vlan taggging on etherchannel

Tom Judge tom at tomjudge.com
Tue Aug 21 04:51:34 PDT 2007

Arne Schwabe wrote:
> Tom Judge schrieb:
>> Mohacsi Janos wrote:
>>> Dear All,
>>>     What is the recommended way to configure vlan interfaces on
>>> etherchannel bonded interfaces in a failure mode. I found, that
>>> etherchannel is supported by ng_fec(4) (but not exactly what I want)
>>> and also found that there two? way of configuring vlans: vlan(4) and
>>> ng_vlan(4). But I did not found any description or configuration
>>> snippet to configure both preferentially via /etc/rc.conf neither in
>>> FreeBSD 6.x-stable, neither in FreeBSD-7.0-current. What I want to
>>> achieve:
>>>   [switch1]-----GE---bge0----\    /----vlan100
>>>                               }=={-----vlan101
>>>   [switch2]-----FE---bge1----/    \----vlan102
>>>                                    \---vlan103
>>> I would like to  prefer all the vlans via bge0 with GE towards
>>> switch1. And use only bge1 in case of switch1 or bge0 link failure.
>>> I could use bond on Linux for this purpose. How to achieve similar
>>> setup?
>> You may want to take a look at if_lagg, it supports EtherChannel (AKA
>> fec), LACP and failover modes (Which is what you would need).  It is
>> available in RELENG_6 and Current.
> If the switches don't support LACP/Fec over two devices use bridge_stp
> to simulate a switche and let spanning-tree do the failover.
> Arne

Spanning tree may not select the GigE connection as the primary 
connection and use the FastE connection instead. if_lagg with 
laggproto=failover will do exactly as specified,  use bge0 when the link 
to the switch is good, and fail over to bge1 when bge0 goes down.  There 
is no switch side support required for this configuration.


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