Use One of Dual ISP's

In a small office I have Comcast Cable and have recently purchased AT&T DSL. Both ISP's will be active. I want SmartFTP on one PC to use AT&T, the other PC's to use Comcast, and all PC's to see each other on the network.

Why do this? When SmartFTP is uploading large files via Comcast Cable, latency becomes a problem. Pinging the Comcast dsn server shows response time increasing from 4ms to 350ms. Plus Comcast is unreliable with outages now and then. When this occurs I intend to use the AT&T dls to provide an ISP for all PC's. Since the AT&T dsl will be mostly for backup I want to use it for SmartFTP uploads and avoid affecting Comcast response times.

Now the question is how to configure the network to accomplish what I want. I've bogged down with too many possibilities. Any advice is greatly appreciated.


Office has 5 PC's all running Windows XP Pro in a peer-to-peer network, joined with a Gigabit switch and connected to Comcast via a router and cable modem.

The PC running SmartFTP has two NIC's. NIC-A is currently cabled to the switch that is on the office network and Comcast. NIC-B is not yet connected. This PC is used like a file server on the office peer-to-peer network, runs nightly 5GB backups that are uploaded via SmartFTP, and is accessed via the Internet using XP Remote Desktop Connection (RDC).


1) Connect NIC-B to the dsl modem and set up a PPOE dialup in Internet Connections, configured to always dial a connection. Perhaps SmartFTP will use this connection?

Since we have spare equipment, NIC-B could be connected to the dsl modem via a router if that offered any advantages. The next two possibilities use both routers.

2) Connect NIC-B to a router on a different subnet and connect the two routers (Comcast and AT&T), disabling NIC-A. SmartFTP would use the AT&T router for uploads and RDC sessions would use the Comcast router and then connect to the PC via the AT&T router?

3) Connect NIC-B to a router on a different subnet and connect the two routers (Comcast and AT&T), leaving NIC-A connected to the Comcast router. Somehow tell SmartFTP to use the AT&T router for uploads and RDC to use the Comcast router?

Limit the upload speed. Go to the favorite properties. Then go to the Transfer dialog and set the upload limit.

For a dual WAN setup you need to manually configure the routing table or you can purchase a dual WAN router and set the QoS according to your requirements. But in summary it's not something trivial to setup.



Thanks for that advice. When I limit the SmartFTP upload speed or even pause the upload I still get lots of latency which shows up as sluggish response time.

If I run it shows that throughput is acceptable (9mbps up, 6mbps down) but latency is a problem with ping times of 300 ms or so. Stopping the SmartFTP upload or closing SmartFTP restores ping times to the 3 to 1 ms range.

Am I missing something in my SmartFTP configuration? Or perhaps is this a Comcast or cable modem issue?

If you are uploading with the max bandwidth through an asynchronous connection (e.g. ADSL) the behavior you see is normal. A workaround is to limit the upload speed or to upgrade your internet connection. I recommend you talk to your web hosting provider for assistance.