Question 1: What are the benefits of using a layered model for computer networks?
Question 2: The three network topologies shown below are all valid Ethernet networks.
a) How many collision domains and broadcast domains are there in each topology?
b) Explain which topology is preferred.
Question 3: Explain why 60.61.62.63/26 is not a valid host IP address.
Question 4: In the following network topology, assume static routes are set and the routers are working properly. Explain why PC A can talk to PC C but PC B cannot talk to PC D.
Question 5: USQ has allocated 172.17.0.0/16 to 6 PC laboratories in Wonderland campus. Each laboratory will have a subnet of its own. The number of hosts in each laboratory is as follows:
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Lab 1 Subnet A
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Lab 2 Subnet B
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Lab 3 Subnet C
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Lab 4 Subnet D
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Lab 5 Subnet E
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Lab 6 Subnet F
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Number of Hosts
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2
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47
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532
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6
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39
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125
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The hosts in each laboratory are linked together using switches. The six laboratories are linked together using a router with six Ethernet interfaces as shown below. In the topology, only two hosts in each laboratory are shown. For each subnet, the gateway will use the first host IP address. The two PCs (for example, PC_B1 and PC_B2) in each subnet shown will be using the second available host IP address and the last available host IP address respectively.
a) Taking into account of possible expansion of laboratory facilities in the future, we have to pack the subnets so that they use minimal IP address space. With this in mind, please assign IP addresses to the PCs and router Ethernet interfaces (gateways) using the table below:
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Device
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IP
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Gateway
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Broadcast IP
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Subnet IP
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PC_A1
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PC_A2
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PC_B1
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PC_B2
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PC_C1
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PC_C2
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PC_D1
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PC_D2
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PC_E1
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PC_E2
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PC_F1
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PC_F2
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b) Implement the network using Packet Tracer 6.0.1 subject to the following conditions:
1. Use one Cisco 2811 router with added Ethernet interfaces.
2. Use one Cisco 2960 24 port switch for each laboratory assuming other access switches can be added later on.
3. The router Ethernet interfaces use the first host IP address of the corresponding subnet assigned to the laboratory.
4. The two PCs shown in the topology should have the second available host IP address and the last available address of the subnet assigned.
c) When a TCP/IP packet travels from PC_A1 to PC_F1, we can capture the packets on their way using simulation mode. Use a Packet Tracer screen capture of the packets to explain where inside a packet/frame you can find:
1) Source MAC address and destination MAC address;
2) Source IP address and destination IP address.