[Bridge] bridge, vlan and *no* stp/bpdu
Jonathan Thibault
jonathan at navigue.com
Fri Mar 7 11:47:21 PST 2008
Hello list,
I've posted here about this before, but I realise that it may have been
assumed that the bridged vlans simply put a switch port in a blocking
state and left my question ignored. So to recap.
I have two tg3 interfaces named 'in' and 'out' and a bridge named 'br0'
My vlan trunk is on the 'in' side of the network, and set as in.2, in.3
... The 'out' side goes straight to an ipv4 gateway on untagged plain
ethernet.
Putting 'in.2' and 'out' on the bridge works quite well and is roughly
what I've been using so far.
# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.00e081342870 no out
in.2
If I add in.3 to the bridge, trouble starts. The bridge keeps
forwarding packets just like it should, with the exception of ARP
replies from the gateway to machines in vlan 2. Machine that had ARPed
the gateway prior to adding in.3 to the bridge keep working fine.
Here's the strange thing however. Running a tcpdump on 'out' 'br0' or
in.2 shows me the arp requests *and replies* for the machines that do
not work, however, if I look on the wire leaving the 'in' interface
itself (using a hub and another box), the arp replies are nowhere to be
found.
So the arp replies get eaten *before* they make it onto the wire, but
*after* tcpdump saw them on in.2. It's driving me nuts... I thought it
might have to do with the tg3 hardware doing some funky vlan
acceleration, but I've seen the same on plain dumb NICs too.
I'm willing to pay for a solution to this... Or even for just someone
knowledgeable enough with the code taking interest in the issue.
Thanks,
Jonathan
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