 1003 tr 101003 1500 - - - - - 0 0 1004 fdnet 101004 1500 - - - ieee - 0 0 1005 trnet 101005 1500 - - - ibm - 0 0 VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2 ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------ Remote SPAN VLANs ------------------------------------------------------------------------------ Primary Secondary Type Ports ------- --------- ----------------- ------------------------------------------
What VLAN is G0/1 assigned to? VLAN 1
b. Because the router was configured with multiple subinterfaces assigned to different VLANs, the switch port connecting to the router must be configured as a trunk. Enable trunking on interface G0/1.
S1(config)# interface gigabitethernet 0/1 S1(config-if)# switchport mode trunk
How can you determine that the interface is a trunk port using the show vlan command?
The interface is no longer listed in the command output.
c. Issue the show interfaces trunk command to verify that the interface is configured as a trunk.
S1# show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gig0/1 on 802.1q trunking 1
Port Vlans allowed on trunk
Gig0/1 1-1005
Port Vlans allowed and active in management domain
Gig0/1 1,10,30
Port Vlans in spanning tree forwarding state and not pruned
Gig0/1 1,10,30Step 3: Test Connectivity
If the configurations are correct, PC1 and PC3 should be able to ping their default gateways and each other.
C:\> ping 172.17.10.1 C:\> ping 172.17.30.10
What addresses do PC1 and PC3 use as their default gateway addresses?
They use the address of the R1 subinterface in their VLAN: PC1 uses 172.17.10.1 (G0/0.10) and PC3 uses 172.17.30.1 (G0/0.30).
Device Configs - Final
ROUTER R1
! ============================================================== !--- 4.2.7 Packet Tracer - Configure Router-on-a-Stick Inter-VLAN Routing !--- ANSWER SCRIPT FOR ROUTER R1 !--- Usage: copy this whole file and paste it into the R1 terminal (start at the R1> prompt). Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless. ! ============================================================== enable configure terminal ! -------------------------------------------------------------- !--- Part 2: Configure Subinterfaces. ! -------------------------------------------------------------- !--- Step 1a. G0/0.10: 802.1Q encapsulation for VLAN 10 and the VLAN 10 gateway address. interface gigabitethernet 0/0.10 encapsulation dot1Q 10 ip address 172.17.10.1 255.255.255.0 exit !--- Step 1b. G0/0.30: 802.1Q encapsulation for VLAN 30 and the VLAN 30 gateway address. interface gigabitethernet 0/0.30 encapsulation dot1Q 30 ip address 172.17.30.1 255.255.255.0 exit !--- Step 2b. Enable the physical interface; the subinterfaces come up with it. interface gigabitethernet 0/0 no shutdown exit end ! -------------------------------------------------------------- !--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.) ! -------------------------------------------------------------- copy running-config startup-config ! ============================================================== !--- Verification: !--- show ip interface brief -> G0/0, G0/0.10 and G0/0.30 up/up !--- show ip route -> connected 172.17.10.0/24 and 172.17.30.0/24 ! ==============================================================
SWITCH S1
! ============================================================== !--- 4.2.7 Packet Tracer - Configure Router-on-a-Stick Inter-VLAN Routing !--- ANSWER SCRIPT FOR SWITCH S1 !--- Usage: copy this whole file and paste it into the S1 terminal (start at the S1> prompt). Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless. ! ============================================================== enable configure terminal ! -------------------------------------------------------------- !--- Part 1: Add VLANs to a Switch. ! -------------------------------------------------------------- !--- Step 1. Create VLAN 10 and VLAN 30. vlan 10 exit vlan 30 exit !--- Step 2a. F0/11 (PC1) to VLAN 10 and F0/6 (PC3) to VLAN 30 as access ports. interface fastethernet 0/11 switchport mode access switchport access vlan 10 exit interface fastethernet 0/6 switchport mode access switchport access vlan 30 exit ! -------------------------------------------------------------- !--- Part 3: Test Connectivity with Inter-VLAN Routing. ! -------------------------------------------------------------- !--- Step 2b. G0/1 to R1 must be a trunk to carry VLAN 10 and VLAN 30 to the subinterfaces. interface gigabitethernet 0/1 switchport mode trunk exit end ! -------------------------------------------------------------- !--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.) ! -------------------------------------------------------------- copy running-config startup-config ! ============================================================== !--- Verification: !--- show vlan brief -> Fa0/11 in VLAN 10, Fa0/6 in VLAN 30 !--- show interfaces trunk -> Gig0/1 on, trunking, VLANs 1,10,30 active !--- From PC1: ping 172.17.10.1 (gateway) and ping 172.17.30.10 (PC3) -> successful ! ==============================================================
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