Testing lagg

Hello.

I've got a new box which features two gigabit ports and I
though I'd try 
lagg with LACP.

On the box I put the following in /etc/rc.conf:

ifconfig_em0="up"
ifconfig_em1="up"
ifconfig_lagg0="laggproto lacp laggport em0 laggport
em1 192.168.100.101 
netmask 255.255.255.0"


Then I aggregated the ports on the switch (3com).


This seems to work fine, although I see a 30 seconds delay
from the 
moment a network cable is unplugged and the moment the
network works again.
Is this normal? Can this time be reduced?
Any other hint or gotcha?



  bye & Thanks
	av.
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On Wed, May 28, 2008 at 05:28:34PM +0200, Andrea Venturoli
wrote:
> Hello.
> 
> I've got a new box which features two gigabit ports and
I though I'd try 
> lagg with LACP.
> 
> On the box I put the following in /etc/rc.conf:
> 
> ifconfig_em0="up"
> ifconfig_em1="up"
> ifconfig_lagg0="laggproto lacp laggport em0
laggport em1 192.168.100.101 
> netmask 255.255.255.0"
> 
> 
> Then I aggregated the ports on the switch (3com).
> 
> 
> This seems to work fine, although I see a 30 seconds
delay from the 
> moment a network cable is unplugged and the moment the
network works again.
> Is this normal? Can this time be reduced?
> Any other hint or gotcha?

Does the switch have spanning tree enabled?

Regards,

Gary
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On Wed, May 28, 2008 at 05:28:34PM +0200, Andrea Venturoli
wrote:
> Hello.
> 
> I've got a new box which features two gigabit ports and
I though I'd try 
> lagg with LACP.
> 
> On the box I put the following in /etc/rc.conf:
> 
> ifconfig_em0="up"
> ifconfig_em1="up"
> ifconfig_lagg0="laggproto lacp laggport em0
laggport em1 192.168.100.101 
> netmask 255.255.255.0"
> 
> 
> Then I aggregated the ports on the switch (3com).
> 
> 
> This seems to work fine, although I see a 30 seconds
delay from the moment 
> a network cable is unplugged and the moment the network
works again.
> Is this normal? Can this time be reduced?
> Any other hint or gotcha?

Can you post a verbose ifconfig (-v) for hte before and
after. It will
show the lag identifiers which may help diagnose this.


Andrew
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Gary Palmer ha scritto:

> Does the switch have spanning tree enabled?

Yes.
Should it be?

  bye & Thanks
	av.
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Andrea Venturoli ha scritto:
> Gary Palmer ha scritto:
>
>> Does the switch have spanning tree enabled?
>
> Yes.
> Should it be?
>
>  bye & Thanks
>     av.
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> http://lists.freebsd.org/mailman/listinfo/freebsd-net
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>

Well, the latency then could be related to spanning tree
protocol not 
immediatly
forwarding traffic to the new port due to topology change.
Try to 
disable it on the switch.


Daniel

-- 

WBR,
Cordiali Saluti,
 
Daniel Ponticello, VP of Engineering

Network Coordination Centre of Skytek

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On Thu, May 29, 2008 at 11:05:18PM +0200, Andrea Venturoli
wrote:
> Gary Palmer ha scritto:
> 
> >Does the switch have spanning tree enabled?
> 
> Yes.
> Should it be?

It can be left on but if you can disable it on the ports
that you
are using for lagg then that should help.  If you can't turn
it off on
a per-port basis and you don't have a meshed switch topology
then just
turn spanning tree off.  I think whats happening
is spanning tree is seeing a topology change and forcing a
renegotiation of the tree, which has the side effect of
stopping
packet forwarding.  You could also turn down the spanning
tree timers,
but there would still be a pause in the forwarding of
packets

Regards,

Gary
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