VPN using A T & T Cable Internet

The stability issue rests with the link to your ISP and your ISP itself. Cable is a shared medium and more people attached means less bandwidth available. Your response will fluctuate due to load on your cable and also on the internet itself. Oneof my customers has a vpn installed, and they traverse 12 intermediate points to get from one site to the other. ping response varies from 80 ms to 400 ms, and sometimes goes beyond the 2 sec ping response limit. Cable is an "always on" system, you also need to be prepared to implement tighter security than you would with a frame relay connection. Without knowing your traffic needs, it's hard to say if this would be an improvement for you. An upgrade to your frame relay link may be the easiest and best. For the customer I mentioned, a VPN works well. They got a dedicated T-1 link to the ISP and replaced a dedicated T-1 line between the sites. They're now saving approx. $15k/month in circuit costs with only a small degradation in performance. Best wishes.
- ck

The people who are telling you cable is unstable and slow are the ones trying to sell you DSL.

More to the point, is cable available? Many local cable companies will not provide business service, or will not run cable into a business address, andcannot or will not provide a static IP address. This would mean that you could use cable (if available) for your branch offices, but you would need some service which would give you a static IP for your main location. If your VPN server does not have a static address, how will your branch offices address it?

My company's solution is to use T1 or DSL for the main sites for internet, Frame Relay between our biggest sites, and put branch offices and remote users on cable or dsl, as available. As we add offices or as conditions change, we do a new cost-analysis.

Frame Relay is a guaranteed workable solution, but it is very expensive. The advantages are that it can be installed almost anywhere, and that it is extremely reliable. The disadvantages are cost, inflexibility, and (typically) long contracts.)

Cable is cheap, generally reliable, generally faster than DSL, but hard to get in business locations, and hard to get static IP's on.

DSL is generally cheap (depending on speedand type), you can generally get a static IP if you need one, but is distance limited. If you are too far from the phone office, you cannot get it, or cannot get the speed you want.

You pay your money and take your choice.

Good luck.

Running your VPN on cable access will be cheaper for sure, when you say you have had no problems with your cable access, is that just at one location or at the three? Because its a shared resourse it depends on all 3 of your locations to be ok. In any event, frame relay will be more expensive, so I would look at using either cable or DSL.

Most of my installs are on T1 or Frame, but I have started using dsl and running a vpn over the internet, and I was warned it would be slow and not reliable, and so far it is working fine. Also alot depends what kind of app you are running across it, as some accouunting softwares will not function without x amount of bandwidth when needed.
Before I go ahead I would discuss this with your provider aswell, but just for cost reasons I would give the cable a try
Good luck