Asymmetric networking using Linux
The idea is simple, two subnets (separate networks) and then route packets from one to the other. The environment, however, is not symmetric. We wanted to contact a node on the other subnet and we could see the packets travelling over the switch to the router back through another switch to the node, but the node itself refused to reply.
Each node has two NICs and each NIC is connected to a separate network. If you try to connect or ping one node from another, Linux is smart enough to go directly over the NIC with the right network. If a NIC should ever fail, the failover is that the packets are then routed up one network to the router then over to the other network.
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Wireless BCM4312 3.2 kernel
Since there is an Ubuntu package ‘firmware-b43-lpphy-installer’ which is up to date and will work against the 3.0 kernel, my earlier posts are obsolete. If you are not running Ubuntu, then you will still need to reference my post.
The latest 3.2 Linux kernel however has a few ABI changes, most notably in the network stack which effects the Broadcom’s wl module. Most notably is: .ndo_set_multicast_list which was replaced with .ndo_set_rx_mode.
Wireless BCM4312 3.0 kernel
With the latest 3.0 kernel there is still no “out of the box” support for my BCM4312 wireless chipset. Nor is there any help from Ubuntu 11.04 leaving me to use Broadcoms hybrid driver with patch.
Chipsets supported by “Broadcom’s IEEE 802.11a/b/g/n hybrid Linux® device driver” are: BCM4311, BCM4312, BCM4313, BCM4321, BCM4322, BCM43224, and BCM43225, BCM43227 and BCM43228.
My specific chipset from lspci command:
Broadcom Corporation BCM4312 802.11b/g LP-PHY (rev 01)
Ubuntu 11.04 Natty with fglrx and 2.6.39
Natty (11.04) users can finally get fglrx playing nicely together with X.org 1.10. We can also make the latest driver work well with the 2.6.39 kernel.
Custom build procedure:
- Install the latest 2.6.39 kernel revision from Ubuntu Mainline or install the PPA.
- Download 64-bit 11.4.
- Extract the files from the package:
sh ./ati-driver-installer-11-4-x86.x86_64.run --extract ati - For 2.6.39 support, download this extra patch: 2.6.39_bkl.patch
- Check for Big Kernel Lock usage:
cat /lib/modules/`uname -r`/build/.config | grep -c CONFIG_BKL=y
If the result of this command is 0, then download no_bkl.patch as well. - then apply them:
cd ati; for i in ../*.patch; do patch -p1 < $i; done - Build your new ati/fglrx deb packages:
./ati-installer.sh 8.841 --buildpkg Ubuntu/natty - Install our newly created deb packages:
sudo dpkg -i ../fglrx*.deb - If your /etc/X11/xorg.conf is missing you will need to run:
sudo aticonfig --initial
and then reboot.
That newly created package should work for the entire 2.6.39 series.
Ubuntu 2.6.39 kernel and fglrx 8.831
For those 10.10 Maverick users with 2.6.38 or 2.6.39 (64-bit) kernels, you can get fglrx playing nicely together with X.org 1.9.
Unfortunately this new driver does not support X.org 1.10 and that leaves 11.4 users to use the open-source drivers.
Custom build procedure:
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