In assessing the health of ISP backbones during our monthlong test, we observed several key differentiators among providers. Here are 10 questions that should help bring out the differences for you as you shop for an ISP:

• What is the slowest circuit on the ISP’s backbone, as a carrier’s network is only as slow as this link?

• How many router hops from the backbone to the customer’s connection?

• During what hours does the ISP conduct scheduled maintenance on its backbone?

• What percentage of total time is allocated to scheduled maintenance on the backbone?

• How much advance notice does the ISP provide for scheduled maintenance and for emergency maintenance on the backbone?

• >On the ISP’s backbone, what are the average and maximum values for jitter?

• On the ISP’s backbone, what are the average and maximum values for one-way delay?

• On the ISP’s backbone, what are the average and maximum values for packet loss?

• Can the ISP demonstrate that jitter, one-way delay and loss on its backbone are roughly the same between any city-pairs on its backbone and in either direction?

• Does the ISP’s network management system assess network health using periodic or continuous monitoring?