John McDowall <jmcdow...@paloaltonetworks.com> wrote on 05/26/2016 10:59:48 AM:
> From: John McDowall <jmcdow...@paloaltonetworks.com> > To: Ryan Moats/Omaha/IBM@IBMUS, Ben Pfaff <b...@ovn.org> > Cc: "discuss@openvswitch.org" <discuss@openvswitch.org>, Justin > Pettit <jpet...@ovn.org>, OpenStack Development Mailing List > <openstack-...@lists.openstack.org>, Russell Bryant <russ...@ovn.org> > Date: 05/26/2016 11:00 AM > Subject: Re: [OVN] [networking-ovn] [networking-sfc] SFC and OVN > > Ryan, > > Agree with your description of the problem. The only thing I would > add is that in the case of bi-directional chains the return flows > need to go through the same VNF(Port-pair). I'm pretty sure that is caught automagically, isn't it? Ryan > > Regards > > John > > From: Ryan Moats <rmo...@us.ibm.com> > Date: Wednesday, May 25, 2016 at 9:29 PM > To: Ben Pfaff <b...@ovn.org> > Cc: "discuss@openvswitch.org" <discuss@openvswitch.org>, John McDowall < > jmcdow...@paloaltonetworks.com>, Justin Pettit <jpet...@ovn.org>, > OpenStack Development Mailing List <openstack-...@lists.openstack.org > >, Russell Bryant <russ...@ovn.org> > Subject: Re: [OVN] [networking-ovn] [networking-sfc] SFC and OVN > > Ben Pfaff <b...@ovn.org> wrote on 05/25/2016 07:44:43 PM: > > > From: Ben Pfaff <b...@ovn.org> > > To: Ryan Moats/Omaha/IBM@IBMUS > > Cc: John McDowall <jmcdow...@paloaltonetworks.com>, > > "discuss@openvswitch.org" <discuss@openvswitch.org>, OpenStack > > Development Mailing List <openstack-...@lists.openstack.org>, Justin > > Pettit <jpet...@ovn.org>, Russell Bryant <russ...@ovn.org> > > Date: 05/25/2016 07:44 PM > > Subject: Re: [OVN] [networking-ovn] [networking-sfc] SFC and OVN > > > > On Wed, May 25, 2016 at 09:27:31AM -0500, Ryan Moats wrote: > > > As I understand it, Table 0 identifies the logical port and logical > > > flow. I'm worried that this means we'll end up with separate bucket > > > rules for each ingress port of the port pairs that make up a port > > > group, leading to a cardinality product in the number of rules. > > > I'm trying to think of a way where Table 0 could identify the packet > > > as being part of a particular port group, and then I'd only need one > > > set of bucket rules to figure out the egress side. However, the > > > amount of free metadata space is limited and so before we go down > > > this path, I'm going to pull Justin, Ben and Russell in to see if > > > they buy into this idea or if they can think of an alternative. > > > > I've barely been following the discussion, so a recap of the question > > here would help a lot. > > > > Sure (and John gets to correct me where I'm wrong) - the SFC proposal > is to carry a chain as a ordered set of port groups, where each group > consists of multiple port pairs. Each port pair consists of an ingress > port and an egress port, so that traffic is load balanced between > the ingress ports of a group. Traffic from the egress port of a group > is sent to the ingress port of the next group (ingress and egress here > are from the point of view of the thing getting the traffic). > > I was suggesting to John that from the view of the switch, this would > be reversed in the openvswitch rules - the proposed CHAINING stage > in the ingress pipeline would apply the classifier for traffic entering > a chain and identify traffic coming from an egress SFC port in the > midst of a chain. The egress pipeline would identify the next ingress SFC > port that gets the traffic or the final destination for traffic exiting > the chain. > > Further, I pointed him at the select group for how traffic could be > load balanced between the different ports that are contained in a port > group, but that I was worried that I'd need a cartesian product of rules > in the egress chain stage. Having thought about this some more, I'm > realizing that I'm confused and the number of rules should not be that > bad: > > - Table 0 will identify the logical port the traffic comes from > - The CHAINING stage of the ingress pipeline can map that logical > port information to the port group the port is part of. > - The CHAINING stage of the egress pipeline would use that port > group information to select the next logical port via a select group. > > I believe this requires a total number of rules in the CHAINING stages > of the order of the number of ports in the service chain. > > The above is predicated on carrying the port group information from > the ingress pipeline to the egress pipeline in metadata, so I would > be looking to you for ideas on where this data could be carried, since > I know that we don't have infinite space for said metadata... > > Ryan
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