We have a small office with our own VPN setup. We occasionally experience failures in our internet connection where we cannot access the internet. Most of the time the internet connection will resume by itself(without me doing anything) after a period of time(10 mins).

Would you be able to suggest possible causes of the connection failure so I can then go and run some tests?

Our network architecture is like so:

• A 'Billion' brand router that is connected to the internet via phone cable and then connected to our Cisco Switch
• A Cisco Switch/Bus which is connected to all our office nodes, our external harddrive and also to our router as stated above. All connections are via ethernet cable
• A series of work computers(nodes) connected via ethernet cable to the Cisco switch.
• Our ISP is TPG Australia
• We have a Virtual Private Network
• All the ethernet cables are about 3 years old

Do you think that the causes of our intermittant connection problems could be due to the following:

• Data collisions in the ethernet cables
• Old/Faulty ethernet cables
• Our ISP has bad service
• Can you think of any other causes of the problem?