[clug] Network bridges behind wireless ethernet bridges
Edward C. Lang
edlang at edlang.org
Sat Dec 17 05:24:59 MST 2011
On 17/12/2011 18:08, Dale Shaw wrote:
> On Sat, Dec 17, 2011 at 5:31 PM, Edward C. Lang<edlang at edlang.org> wrote:
>> I'm a little puzzled by a problem I've run into this afternoon in the
>> process of setting up some a new computer and some virtual servers.
> [... stuff ...]
> The topology seems simple enough at a bridging level.
> Definitely sounds like a MAC learning problem. Possibly some kind of
> ARP timer/MAC learning interaction.
> Does the connectivity only drop after a period of inactivity? When
> connectivity drops, is it only to the KVM host? That seems to be what
> you're saying.
Yup. For console SSH, I'd see "Write failed: Broken pipe". Other
applications (virt-manager, deluge) would just lose their connection,
generally at the most inopportune times! There was nothing in any log
files that corresponded with these connection failures.
> What kind of device is the wireless bridge?
* Asus RT-N12 running shibby's tomatousb build as the main AP
* Asus RT-N16 running shibby's tomatousb build as the wireless bridge
* KVM host is an HP Microserver running Ubuntu Oneiric with the most
recent server kernel / libvirt packages / qemu packages
Contents of /etc/network/interfaces:
# The loopback network interface
iface lo inet loopback
# The primary network interface
iface eth0 inet manual
# bridge device
iface br0 inet dhcp
I suffered the same problems with both static and DHCP IP address
assignment. The Ubuntu KVM and primary KVM documentation differs on
enabling or disabling spanning tree protocol; neither fixed the problem.
I also tried putting a bonded interface in between the physical and
Gus: the wireless bridge is very stable for other devices on it (PS3,
WDTV Live Hub, an old laptop). The bridge was also very stable before I
started virtualising the HP Microserver. I've pushed several hundred
gigabytes across it in the last month without issue, generally within
speeds acceptable for 802.11n networks. I had to swap the roles of the
RT-N12 and the RT-N16 as the opposite combination was extremely
unstable... the RT-N12 kept locking up.
I'll try capturing some packets tomorrow.
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