Q2: Application Layer


Suppose that:
- You own a lot of beverage vending machines connected to the lnternet.
- You want to manage your vending machines from the operation center using the Internet.
Design a client/server type protocol called SVMP (SimpleVending machine Management Protocol).
- client:PC at operation center
- server: each vending machine

·Assumptions on vending machines
- Each vending machine sells k kinds of beverages (e.g., coffee, tee, cola, etc.), each of which is stored in a separate storage room.
-k is dependent on vending machines.
- Vending machine has machine level attributes (e.g., location, proceeds, etc.) and storage room level attributes (e.g., number of remaining items, current temperature, etc.).
- You want to get attribute information through SVMP.

i. Define attributes:
a.  machine level attributes
b.  storage room level attributes
ii.  Describe design policy considering requirements shown below:
a.  Only privileged client can access vending machines through SVMP.
b. Client is notified of error situations of vending machines through SVMP.

iii.Draw message format(s) of SVMP in figure(s).
- It is assumed that the message is composed of several fields.- Define the name of each field of SVMP message.
- Define the length of each field of SVMP message.
iv. Draw message sequences of the following procedures (in figures):
a.Privileged client gets information of vending machines.b. Client is notified of error situations of vending machines.
- In each figure, describe concrete value of each field if possible.