Connecting to the world

Beagleblog

Mar 20, 2009 GMT
Oliver Frommel

Controlling the Beagleboard over a serial line with a terminal program such as Minicom is working just fine, but it's much more convenient to have a real network connection. For instance to update the Linux distribtion on the SD card without having to unplug it and plug it into a PC's card reader. There's just one little obstacle to overcome: The board does not feature either an Ethernet port or a Wifi chip :)

Luckily the Linux kernel programmers are providing a solution to that problem for quite some time: You can use the USB interface for networking, too. So I just connect the Beagleboard to the computer with a USB cable in addition to the serial connection I am using to control the board. There's no need to load a kernel module or compile special software for this to work. The only thing left is to enter the following line into the terminal that connects to the board:

root@beagleboard:~# /sbin/ifconfig usb0 192.168.0.2 netmask 255.255.255.0

The same goes for the PC, just with a different address:

# /sbin/ifconfig usb0 192.168.0.1 netmask 255.255.255.0

That's enough to have a working connection between Beagleboard and PC, as you can see with the ping command:

$ ping 192.168.0.2
  PING 192.168.0.2 (192.168.0.2) 56(84) bytes of data.
  64 bytes from 192.168.0.2: icmp_seq=1 ttl=64 time=0.203 ms
  64 bytes from 192.168.0.2: icmp_seq=2 ttl=64 time=0.207 ms
  ...

To get on the Internet you need to configure your PC as the default router and set up Network Address Translation (NAT) accordingly. Setting the default route on the board is as simple as:

  root@beagleboard:~# route add default gw 192.168.0.1

The following commands will configure Masquerading on the PC and activate IP routing in the Linux kernel:

# iptables --table nat --append POSTROUTING --out-interface wlan0 -j MASQUERADE
    # iptables --append FORWARD --in-interface usb0 -j ACCEPT
    # echo 1 > /proc/sys/net/ipv4/ip_forward

Beware that I am using "wlan0" here as the outgoing interface, as my PC has a wireless connection to the Internet. Depending on the brand of hardware you might need to write "wmaster0" here, or just "eth0" if you are using an Ethernet connection.

To conveniently make use of host names instead of plain IP addresses you need to add the IP address of a nameserver to the Beagleboard's "/etc/resolv.conf" configuration file. If it's working you can start an update of the Angstrom distribution with "opkg update".

Comments

  • Had no idea the Beagleboard

    Had no idea the Beagleboard could network over USB. I just figured I wouldn't be using any networking with it, now I have a solution.
  • what about if your pc is already on a network witht he same subnet as your example

    what about if your pc is already on a network with the same subnet as your example? Whenever i try to set the ip (im on windows too) it clashes with my Local Area Connection 1 settings. My LAN1 settings are Ip: 192.168.1.20, subnet 255.255.255.0, gateway 192.168.1.100
    Now what would you suggest as suitable ip for LAN2 (beagle gadget adapter) and for Beagle Ifconfig?
  • How to save?

    After settings how to save them for later use? (when rebooting BB I should do settings again!)
  • No config necessary(?)

    As in the post by Tyler W. Wilson, I use the 3-port combo USB hub with my beagleboard,
    and after cabling the hub to my router (Airport Extreme) and booting the Beagleboard,
    it was on the network. I ssh-ed to the beagleboard and did opkg update, worked perfectl

    I expected to have to do some configuration, but the thing just came up on the network.



  • Ethernet in ubuntu

    I tried the commands above in a beagleboard running ubuntu 9.04 with no result. I dont even get the "link" signal when I plug the ethernet cable to a switch. Do you know if I have to install anything else to make it work ? Thanks in advance
  • Connecting via SDIO...

    Thank you for these tips - it helped me fix the case where my BB comes up with the ability to resolve names, but not actually perform network requests. It is odd - sometimes the board comes up fine, and sometimes it does not.

    Note the previous question, and my answer: you need both the min A OTG to miniB adapter, plus a USB to Ethernet adapter. I bought the suggested one that has the 3 USB ports and Ethernet port. It works well for me, since in addition to mouse and keyboard, I can power the BB with it too (via a USB to power adapter [see https://specialcomp.com/beagleboard/RevB.htm]).

    Also note that in my case I used the Angstrom build too. And one nice feature is that it appears that a VNC server is loaded and executing by default. So with the Ethernet connection working, one does not even need the keyboard or mouse directly connected to the BB. Which brings me to my next dream:

    I have both a Spectec SDIO WiFi card, and a Palm SDIO Bluetooth module. What I would _really_ like to do is use the SDIO WiFi card instead of the wired Ethernet connection. With the Linux kernel and rootfs in NAND, this would make a very nice stand-alone controller board. I have tried plugging in the SDIO card, but I do not know enough about Linux to know how to get the proper driver loaded.

    Any suggestions?

    Thank you,
    Tyler
  • No special hardware needed

    It's just a regular USB cable, no special hardware needed - so far. It's USB A and Mini B plugs as far as I know ("a big one and a small one"blunk. That's enough for networking. If you want to attach keyboard and mouse, that's a different story I will soon be blogging about.
    Thanks for your interest.
    Oliver

  • confused ... no extra hardware needed ?

    I'm confused! How do you connect the beagle board with your pc for networking ?
    No need special/extra hardware ? What kind of usb cable are you using ?
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