Ip address, subnets and OSI?

1. UCLA has decided to construct a new computer laboratory. As the network administrator you
are required to maximise the IP addresses assigned to the university. Based on discussion with
your teammates you have agreed to create smaller subnets. One of the IP address blocks you
have agreed with your team members is 192.168.16.0 /27. What will be the number of hosts
for each subnet, the IP address for the subnet mask, the host range for the first subnet?

2. In constructing a network architecture there is a need to know which of the following OSI
layers cater for the security principles of confidentiality, authentication, data integrity and
non-repudiation services. Explain how the OSI layers make provision for these security
concepts