Question 1 – Address usage
Consider the following classless address in a given block:
Calculate the following:
a)the network address,
b)the direct broadcast address, and
c)the range of addresses available for hosts
Show the steps you took to arrive at your answers.
Question 2– Allocating subnets from a block
A company has been granted a block of addresses which includes the address 128.32.16.8/22. Answer the following questions, showing your calculations.
a)Calculate the network address of this block, and total addresses the block contains including special addresses this block can provide.
b)Create the following 4 subnets for this company by calculating the subnet address for each subnet. Answer this question by filling in the table in the Answer template. Your subnets must use contiguous address blocks, i.e., do not leave unallocated addresses in between two consecutive subnets. Use CIDR format for the mask.
I.1 subnet with 128 addresses
II.1 subnet with 64 addresses
III.2 subnets with 32 addresses each
c)After allocating the subnets, how many addresses are unallocated (leftover)? Show your calculations.
Question 3 – Network Tools (Windows)
This part of the assignment requires you to explore some common networking tools, and answer the given questions. netstat and tracert are included in Windows, while Wireshark is free to download and install. Explore these tools, then answer the questions.
a)A Wireshark scan has produced a packet capture, saved to a file named COIT20261_Assign1.pcap and available on the Unit website. Download the file and open it in Wireshark, then answer these questions about the scan:
i.View Frame 98, and answer the following questions: What kind of message is the frame carrying (protocol name/type). What is the destination host’s domain name?
ii.View Frame 644, and answer the following questions: Which transport layer protocol was used? Scan a few more frames down: what general activity was the user most likely engaged in? – give reasons
b)A ‘NETSTAT –aon’ command has given the output as shown below. Focussing on line 2 and 8 (highlighted), determine and write down the name or type of the application that is running over these two connections. What are the major differences between these two TCP connections or applications?
Answer:
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Question Number
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Mark
allocated
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Mark earned
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Question 1: (3 marks)
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3
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a)
b)
c)
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Network address for the IP address 156.120.32.3/26
156.120.32.0/26
Direct Broadcast address
156.120.32.63
Range of address available for hosts
156.120.32.1 - 156.120.32.62
Calculation:
The following table is used for the calculation of number of bits used for subnetting.
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Subnet
Mask
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0
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128
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192
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224
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240
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248
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252
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254
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255
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No. of bits used for subnetting (n)
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0
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1
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2
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3
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4
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5
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6
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7
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8
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Subnet
IP address = 156.120.32.3
Subnet mask = 255.255.255.192
Total bits = 8
Number of bits used for subnetting = 2
Therefore number of bits left for host = 8 – 2
= 6
Value of last bit used for subnet masking = 2^6
= 64
Number of host per subnet = 64 -2
= 62
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1 mark each item, total 3
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Question 2: (8 marks)
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8
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a)
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Block of address granted to the company is 128.32.16.8/22
Network address for this block is 128.32.16.0/22, and the total addresses the block contains including special addresses is 1024.
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1
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b)
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Subnet
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No. addresses
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Subnet address
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Mask /n
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1
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128
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128.32.16.0
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/24
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2
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64
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128.32.17.0
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/25
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3
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32
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128.32.17.128
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/26
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4
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32
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128.32.17.192
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/26
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Calculations:
IP address = 128.32.16.8/22
Binary Representation = 10000000.00100000.000100 00.00001000
Subnet mask = 255.255.252.0
Binary Representation = 11111111.11111111.111111 00.00000000
Network: 128.32.16.0/22 10000000.00100000.000100 00.00000000 (Class B)
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6
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c)
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After the allocation of the subnet 518 number of addresses are left unallocated.
Total number of IP address available for the Subnet = 1022
Allocated IP address for subnet 1 = 254
Allocated IP address for subnet 1 = 126
Allocated IP address for subnet 1 = 62
Allocated IP address for subnet 1 = 62
Therefore, total number of IP address allocated = 254 +126 + 62 + 62
= 504
Hence, The remaining IP address for the subnet = 1022 -504
= 518
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1
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Question 3: (4 marks)
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4
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a)
i)
ii)
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The frame is carrying (UDP/IPv4) message. The destination host domain name is sns.dns.icann.org.
TCP protocol is used for the in the frame 644.
From the analysis of the few more frames down the general activity of the user is analysed and it is found that different protocols are used for accessing the destination address. In the frame 644 a HTTP request is sent to the server for establishment of TCP connection and in the frame 647 another HTTP request is sent for establishing UDP connection.
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1 mark each item, total 2 for 3a.
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b)
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The line 2 and 8 is analysed for determining the application running over the two connection and it is found that the application uses TCP protocol for transmitting data in the network. For the 2nd 8479 port is used for sending the data packet and it reaches the destination server using the port 443 i.e. it uses secure HTTPS protocol over TLS/SSL. For the 8th line port 80 is used for www (world wide web).
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1
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c)
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The TRACERT command is used for analysing the path used by the source host to reach the destination address. The command prompt is used for performing the TRACEROUTE to reach the website www.bom.gov.au and it is found that 8 hops are needed to be passed for reaching the destination address. Here the IP address of the gateway device through the packet is sent to the destination server is 10.10.30.1 and the destination IP address is 23.58.66.44.
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1
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Total marks awarded
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15 (max)
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Less late penalties
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Less plagiarism penalties
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Total marks earned
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Markers comments:
References
Lammle, T. (2016). CCNA Routing and Switching Complete Deluxe Study Guide: Exam 100-105, Exam 200-105, Exam 200-125. John Wiley & Sons.
Loo, J., Mauri, J. L., & Ortiz, J. H. (Eds.). (2016). Mobile ad hoc networks: current status and future trends. CRC Press.
Medhi, D., & Ramasamy, K. (2017). Network routing: algorithms, protocols, and architectures. Morgan Kaufmann.
Sgambelluri, A., Giorgetti, A., Cugini, F., Bruno, G., Lazzeri, F., & Castoldi, P. (2015, March). First demonstration of SDN-based segment routing in multi-layer networks. In Optical Fiber Communications Conference and Exhibition (OFC), 2015 (pp. 1-3). IEEE.
