Airport Extreme needs ethernet to laptop?

Ive been using a new cable modem and Im having intermittent problems connecting to the internet and getting server not connection requiring me to call the Cable company and unplug in the modem and then it works. I have done this several times in one week, then had a service call from cable company who stated he could not find any problem but the cable modem was a white motorola model ( not sure which) that is known to have problems, so I allowed him to sell me a new one.

When I check my wifi using disk utility there is usually a delay from base station, which has a green light, to internet which is delayed before it turns green.
IS that normal? No I also need to use the ethernet cable from my Macbook Pro, which I was not doing, to my airport extreme. ( Latest tower model). How can I assess if its a cable company issue?