Image #1: (click to enlarge!)|
The DSL-splitter will filter the DSL signals and pass them to the DSL-modem, and filter the normal "phone" signals, and put them to the usual telephone connectors, to be used by telephone, FAX, modem, etc. as usual. As the DSL and phone signals use different frequency hands, they can be used at the same time.
The protocol spoken between the DSL-modem and PC on the twisted-pair line is "PPP over ethernet" (PPPoE), which uses it's own protocol types that any TCP/IP stack will ignore it. Basically, it's PPP frames encapsulated in Ethernet frames - see RFC 2516 for the full description
Ethernet (Image #2a) usually acts as a broadcast medium and PPP (Image #2b) is designed for bit-sequential media. Because of this difference, a facility is needed to encapsulate PPP-frames in ethernet frames and to forward packets between the ethernet- and PPP-layer. That facility is depcited as the green line connecting ethernet and PPP in Image 2c. The 'mouse-pppoe' program can be used for that, it's available as pkgsrc/net/mouse-pppoe in the NetBSD Packages Collection; An alternative program (not described here) is in pkgsrc/net/rp-pppoe. They access the ethernet layer by hooking in via the BPF interface, and provide a pty-interface for the PPP daemon (pppd) to connect to.
Image #2: (click to enlarge!)|
# cat /etc/ppp/pap-secrets 'AAAAAAAAAAAATTTTTTTTTTTTMMMM@t-online.de' * 'XXXXX'
|Where ...||means ...|
|AAAAAAAAAAAA:||"T-Online Anschlusskennung", 12 digit number, e.g. 000120123456|
|TTTTTTTTTTTT:||"T-Online Nr", 12 digit number, e.g. 3200123456. Often starts with "32"; if yours is less than 12 digits, add a '#')|
|MMMM:||"Mitbenutzer-Nummer", usually "0001"|
|XXXXX:||Password of your T-Online account|
Your login is now all three parts put in a row, with no seperator ("AAAAAAAAAAAATTTTTTTTTTTTMMMM"), e.g. 0001201234563200123456#0001. See http://www.netbsd.org/Documentation/network/#t-online for a more detailed description of the username.
You will also want to choose an appropriate set of options for /etc/ppp/options, e.g. you will have to add "noauth". See pppd(8) for a documented list of all options.
# pppoe -if rtk0 -name "AAAAAAAAAAAATTTTTTTTTTTTMMMM@t-online.de"Here, rtk0 is the device name that your network card is recognized as by NetBSD. A list of ethernet devices found by your system at boot time can be obtained by both typing "dmesg" and "ifconfig -a", see the dmesg(8) and ifconfig(8) manpages for more information.
The pppoe command will start up pppd, and make it talk to the DSL-modem, logging you into the network, i.e. authenticating you to your ISP, setting your local Internet address, etc. If you want to run any commands after the connection is established, put them into /etc/ppp/ip-up.
Now you're online using DSL technology - enjoy your fast connection! :)
If you want to shutdown your network connection, just interrupt the pppoe process by typing Control+C.