Subnetting Calculation

There are a total of 9 faculties in UTeM and for every faculty, the number of students are within 500 - 1000. Based on the this situation, the private addressing scheme that are suggested for UTeM network is

Network Number : 128.168.0.0/16

Subnet Mask : 255.255.0.0

which have a block size of 65,536. In order to make the network more efficient and reduce congestion, the network will be divided into smaller networks to provide each faculty with their own network and network address. Concept of subnetting will be incorporated in which bits from the host portion of the IP address will be taken and reserved to define the subnet address. 

The IT Center will be assigned as the 7th available subnet with their own network address. From this network address, Ulearn System Server will be assigned as the 5th available address. 

Since there are a total of 9 faculties, there are at least 9 subnets needed so that each faculty can be assigned with 1 subnet. The number of bits borrowed from host id will be calculated using the formula: 

Nearest to 9 is 16, so a = 16

b = 256 16, so b = 16

        2^n = b, n = bits to borrow in mask

2^n = 16, n = 4

The new subnet mask will be: 

In decimal : 255.255.240.0/20

In binary : 11111111 11111111 11110000 00000000

From the calculation, 4 bits have been borrowed, which results in 20 bits for the network address and 12 bits for the host address. Now we need to find the quantity of host per subnet. 

Largest subnet = 1000 host

Quantity of host = 2H - 2 = 1000

        2^H = 210

        H = 10, 210 - 2 = 1024 - 2 = 1022 >= 1000

Now we will construct the IP address table. We will have a total of 16 subnets, each with 1022 valid hosts. Each subnet will have a subnet address and broadcast address, which results in each subnet having a range of 1024. 

Since there are only 10 host id needed for the host id, the bits borrowed for the subnet can be increased to 6 bits which results in 64 subnets. 

