Why can't I get this DSL Modem to work?
It has come to my attention that there are a vast number of people out there who cannot get their independently-purchased DSL modems or gateways to work with their DSL providers. (For those who do not know what a gateway is, it is a device that is both a modem and router in one unit. 2Wire makes a number of models of gateways that are used by AT&T for their DSL services. From this point forward, when I refer to DSL modem, understand that I mean gateways as well.) These people complain that the modems are not compatible or defective. Well, as a network engineer, let me tell you that is most often not the case.
A DSL modem is much more complex than something as simplistic as a dialup or cable modem. With either of those, it's pretty much plug and play. However, with a DSL modem, there are several parameters that need to be set correctly to allow proper operation. Because of this, most DSL modems have the ability to auto-sense most of the parameters that fit the DSL line profile. If auto-sense does not work for some reason, then you need to contact your DSL company and ask for the following parameters:
VCI (Virtual Channel Identifier)
Service Category (UBR without PCR, UBR with PCR, CBR, Non-Realtime VBR, or Realtime VBR)
Peak Cell Rate (if anything but UBR without PCR)
Sustainable Cell Rate (if either VBR category)
Maximum Burst Size (if either VBR category)
Protocol (PPP over Ethernet (PPPoE), PPP over ATM (PPPoA), IP over ATM (IPoA), or Bridging)
Encapsulation Type (LLC/SNAP, VC MUX)
Dynamic IP or Static IP
IP Address (if Static IP)
PPP Username
PPP Password
Session Establishment (Always On, Dial on Demand, Manually Connect)
If any of these parameters are set incorrectly, chances are that you will not connect to your DSL provider.
The modems installed by the DSL providers are typically very good quality (Cayman, 2Wire, Motorola, Siemens/Efficient Networks, etc.), so most people can keep their original modems until they either are no longer able to access the DSL service (due to some change made by the DSL provider that is beyond the capability of the modem) or the modem fails.
The only exception to this is that if you feel that your DSL connection is slower than you think it should be and your DSL provider tells you that your line is fine, you might consider replacing your modem with a newer one. The reason being that if you have had your modem for awhile (say, three to five years), it may be incapable of attaining the faster speeds that you are now able to use.
A perfect example is an installation we did today for a client. He had both a 2Wire HomePortal 1000S gateway and a Siemens/Efficient Networks SpeedStream 5360 modem while subscribed to AT&T's Internet Elite service. This Elite package promises DSL speeds up to 6Mbps downstream and 512Kbps upstream. However, he was getting only about 2.5 to 3Mbps down and 256 to 300 up. Part of the problem was determined to be a line problem, which AT&T fixed before I arrived on site, but that allowed his speeds to get up to only 4Mbps down and 384Kbps up, still not acceptable. Seeing that he had two modems, we tried both and got the same results. I let the client know that the best option was to replace the modem with something newer, specifically the Netgear DM111P. We installed that modem and configured it correctly in about three minutes. This had him up and running at full speed. We ran speed tests from various places: AT&T, Testmy.net, speedtest.net, and speed.sunflower.com (the speed test on the local cable company's server). All came in reading between 5.5 and 6.1Mbps. (Yes, in a couple of the tests we conducted, the speed actually came in at 6.1Mbps even though he is subscribed to only 6.0. According to the modem, the line is actually capable of attaining over 9Mbps if the gates are opened by AT&T to allow that.)
Configuring a DSL modem is not something easily accomplished without proper experience and knowledge, so give Best Deal Computers a call. As long as you are in the Douglas County (Kansas) area, we will gladly come out and help you with your modem.