How is your DSLAM configured?

You can see the entire config.txt file (with some items changed or x'd out for security reasons).

Most of the configuration is straightforward. For example, each SDSL port is configured with RFC 1483 encapsulation. We are using an IP netmodel, which takes up four IP addresses per port but avoids worries about IP address spoofing by users.

There is one way in which our DSLAM configuration is different from the usual configurations. In a more typical configuration the default route (connection to the Internet) is by means of an ethernet port in the system control module (port number 1.3.1.0). But in our configuration the connection to the Internet is by means of one of the SDSL ports, namely a port which is connected to a home where there is a point-to-point microwave link to an office where there is a T1 line to the Internet. In our case it is SDSL port number 1 (port number 1.4.1.0). The IP address of that port is 10.0.1.2 with a netmask of 255.255.255.252. Thus the default route is set as:

set ipRouteTable [0.0.0.0] NextHop=10.0.1.1 Mask=0.0.0.0

Unfortunately it is not possible to set this default route by means of the CopperView interface. The only way to set it is by means of keyboard entries at the craft terminal.

How do you configure your DSLAM to work with G.Lite modems?

A chief challenge is that although the Copper Mountain web site suggests that lots of ADSL and G.Lite modems will work with the CopperEdge cards, we tried a lot of them and were unable to get them to work. The only modem that we were able to get to work with our G.Lite card was the Alcatel Speed Touch Home modem.

If you previously worked only with SDSL modems, there is something different with ADSL and G.Lite modems. They require you to set up an ATM VPI/VCI (virtual circuit). We arbitrarily selected a VPI of 0 and a VCI of 35, simply because that was how most of our Speed Touch Home modems were configured. You have to set up the same VPI/VCI in the DSLAM port and in the modem itself. Here is the line from the config file that describes setting up an ATM virtual circuit:

set cmAtmVclTable [1.5.2.528] Vpi=0 Vci=35 AdminStatus=Up \ TransmitTrafficDescrIndex=0 OAMAdminState=disabled OAMAutoLBState=disabled \ OAMLBInterval=5 OAMLBTimeOut=15

In this example there is a PII (permanent interface identifier) which uniquely identifies an interface on the DLSAM. The first part "1" is always 1. The second part "5" is the shelf number, in this case the fifth shelf (the space for the second line card in our CE-150). The "2" is the port number in that card. The last part is the number of the virtual circuit itself, which must be 528 because you are using RFC1483 encapsulation.

It is quite easy to forget to set up the VC, if your previous work is with SDSL. You can set up a telco shared-loop circuit, connect the DSLAM port at one end, and connect the G.Lite modem at the other end, and the "link" lights turn green at both ends. So why can't you ping between the IP devices at both ends? The answer is you forgot to set up the VPI/VCI in the DSLAM for that port.