I have a 2910 Dual-WAN router. I am finding that download speeds are very slow when both WAN ports are connected. When I disable one or the other WAN port I get good download speeds.

I have WAN1 connected via a Vigor 100 modem connected to a 8Mb ADSL service with Claranet. I have WAN2 connected via a Vigor 100 modem to a 8Mb ADSL service with Zen Internet. Load Balance Mode on both is set to Auto Weight and Active Mode on both is set to Always On.

When both services are enabled I get download speeds of less than 1Mb. When only one is enabled I get download speeds of 4Mb.

What can I do to have a stable download speeds and have both services enabled?

I had more or less the same fault on a 3300v, all I can tell you is even Draytek support can't solve it!

Thank you for the information. Will be looking at a Cisco solution.

try setting the speeds manually on the wans rather than auto and setting the load balance accordinally.