[ovs-discuss] [EXT] Re: How to match on the physical and logical ingress ports

Ben Pfaff blp at ovn.org
Thu Jul 8 19:12:13 UTC 2021


Ah.  I recognize what you're trying to do now.  OVS doesn't have good
support for the push/pop model for tunnels.  The "encap" action is a
start at this, but it currently supports only nsh and I'm not convinced
that the implementation is high quality.

On Thu, Jul 08, 2021 at 05:35:27PM +0000, Dr. Helen Chen wrote:
> When my OVS contains both gre and the physical interface, packets match on in_port=physical-intf, rather than in_port=gre.  Is there a way to force the packet to be matched on gre and have them recognized as tunneled packets?  I tried resubmit and mirroring, but they didn't work.
> 
> For what it's worth, what I want OVS to do with respect to GRE is more like pushing/popping MPLS labels based on routing, instead of bridging, assuming that mixing packets in different domains means mixing packets in different bridge domains.
> 
> Thanks,
> Helen
> 
> On 7/7/21, 12:27 PM, "Ben Pfaff" <blp at ovn.org> wrote:
> 
>     It's possible but not widely done, since it doesn't generally make sense
>     from the perspective of mixing packets in different domains.  I don't
>     know anyone who does it.
> 
>     On Wed, Jul 07, 2021 at 03:38:39PM +0000, Dr. Helen Chen wrote:
>     > In the OVS documentation quoted below, it states that "physical ingress ports (which need not be part of any switch)...".
>     >
>     > Is it correct to assume that the physical ingress port (of the gre tunnel) can optionally be part of the switch that also has the gre tunnel?  If so, is there documented example configuration?  (So far, I've only seen OVS configuration where switch consists of only gre tunnel but not the physical ingress port of the tunnel.)
>     > 
>     > Thanks,
>     > Helen
>     > 
>     >     -----Original Message-----
>     >     From: Ben Pfaff <blp at ovn.org> 
>     >     Sent: Friday, July 2, 2021 1:46 PM
>     >     To: Dr. Shukri George Abdallah <sabdallah at mitre.org>
>     >     Cc: ovs-discuss at openvswitch.org
>     >     Subject: Re: [EXT] Re: [ovs-discuss] How to match on the physical and logical ingress ports
>     > 
>     >     The documentation says this:
>     > 
>     >            A  packet’s  ingress  port and physical ingress port are identical except
>     >            for packets processed by a switch feature such as  bonding  or  tunneling
>     >            that  makes  a  packet  appear to arrive on a ``virtual’’ port associated
>     >            with the bond or the tunnel. For such packets, the ingress  port  is  the
>     >            virtual  port  and  the physical ingress port is, naturally, the physical
>     >            port. Open vSwitch implements both bonding and tunneling, but its bonding
>     >            implementation  does  not use virtual ports and its tunnels are typically
>     >            not on the same OpenFlow switch as their physical  ingress  ports  (which
>     >            need not be part of any switch), so the ingress port and physical ingress
>     >            port are always the same in Open vSwitch.
>     > 
>     >     For bonding, OVS in_port always matches on the physical input port.
>     > 
>     >     For tunneling, OVS doesn't pass along the physical input port but only the virtual one.  You might be able to set the packet mark in the physical bridge and then match on it in the virtual one, though.
>     > 
>     >     On Thu, Jul 01, 2021 at 06:04:29PM +0000, Dr. Shukri George Abdallah wrote:
>     >     > Hi
>     >     > 
>     >     > Please see https://opennetworking.org/wp-content/uploads/2014/10/openflow-switch-v1.3.5.pdf Section 7.2.3.9 .This link uses the term "logical"
>     >     > 
>     >     > Please see https://www.man7.org/linux/man-pages/man7/ovs-fields.7.html. This link uses the term "virtual".
>     >     > 
>     >     > The context is GRE tunneling
>     >     > 
>     >     > Shukri
>     >     > -----Original Message-----
>     >     > From: Ben Pfaff <blp at ovn.org>
>     >     > Sent: Thursday, July 1, 2021 1:37 PM
>     >     > To: Dr. Shukri George Abdallah <sabdallah at mitre.org>
>     >     > Cc: ovs-discuss at openvswitch.org
>     >     > Subject: [EXT] Re: [ovs-discuss] How to match on the physical and 
>     >     > logical ingress ports
>     >     > 
>     >     > On Thu, Jul 01, 2021 at 02:51:13PM +0000, Dr. Shukri George Abdallah wrote:
>     >     > > When the physical ingress port is different than the logical ingress 
>     >     > > port, using the ovs-ofctl utility, how can one match on the physical 
>     >     > > and logical ingress ports?
>     >     > 
>     >     > How are you defining "physical" and "logical" ingress ports here?  Out of context, it's not clear.
>     > 
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