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Network Layout
As briefly mentioned, the network layout in this exercise was more complex compared
to previous simulations and includine: a backbone router network, a traditional switch-
based classroom wired network, a wireless LAN for the apartment buildings and
a dedi-
cated IoT network based also on switch.
The backbone network was created utilizing three interconnected routers. Every router
had a connection to the other two in order to build a redundant infrastructure that could
withstand failures of trunks between the routers.
In order to represent a realistic network where routers were physically located in different
campus building, optical Fast-Ethernet cabling was used instead of traditional straight
copper cables.
Figure 38
– Smart-Campus network topology
For keeping the routing between the backbone devices simple yet, to allow full connec-
tivity between the three networks, a basic Routing Information Protocol (RIP) was used
in the router configuration. RIP is a very simple, and old, routing protocol that periodically
shares routing table between devices. In real life complex scenarios the protocol is usu-
ally not utilized due to its scalability limitation, as protocol in fact allows only a maximum
of fifteen network hops .
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However, due to its setup simplicity, RIP was a perfect candidate for routing protocol in
Cisco Packet Tracer exercise.
In each router the setup was done adding the directly connected networks IPs in the RIP
configuration as shown in the Figure 39, routing table exchange will then take care of
spread the routing
logic between the device, as illustrated in the Figures 40 and 41.
Figure 39 - Example of simple RIP setup of the Classroom router
Figure 40 - Example of RIP messages broadcasting by the Classroom router
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Figure 41 - Packet captured during RIP routing message
broadcasting
Along with the backbone connection each router was also connected to one of the three
sub-networks: class building network, apartment building network and IoT network.
All the three networks were physically separated by placing them in an own dedicated
physical container.
The first network was a simple network for emulate a PC classroom where, two PCs,
one network printer and a server were connected by Ethernet cables to the classroom
switch. Switch was then connected to one of the Ethernet port of the router. DHCP func-
tions were carried on by the local servers.
The apartment building network was also a simple WLAN network that simulated a wire-
less connectivity in the students apartment buildings. In this case a WLAN router was
utilized in order to create the local wireless network, router was then connected with one
of the backbone routers. DHCP functions in this network
were also carried on by the
WLAN router. One laptop and a smartphone were connected to the wireless network.
Last, but most important network, was the IoT network. This was a switch-based network
connected to the third backbone router. IoT devices and IoT server were all connected
to the same switch. In the original specification of the IoT simulation a WLAN router was
supposed to be utilized to connect all the IoT device, making the simulation closer to the
reality. However, due to the coverage range of WLAN signal, and the absence of wireless
repeaters in Cisco Packet Tracer, the furthest IoT devices had very bad coverage and
sometimes connection to the IoT server would timeout and fail.
Usage of switch and
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copper cables was perhaps not fully realistic and not applicable
in real life applications,
but suited better for this Cisco Packet Tracer exercise.
The IoT server, in addition to IoT backend intelligence, was also utilized as DNS server
and DHCP server allocating IP address to the connected IoT devices.
