I should have included that the C7 router is V4 and the firmware for it and the Zylel modem are both up-to-date.

Rob

Like you said, put the modem in bridge, then configure the C7 as a router. Make sure you configure it correctly, correct wan connection type and so on. Confirm it with Centurylink.

In their wisdom, CenturyLink decided that the problem was that the service to our house was too close to the maximum loop distance to stay consistent (we're at 3910 feet, stated max is 4000). The field techs couldn't see the problem because of its intermittency, but eventually, the support office did see it. Their solution (done just 2 days ago) was to run a 2nd pair of wires into the house and put in a modem that could take 2 pairs. The new modem also allowed them to set the VPI/VCI to 8/35, which the original modem wouldn't (apparently, they were hard-wired in the modem, but not to 8/35). They brought in the 2nd pair, plugged into the modem, were able to set the VPI/VCI, put it in bridge, and so far, we've had reliable 25Mbs signal.

That only took CenturyLink 3 weeks to sort out and fix. Here's hoping! Thanks for the feedback.

Rob