We have a VPN running on 2 3COM firewalls (superstack III) between our LA and Long Beach offices. Our internet connection in LA is a T1 line and in Long Beach a DSL 1.5/384 line. The users in Long Beach are accessing an Access database through the VPN and they complained about the speed. We upgraded the DSL speed to what it is right now, but it is still too slow. What are your thoughts about this one?
Answer: There can be many factors here that can cause problems. To find the best solution you should consider hiring a consultant in your area to do a complete traffic analysis of your network. However, based on the information I have from your question, I will answer it this way. The problem as I see it is the DSL line. First of all the DSL line is running at about half the speed of the T-1 line (512K uplink and 512K downlink). But the real problem here is that DSL is a shared media line, which means you are competing with other customers in your area for this 512K bandwidth. Your T-1 in LA, is a dedicated 1.544Mbs leased line that will provide the full bandwidth minus overhead (approx. usable bandwidth 1.35Mbs) to your users. My suggestion to you would be to acquire a T-1 line for the Long Beach office also. If T-1 is too expensive, then inquire about a fractional T-1. You may still only get 512K with a fractional T-1 line, but at least it will be dedicated to your office and therefore should provide better response time to your users. Bear in mind, that increasing the speed of you lease line is not always the fix to the problem.
This was first published in April 2002