Arizona College of Allied Health What is the ISO OSI Reference Model Questions
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Lecture 1
What is the ISO OSI Reference Model?What is “OSI”?
How many layers are in the model?What do they represent?
What is the conceptual relationship between layers in two communicating systems?
What is the actual path for data moving in or out of a layer?
How many layers will be used in a switch?A router?A gateway application?A server?
What is TCP/IP? Why is it named “TCP/IP”?
Does the term “network” include the computers attached to networking devices?
Why is it impractical to manage point-to-point connections between devices (except for a trivially small number of them)?
At each layer, the unit of data has a different name.Can you name some (especially at layers 2, 3)?
What data values are used to identify the source and destination at different layers?
What is the client-server model?How does it work?
What is an alternative to client-server?How is it different?
What should be specified in a policy document?
Why is a “perfect” security solution not practical?
What is a security mechanism?What is a pervasive mechanism?What is a specific mechanism?
What is the cardinality (number-to-number) of the relationship between services and mechanisms?
Can you explain why?
What is a threat in this context?Is it certain to occur?
What is an attack in this context?What does it require?
What is the relationship between a threat and an attack?
Lecture 2
What is meant by “security”?Why do we need it?What needs to be “secured”?
What are some types of threat relevant to a data communication system?
Can you give examples of each type?
A threat can be accidental or intentional.What is the difference?
A threat can be active or passive.What is the difference?
What are two types of passive attack?What are four types of active attack?
Can you explain each type?What service is being targeted?
What is required for a man-in-the-middle attack?
Review
the attack diagrams.Can you explain which type/s apply in each case?Can
you define each of the following services in plain English?
- access control
- data confidentiality
- authentication of data integrity
- authentication of data origin
- non-repudiation of origin- availability
Number theory – each number system works the same way.
Why are computers designed to use binary numbers?
What are Boolean operations?
Can you explain in plain English (using “true” and “false”) the NOT, AND, OR, XOR operations?
How does bitwise XOR work?What operation is its inverse?
How does modular arithmetic work?What is the range of values for a particular modulus?
Modular
addition enables modular multiplication which enables modular
exponentiation.Why is modular exponentiation important in cryptography?