[ovs-discuss] multicast problems with OVSIntPort

[Gurucharan Shetty]

That is a little weird.
I hope someone that understands kernels well will reply.

On Fri, May 9, 2014 at 1:40 AM, Dietmar Maurer <dietmar at proxmox.com> wrote:
>> > In either case, just the
>> > "multicast" traffic should not have any negative effect.
>>
>> tcpdump reveals that corosync packets have wrong cksum:
>>
>> # tcpdump -envv "port 5404" -i test1
>> 07:50:59.927572 be:94:dc:b2:f8:8c > 01:00:5e:40:a6:1e, ethertype IPv4
>> (0x0800), length 161: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17),
>> length 147)
>>     10.11.12.1.5404 > 239.192.166.30.5405: [bad udp cksum 0xac7b -> 0x36e2!]
>> UDP, length 119
>
> I just noticed that I get bad checksum also with 'config1', so that cannot be the reason.
> Any idea why we get bad checksum - is that normal?
>
>> The nodes are directly connected using a crossover cable, so there is no
>> switch involved.
>
> The bug somehow depends on kernel and network card/driver, for example
> using igb 5.1.2 work with kernel 3.10, but fails with kernel 2.6.32:
>
> /lib/modules/2.6.32-29-pve/kernel/drivers/net/igb/igb.ko ==> fails
> /lib/modules/3.10.0-2-pve/kernel/drivers/net/ethernet/intel/igb/igb.ko ==> works
>
> The bug always triggers when I use Broadcom Tigon3 tg3.ko 3.132.
>
> So 'config1' works always, and 'config2' depends on kernel/driver.
>
> And idea how to debug that?
>
>