Test results show that using the same Internet Service Provider (ISP) for all your business locations improves ping times and performance in applications such as remote desktop between the offices. Recommendation: Use the same ISP for all your business locations!
Note that all this assumes that you are doing more than just surfing the Internet and downloading email at the office. This assumes that your are running a practice management system, or an accounting system, or a customer relationship management system, or doing file sharing between the offices.
So here are the results of tests run between Peachtree City (PTC) GA and Newnan GA, about 14 miles distant.
I did the “latency” tests using a simple program called ping. This sends a small packet of information from PTC to Newnan and back and measures the time the trip takes. This is a measure of “responsiveness” when using a lightly loaded connection (like you have when using remote desktop to access a server in Newnan from PTC.)
Same Internet Service Provider:
PTC office (AT&T) to Newnan office (AT&T) – average ping time is 23/1000ths of a second
PTC Comcast connection borrowed from an office down the street) to Newnan office (AT&T) – what we’ll have after the Comcast install: ave ping time is 30/1000ths of a second
Introducing the “faster” Comcast connection in one office results in ping times between the offices that are 30% slower. This is because the traffic does not stay on the AT&T network but has to travel the additional “hops” between networks.
Note that if both offices could switch to Comcast, we expect the ping times would speed up. (And we’d have the faster “throughput” / big file transfer rates of the Comcast service.)