A newly provisioned VDSL service using a Draytek 2762 router is unstable, resetting every 20 min or so (15 min minimum, about 1 hr max), 24 hours a day.

Swapped the router out for a Huawei HG-630B overnight and this sync'd up much more quickly, and didn't drop at all overnight.

There is no filter or splitter, but the line is dedicated to the router. There are no analog phones or faxes. There is an alarm but this is internet based and the alarm people promise that the only connection is the LAN, nothing on the phone line.

Speed reported by the router is very good 116M/29M - haven't done a speed test but it feels very snappy when connected.

The Draytek reports a Running Mode: 17A .. is it possible that the Huawei is connecting in a different and more stable mode?

Any thoughts appreciated, as I suspect this is more likely a configuration issue than a faulty router.