Subnet	Network Address	Usable Host Range	Broadcast Address
0	128.168.0.0	128.168.0.1 - 128.168.3.254	128.168.3.255
1	128.168.4.0	128.168.4.1 - 128.168.7.254	128.168.7.255
2	128.168.8.0	128.168.8.1 - 128.168.11.254	128.168.11.255
3	128.168.12.0	128.168.12.1 - 128.168.15.254	128.168.15.255
4	128.168.16.0	128.168.16.1 - 128.168.19.254	128.168.19.255
5	128.168.20.0	128.168.20.1 - 128.168.23.254	128.168.23.255
6	18.168.24.0	128.168.24.1 - 128.168.27.254	128.168.27.255
7	128.168.28.0	128.168.28.1 - 128.168.31.254	128.168.31.255
8	128.168.32.0	128.168.32.1 - 128.168.35.254	128.168.35.255
9	128.168.36.0	128.168.36.1 - 128.168.39.254	128.168.39.255
10	128.168.40.0	128.168.40.1 - 128.168.43.254	128.168.43.255
11	128.168.44.0	128.168.44.1 - 128.168.47.254	128.168.47.255
12	128.168.48.0	128.168.48.1 - 128.168.51.254	128.168.51.255
13	128.168.52.0	128.168.52.1 - 128.168.55.254	128.168.55.255
14	128.168.56.0	128.168.56.1 - 128.168.59.254	128.168.59.255
15	128.168.60.0	128.168.60.1 - 128.168.63.254	128.168.63.255
16	128.168.64.0	128.168.64.1 - 128.168.67.254	128.168.67.255
17	128.168.68.0	128.168.68.1 - 128.168.71.254	128.168.71.255
18	128.168.72.0	128.168.72.1 - 128.168.75.254	128.168.75.255
19	128.168.76.0	128.168.76.1 - 128.168.79.254	128.168.79.255
20	128.168.80.0	128.168.80.1 - 128.168.83.254	128.168.83.255
21	128.168.84.0	128.168.84.1 - 128.168.87.254	128.168.87.255
22	128.168.88.0	128.168.88.1 -128.168.91.254	128.168.91.255
23	128.168.92.0	128.168.92.1 - 128.168.95.254	128.168.95.255
24	128.168.96.0	128.168.96.1 - 128.168.99.254	128.168.99.255
25	128.168.100.0	128.168.100.1 - 128.168.103.254	128.168.103.255
26	128.168.104.0	128.168.104.1 - 128.168.107.254	128.168.107.255
27	128.168.108.0	128.168.108.1 - 128.168.111.254	128.168.111.255
28	128.168.112.0	128.168.112.1 - 128.168.115.254	128.168.115.255
29	128.168.116.0	128.168.116.1 - 128.168.119.254	128.168.119.255
30	128.168.120.0	128.168.120.1 - 128.168.123.254	128.168.123.255
31	128.168.124.0	128.168.124.1 - 128.168.127.254	128.168.127.255
32	128.168.128.0	128.168.128.1 - 128.168.131.254	128.168.131.255
33	128.168.132.0	128.168.132.1 - 128.168.135.254	128.168.135.255
34	128.168.136.0	128.168.136.1 - 128.168.139.254	128.168.139.255
35	128.168.140.0	128.168.140.1 - 128.168.143.254	128.168.143.255
36	128.168.144.0	128.168.144.1 - 128.168.147.254	128.168.147.255
37	128.168.148.0	128.168.148.1 - 128.168.151.254	128.168.151.255
38	128.168.152.0	128.168.152.1 - 128.168.155.254	128.168.155.255
39	128.168.156.0	128.168.156.1 - 128.168.159.254	128.168.159.255
40	128.168.160.0	128.168.160.1 - 128.168.163.254	128.168.163.255
41	128.168.164.0	128.168.164.1 - 128.168.167.254	128.168.167.255
42	128.168.168.0	128.168.168.1 - 128.168.171.254	128.168.171.255
43	128.168.172.0	128.168.172.1 - 128.168.175.254	128.168.175.255
44	128.168.176.0	128.168.176.1 - 128.168.179.254	128.168.179.255
45	128.168.180.0	128.168.180.1 - 128.168.183.254	128.168.183.255
46	128.168.184.0	128.168.184.1 - 128.168.187.254	128.168.187.255
47	128.168.188.0	128.168.188.1 - 128.168.191.254	128.168.191.255
48	128.168.192.0	128.168.192.1 - 128.168.195.254	128.168.195.255
49	128.168.196.0	128.168.196.1 - 128.168.199.254	128.168.199.255
50	128.168.200.0	128.168.200.1 - 128.168.203.254	128.168.203.255
51	128.168.204.0	128.168.204.1 - 128.168.207.254	128.168.207.255
52	128.168.208.0	128.168.208.1 - 128.168.211.254	128.168.211.255
53	128.168.212.0	128.168.212.1 - 128.168.215.254	128.168.215.255
54	128.168.216.0	128.168.216.1 - 128.168.219.254	128.168.219.255
55	128.168.220.0	128.168.220.1 - 128.168.223.254	128.168.223.255
56	128.168.224.0	128.168.224.1 - 128.168.227.254	128.168.227.255
57	128.168.228.0	128.168.228.1 - 128.168.231.254	128.168.231.255
58	128.168.232.0	128.168.232.1 - 128.168.235.254	128.168.235.255
59	128.168.236.0	128.168.236.1 - 128.168.239.254	128.168.239.255
60	128.168.240.0	128.168.240.1 - 128.168.243.254	128.168.243.255
61	128.168.244.0	128.168.244.1 - 128.168.247.254	128.168.247.255
62	128.168.248.0	128.168.248.1 - 128.168.251.254	128.168.251.255
63	128.168.252.0	128.168.252.1 - 128.168.255.254	128.168.255.255

The 7th available subnet address for IT Center is 128.168.24.0, the 5th available address in this subnet for Ulearn System Server is 128.168.24.5.