Packet Tracer Lab simulation for VLAN, Trunking and Router on a stick.

1. Rafat Khandaker
CCNA PACKET TRACER
ROUTER ON A STICK + VLAN TRUNKING
04/27/2016
Objective:
In this simulation, an example of Vlan trunking was simulated with 2 switches and a router.
The goal of this simulation was to replicate a situation where VLANS are needed to be
configured with the proper trunking and subinterface protocols. I aim to configure the
switches and routers with the correct ios commands to establish: routing on stick and Vlan
trunking. In reality, I expect more complex diagrams to work with but for simplicity sake
and geting the "gist," of the idea; this is a suitable lab to grasp the concept.
THIS IS THE FINISHED DIAGRAM
VLAN THEORY:
In large networks, the network engineer has to mitigate the possibility of broadcast
storms due to large broadcast domains. In a large broadcast domain, it is possible to over-
load the bandwidth because of multiple switches communicating at once. Other problems
due to large broadcast domains are network analyzers which can detect traffic from

2. multiple stations at once, which can be a security issue as well. To solve these problems,
VLANS is a protocol established to separate network broadcast traffic. VLANS are usually
also configured with a router because routers are designed to separate broadcast traffic. In
order to pass this communications between routers and switches, the "Router on a stick"
configuration is used to communicate VLAN traffic between routers and switches.
THE PLAN:
TRUNKING:
Trunking is the link between switches to switches and switches to router, where the VLAN
information can be transmitted. This is important because switches need to agree on which
vlan packets are being transmitted and recieved from switch to switch. Without this
configuration, VLAN information cannot be transmitted and switches will not understand
how to filter traffic based VLAN configuration.
The ports between switches and switch to router need to be configured with Trunk:
switch0 fa(0/1) | switch1 fa(0/1) | switch1 (1/1)
command: #(config-t) switchport mode trunk
Each fast ethernet interface with different vlan configuration needs to be configured
with different ip address
switch0 ( VLAN 1 = 192.168.1.253
VLAN 10 = 192.168.10.253
VLAN 20 = 192.168.20.253 )
switch 1 ( VLAN 1 = 192.168.1.254
VLAN 10= 192.168.10.254
VLAN 20=192.168.20.254 )
ROUTER ON A STICK:
Router on a stick is a sub interface configuration, where one port can be "virtually," split
into multiple ports along with different ip addresses, configured with different subnets. On
a router, broadcast domains are separated by subnetworks; so Vlans are usually assigned
to a different subnetwork.
Router 0 Subinterf ( Fa0/0 = 192.168.1.1
Fa0/0.1=192.168.10.1
Fa0/0.2=192.168.20.1)

3. each host belongs to the same subnetwork of their respected VLAN membership, default
gateway.
PC0 (VLAN 10) IP: 192.168.10.3
PC1 (VLAN 20) IP: 192.168.20.3
PC2 (VLAN 10) IP: 192.168.10.2
PC3 (VLAN 20) IP: 192.168.20.2
Lab0 (Native) IP: 192.168.1.2
Lab1 (Native) IP: 192.168.1.3
IOS CONFIGURATION
SWITCH 0

4. SWITCH 1

6. ROUTER 0

8. PINGS FROM PC 0

10. In here, we can see that all pings were unsuccessful except for the host connected in the
same vlan 10 as pc0, which was pc 2. This is because routing on the router has not been
configured. In order for hosts to communicate with hosts on a separate VLAN, a router is
needed to be configured to route traffic between hosts. We can also see, using the arp -a
command, the arp table shows only hosts with layer 2 address; which can only be
communicated through switch and ports configured with the same VLAN. I also tested the
ping to default gateway to ensure the subinterface on fa0/0.1.
Pings from Lab1

11. Pings from PC 1

12. CONCLUSION
I have successfully created, configured and tested this network for VLAN
configuration. I have successfully configured trunk links with proper configuration
between switch to switch. I have successfully configured sub interface links between
routers and switches to communicate VLAN information.