Modem bank setup

[TheTraveler]

Hi everyone,

I am looking at setting up a modem bank using an 800 number for my remote staff to dial into the network. The problem is I have no experience in telephony and can't seem to find any info anywhere. I was wondering if anyone has any experience in setting up a modem bank and what software/configuration to use and such? Or maybe a good site to refer me to? Thanks!

 

[pansophic]

It all depends on what you really need, how large your enterprise is, and what types of equipment you are familiar with.

For most small enterprises, a simple Comtrol RocketModem card or Equinox card with 4 or 6 modems installed in their server is sufficient for RAS.

If your network is somewhat larger, and you really need the 56K connections, a digital modem emulator in a Cisco 3600 with a PRI T-1 connecting in to it is a good solution.

For higher-end enterprises, a dedicated access server, like an AS5X00 or Ascend Max with 1 or more T-1s connecting to it is appropriate.

Of course I still prefer a VPN with the user getting their own internet access as a superior solution. It is generally less expensive and more secure.


pansophic

 

[TheTraveler]

Sorry for the late reply, Holidays and all. Thanks Pansophic. We are a small enterprise, and have about 12 remote users who are either periodically or exclusively using dialup connections for work. It was suggested that I pursue a modem bank possibility as it would be cheaper, but you say it's actually more expensive? I am maintaining 12 dialup accounts at the standard $22 a month or so. We are looking at this as a solution because of the nature of our business, I can't/won't allow VPN completely into the network. And I have heard complaints of the speed of Exchange Mail through the VPN on dialups. I was thinking I could set up a stand alone server solely for remote access. So all I need then is one of the cards you suggested, 4-6 modem cards and RAS setup on the machine? I assume the cards you suggested are what is used to handle incoming calls and route to a modem card? Maybe I'm confused. Would you know of a site where I could learn more about how a modem bank works and such? Thanks for the help!

 

[pansophic]

What most people do not realize about dialup modems, is that if you use analog modems for your modem pool, you will never achieve rates higher than 33.6K. So dialup directly to your network will be excrutiatingly slow.

A VPN is more secure than a dialup connection, because the authentication is typically better. Unless you are using something like SecureID on your dialup access. Again, this is probably cost prohibitive in your application.

To achieve 56K for dialup, you have to terminate the connection digitally, and use modem emulators. These devices are expensive (compared to modems). Plus, you need to either pay to have a T-1 delivered to your dialup solution, or you have to buy a digital line card for your PBX to connect to the modem pool (again, probably cost prohibitive).

The Comtrol RocketModem is 4-8 modems on a single PCI card. They use a custom ASIC to multiplex the modem signals onto the PCI bus. The driver allows you to address each of the modems on the card as if they were separate COM ports. These cards are more expensive than 4 or 8 individual modems, but you can only install one WinModem on a PCI bus, so your only alternative is to use a multi-port serial card and external modems. This is at least as expensive, and it is a real hassle to find power for the external modems, and all of the cable connections make it error prone.

http://www.comtrol.com/products/hardware/rm_iii.asp

http://www.equinox.com/Dial_Access_Services91.html

http://www.cisco.com/en/US/netsol/ns340/ns394/ns6/ns122/networking_solutions_package.html

If your users are only doing mail through this connection, then you may want to switch them to IMAP, rather than POP.

Also, $22 a month is a pretty expensive dialup access. There are numerous providers who setup national accounts at $10 a month, although you do have to check on the cities that they provide access in. Plus, you usually end up needing to provide Internet access for your users on the road in addition to your RAS connection, unless you will let them browse the Internet as well. At 33.6K, they won't be doing much browsing.


pansophic