I need help creating a context diagram using the below casual format use cases. Please help me identify at least 3 external entities and their inputs and outputs. I have visio and can put together the diagram.

Use Case Name: Ordering an aircraft part from a warehouse

ID: UC-1

Priority: High

Actor: Customer

Description: The customer requests a specific part using the national stock number (NSN). Once the request is put into the system the system identifies the location of the part, reserves it, and sends the invoice to warehouse personnel.

Trigger: Customer needs a part that we stock

Type: External Temporal

Preconditions:

1.The customer logs into their account in order to verify their billing and shipping information.

2.The customer must have the specific aircraft that the parts are associated with.

3.The part ordered must be in stock

Normal Course: Information for Steps:

1.The customer submits an order for the part through our system.

2.The system determines the inventory of the product and their locations.

3.The system identifies the warehouse with stock closest to the customer.

4.The system authenticates the customers billing and shipping information.

5.The system reserves the part and sends an invoice to the warehouse.

Postconditions:

1.The warehouse personnel pull and ship the part.

2.Customer orders are stored in a central database.

3.The inventory level is updated to reflect the change.

Exceptions:

E1. The part is discontinued

1.The system informs the customer of this information.

2.The system provides suitable substitutes for the part.

3a.The customer accepts the alternative part.

4a.The system starts a new normal course.

3b.The customer declines the part.

4b.The system terminates the use case.

Use Case Name: Update system serversID: UC2Priority: High

Actor: Server

Description: Sales representatives need to have the most current inventory information. With that being said, the system must upload updated inventory information to the servers every 30 seconds.

Trigger: Servers require update

Type: External Temporal

Preconditions:

1.The system has a running 30 second internal clock.

2.The system must be connected to the server.

Normal Course: Information for Steps:

1.The system detects the end of the 30 second period

2.The system compiles all changes during the period.

3.The system uploads all changes to the server.

4.The system automatically starts a new cycle period.

Postconditions:

1.Current inventory information is present on the servers for use by sakes representatives.

2.A log of the update is archived.

3.The last 100 updates are stored in order to preserve backup files

Exceptions:

E1. The server does not accept the update

1.The system notifies the IT department

2.The IT department runs a network connectivity test.

3a.The system reconnects to the server.

4a.The system starts a new normal course.

3b.The system does not connect to the server.

4b.The system terminates the use case.