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List:       linux-390
Subject:    Re: Two different vswitches in parallel
From:       Alan Altmark <Alan_Altmark () us ! ibm ! com>
Date:       2011-02-15 23:52:43
Message-ID: OF408AD77F.0D909025-ON85257838.0075C840-85257838.00832BCF () us ! ibm ! com
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On Tuesday, 02/15/2011 at 03:28 EST, Juha Vuori <juha.vuori@pp2.inet.fi>
wrote:

> > Why NOGVRP?  That prevents CP from telling the switch about the VLANs
in
> > use.
>
> Our network guys said they don't want that mainframe registers anything
in
> their switches..
> I'll have to talk to them again to check if they really knew what they
were
> saying. :)

They need to view the VSWITCH as a *switch*, not a mainframe.  The VSWITCH
isn't an IP stack.

> > "And the quarterback is toast!".  The traffic on VSW1 will be
untagged.
> > Untagged traffic on a trunk port will be assigned the native VLAN id
of
> > the physical switch.  You can bet it isn't VLAN 58 or 46 (probably
VLAN
> > 1).
>
> No no, linux hosts do vlan tagging, their network interfaces are
configured
> with vconfig, not
> ifconfig. And then vsw1, being vlan unaware, delivers vlan tags to and
from the
> linux hosts without
> modifying them. This is how I understand this.

VSW1 was defined WITHOUT the VLAN option, so it is VLAN unaware.  No
tagging is allowed by guests and no tagging is performed by CP.  The port
itself will tag the traffic.

> I guess this is not a recommended way to configure this, but this is how
it has
> been from the
> beginning. Vsw1 has been working well for three years now..

Depends on whether Network Guys changed you from access port to trunk
port.

> Our network guys said recently that they want linuxes to be vlan unaware
and
> vswitches to take care
> of vlan tagging. I agreed.
> Vsw2 is the newcomer, as we are migrating LPAR mode VSEs onto VM and
want to
> make their network
> connections redundant.

If you want to share a trunk port between two VSWITCHes, go for it (*I*
wouldn't do it), but use NOGVRP on both and configure both as VLAN-aware.

Alan Altmark

z/VM and Linux on System z Consultant
IBM System Lab Services and Training
ibm.com/systems/services/labservices
office: 607.429.3323
Alan_Altmark@us.ibm.com
IBM Endicott

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