Re: Ethernet Bridging

[DrFranken <midrange@xxxxxxxxxxxx>]

I would not recommend proxy ARP.

1) Most i Admins are confused by Proxy ARP.
2) It works at the O/S Level so it's going to use more overhead.
3) Most i Admins are confused by Proxy ARP.
4) You need to understand subnetting to make it work.
5) Most i Admins are confused by Proxy ARP.
6) It's not a very standard thing and will be hard to troubleshoot 
especially compared to Bridging.
7) Most i Admins are confused by Proxy ARP.

        - Larry "DrFranken" Bolhuis

www.frankeni.com
www.iDevCloud.com
www.iInTheCloud.com

On 8/20/2013 2:23 PM, Evan Harris wrote:

> If the guest partition and the host partition are on the same network
> (which they must be if you want to assign an address to the adapter) then
> you might be better using proxy ARP to assign an address to the guest.
> https://publib.boulder.ibm.com/iseries/v5r2/ic2924/index.htm?info/rzalm/rzalmtcpip.htm
>
> Personally I have found the Ethernet Bridging a really useful solution. The
> chief advantage is it allows me to use one PORT per multiport NIC for a
> partition (or partitions) rather than having to assign an entire card.
>
> I found the HEA a bit clunky but only used t a couple of times.
>
>
> On Wed, Aug 21, 2013 at 5:10 AM, Mitchell, Dana <dmitche@xxxxxxxxxx> wrote:
>
> > Has anyone worked much with 'Ethernet Bridging Between IBM i Host and IBM
> > i Guest'?   We are working on adding a 2nd LPAR to a production machine and
> > I thought it would be a good idea to just one an Ethernet port on the first
> > machine and bridge traffic from it to the new LPAR.  After doing some
> > research on the subject, I found this document:
> > http://www-01.ibm.com/support/docview.wss?uid=nas8N1011193  it explains
> > what needs to be done very well but comes with one caveat:
> >
> > Important Note: IBM suggests that the selected Ethernet resources be used
> > for only layer-2 bridging and not for IBM i TCP/IP configuration. There is
> > a significant increase in processor usage for any host traffic that uses
> > bridged resources. In addition, any line description that is used for
> > bridging receives many frames that are not useful to the TCP/IP stack.
> > These frames use unnecessary processing resources. The virtual Ethernet
> > line on the host does not require an interface. You only need the physical
> > and virtual lines active for the bridge function to work. You should not
> > have an interface on the physical line used for the bridge either. Create a
> > separate physical line & interface for network traffic on the Host.
> >
> > If I'm reading this correctly it seems IBM is implying that the bridging
> > function is too much overhead to both service the host partition with IP
> > traffic and bridge traffic from LPAR#2 also.   So by my math that makes
> > this facility pretty useless until you get to 3 or more LPARs.   Is anyone
> > doing this now, and can verify that is it or is not too much overhead?
> > Why oh why did they discontinue HEA?
> >
> > Dana
> >
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