On Tuesday, 01/15/2008 at 03:33 EST, Brad Hinson <[EMAIL PROTECTED]>
wrote:
> Guests Linux01 and Router01 are both connected to VSWITCH vsw1.
> Router01 has connections to 2 other VSWITCHes, vsw2 and vsw3.  Both vsw2
> and vsw3 are on different subnets, and both have connections to the
> external network.
>
> The goal is to ping the outside from Linux01, using Router01 as a
> gateway (static links are setup on Router01).  Both vsw2 and vsw3 have
> PRIrouter set, but vsw1 doesn't (this is the one without real OSA
> attached).
>
> The network folks say the ping is leaving the OSA, and the reply is sent
> back.  However, the reply isn't making it back to Linux01.  Router01 can
> ping the outside okay.  'q vswitch vsw1' confirms there are tons of
> packets under 'Discarded', which led me to investigate the PRIrouter
> setting on vsw1.

You need to ensure that Router01 includes PRIROUTER in the LINUX device
driver configuration for the virtual NICs that connect to each of the
three VSWITCHEs.  When a packet comes into a Layer 3 VSWITCH that has
PRIROUTER on the DEFINE VSWITCH, CP will hand a copy of the packet to EACH
virtual NIC on that VSWITCH that has been tagged as PRIROUTER *by the
guest*.  (There is no CP setting to turn virtual NIC PRIROUTER on/off.  It
must be set by the guest's device driver.)

With any luck (as in your case), one of those guests has a link to the
subnet containing the destination IP.

Warning: You will get duplicate packets at the target with a Layer 3
VSWITCH if multiple guests have PRIROUTER and are both connected to the
same back-end subnet.  With Layer 2, the outside world will send the
packet to ONLY Router01, no dups are sent, AND you don't have to worry
about PRIROUTER any more.

Alan Altmark
z/VM Development
IBM Endicott

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