a) Your small company of less than 200 employees lias been assigned a class C ne

ID: 3689276 • Letter: A

Question

a) Your small company of less than 200 employees lias been assigned a class C network by its ISP. The class C network address assigned to you is 204.45.87.0. You need to divide this into three subnets for the administration group, the accounts team, and the development group. Assume the first and last subnets are usable. i) [List the network addresses for the subnets in dotted-decimal slash notation. ii) What is the broadcast addresses for these subnets? iii) Give the subnet mask. iii) How many hosts are in each subnet? b) Compare message delivery in IP to message delivery at the data-link layer. c) How are a network address and a broadcast address represented in an IP address? d) Packet delivery is unreliable in IP. What four things can happen to packets that make their delivery unreliable? What does IP do when any one of these conditions occur? e) Why are the class A addresses 10.x.y.z, the class B addresses 172.16- 31.y.z, and the class C addresses 192.168.y.z special? Will packets transmitted through the Internet ever have these as source or destination addresses?

Explanation / Answer

Bits of the Network

Subnet Masks allocated

Borrowed Bits

Subnets possible

Number of Hosts per subnet supportable

Assigned for groups

Total Hosts for all subnets

24 to 25

255.255.255.0 to 255.255.255.128

0 and 1

1 and 2

254 + 2*126 = 506

Admin group

506

26 to 27

255.255.255.192 to 255.255.255.224

2 and 3

4 and (7+1)

4*62 + (7+1)*30 = 477 + 11

Accounts group

477+11

28 to 30

255.255.255.240 to 255.255.255.252

4, 5, and 6

16, 32 ans 64

16*14 + 32*6 + 64*2 = 224 + 192 + 127+1 = 544

Development group

544

The total hosts is always approximately around 500 for each of the 3 groups

given that there are only less than 200 employees, we have sufficient address for all the hosts

Class

from IP

to IP

10.0.0.0

10.255.255.255

As the class A ip address 10.x.y.z is reserved for private purpose it is special

172.16.0.0

172.31.255.255

the class B addresses 172.16- 31.y.z are reserved for private purpose it is special

192.168.0.0

192.168.255.255

the class C addresses 192.168.y.z is reserved for private purpose it is special

The packets transmitted through the Internet can never ever have these special and private addresses as source or destination addresses as the data packets with these addresses will be dropped by the router