We have noticed disturbing behavior with the Netopia R7100c router on our SDSL 784k link from DSL.net:
When downloading a large file from a high performance internet site (netopia utilization > 97%, for example downloading corel linux through cnet[corellinux-oc_1.1.iso.gz from ftpx.download.com, which was selected from all download sites after canceling the default download from Finland]), all other users have no internet connection (we tested a second different request on the same pc, and with other pcs on different subnets). The netopia does not forward the connection to the backup connection. Pinging to the immediate other side of the dsl link yields typical response time of 20 seconds to 1 minute, with occasional times exceeding 3 minutes.
This problem could kill VPNs as well as create many irate users.
Initially we had the prioritize delay-sensitive data option set to yes. Setting it to no and retesting produced the same results.
Our view expressed to Netopia was the prioritize delay-