Xen project Mailing List

On May 30, 2007, at 4:07 AM, Stephen Strowes wrote:

Hi,

On Wed, 2007-05-30 at 03:04 -0700, Jayson Vantuyl wrote:

You shouldn't have an IP on xenbr0. It shouldn't have multicast
turned on either. This might be part of the problem. Did you do
this or is this happening automatically?

This happens automatically; this is how the network scripts set up
xen-br0.

Note that this is xen 2.0 rather than a more recent version. I've seen
suggestion that multicast didn't work under older versions of Xen. Is
that accurate?

Cheers,
-S.

On May 29, 2007, at 3:22 AM, Stephen Strowes wrote:

Hi,

I've been searching for a solution to my problem, but as yet have not
found it. I've seen suggestion via Google that my version of Xen might
not support what I'm trying to do. Here goes anyway:

I have a bunch of VMs running over a handful of physical machines. I'm
using bridging as an easy way to give domU's access to the network. I
can't get the physical machines to forward the multicast traffic
generated by the virtual machines.

My domU's can all route multicast traffic between each other provided
they're hosted on the same physical machine, but multicast traffic
doesn't seem to be routed over xen-br0 to dom0, nor from dom0 back
into
the domU's.

Given that I can multicast traffic within the scope of one physical
machine, but not outwith, I assume what I need is to get xen-br0 to
forward multicast traffic. But how?

Below is a bunch of (hopefully) useful information:

dom0 Kernel version:
Linux nsmc16 2.6.11.10-xen0 #1 Thu May 10 15:45:26 BST 2007 i686
i686 i386 GNU/Linux

example domU kernel version:
Linux nsmc71.dcs.gla.ac.uk 2.6.11.10-xenU #1 Thu May 10 15:48:40
BST 2007 i686 i686 i386 GNU/Linux

ifconfig outputs:
eth0 Link encap:Ethernet HWaddr 00:12:3F:68:36:96
inet addr:130.209.251.16 Bcast:130.209.255.255 Mask:255.255.240.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:12569448 errors:0 dropped:0 overruns:0 frame:0
TX packets:2034982 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1834684880 (1.7 GiB) TX bytes:594688573 (567.1 MiB)
Base address:0xdcc0 Memory:dfbe0000-dfc00000

xen-br0 Link encap:Ethernet HWaddr 00:12:3F:68:36:96
inet addr:130.209.251.16 Bcast:130.209.255.255 Mask:255.255.255.255
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:11277419 errors:0 dropped:0 overruns:0 frame:0
TX packets:92312 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1057505519 (1008.5 MiB) TX bytes:7820231 (7.4 MiB)

And an example vif:
vif30.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:553608 errors:0 dropped:0 overruns:0 frame:0
TX packets:11544969 errors:0 dropped:15753 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:404685898 (385.9 MiB) TX bytes:1246144262 (1.1 GiB)

Might anybody be able to shed some light on this issue? I can't
upgrade
to a newer version of xen, unless the upgrade is trivial. The
closest to
my problem which I have seen is:
http://lists.xensource.com/archives/html/xen-users/2006-11/
msg00510.html, which received no responses.

Cheers,
-S.

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Re: [Xen-users] Multicast