Question:

a) Give two reasons why the building-block approach is favoured to the traditional network design approach.

b) With reference to network monitoring parameters, distinguish between:

i) Logical network statistics
ii) Physical network statistics

c) Two important system performance parameters are: Availability and Reliability.

i) Describe the difference between those two parameters.

ii) Determine the MTTR to the nearest hour of a system with an availability of 99% with an average of 2 failures per year.

iii) Evaluate the MTBF to the nearest hour if the reliability of a system needs to be 99.99% over 30 days.

d) Give three steps that will be taken to reduce network management costs.

e) Using all of 6 physical disks, sketch the possible arrays that you will implement in RAID 0+1 and showing how stripes A, B, C, D, E and F are written to the arrays. Provide the total effective size of each array if each disk has a size of 20 GB.