[ovs-discuss] [openstack-dev] [OVN] [networking-ovn] [networking-sfc] SFC andOVN

[Na Zhu]

Ryan,

Thanks your really helpful comments.
If the lswitch is determined by flow classifier, I think no need to record 
in logical router, ovn creates patch port pair for router interface, one 
patch port connects logical switch, the other connects logical router. The 
one connects logical switch is neutron router interface. We still can 
record port chain on logical switch for the logical-source-port is router 
interface, right?



Regards,
Juno Zhu
IBM China Development Labs (CDL) Cloud IaaS Lab
Email: nazhu at cn.ibm.com
5F, Building 10, 399 Keyuan Road, Zhangjiang Hi-Tech Park, Pudong New 
District, Shanghai, China (201203)



From:   Ryan Moats/Omaha/IBM
To:     John McDowall <jmcdowall at paloaltonetworks.com>
Cc:     Na Zhu <nazhu at cn.ibm.com>, Srilatha Tangirala/San 
Francisco/IBM at IBMUS, "OpenStack Development Mailing List \(not for usage 
questions\)" <openstack-dev at lists.openstack.org>, discuss 
<discuss at openvswitch.org>
Date:   2016/06/15 12:42
Subject:        Re: [ovs-discuss] [openstack-dev] [OVN] [networking-ovn] 
[networking-sfc] SFC andOVN


"discuss" <discuss-bounces at openvswitch.org> wrote on 06/14/2016 10:31:40 
PM:

> From: John McDowall <jmcdowall at paloaltonetworks.com>
> To: Na Zhu <nazhu at cn.ibm.com>
> Cc: Srilatha Tangirala/San Francisco/IBM at IBMUS, "OpenStack 
> Development Mailing List \(not for usage questions\)" <openstack-
> dev at lists.openstack.org>, discuss <discuss at openvswitch.org>
> Date: 06/14/2016 10:48 PM
> Subject: Re: [ovs-discuss] [openstack-dev] [OVN] [networking-ovn] 
> [networking-sfc] SFC andOVN
> Sent by: "discuss" <discuss-bounces at openvswitch.org>
> 
> Juno,
> 
> It is a container for port-pair-groups and flow-classifier. I 
> imagine there could be more the than one port-chain per switch. Also
> we may want to extend the model beyond a single lswitch 

I agree that there could be more than one port-chain per switch, 
determined
by the flow classifier. 

What I'm confused by is:

1. Why are items only recorded in logical switches?  I would think
that I could also attach an SFC to a logical router - although I admit
that the current neutron model for ports doesn't really allow that
easily.  Couple that with the change of name from Logical_Port to
Logical_Switch_Port, and I'm left wondering if we aren't better off
with the following "weak" links instead: 
-the Port_Chain includes the logical switch as an external_id
-each Port_Pair_Group includes the Port_Chain as an external_id
-each Port_Pair includes the PPG as an external_id
-each Logical_Switch_Port includes the PP as an external_id

I *think* that *might* allow me (in the future) to attach a port chain
to a logical router by setting the logical router as an external_id and
using Logical_Router_Ports to make up the PPs...


2. I still don't see what Logical_Flow_Classifier is buying me that
ACL doesn't - I can codify all of the classifiers given in the match
criteria of an ACL entry and codify the first PPG of the SFC as
the action of the ACL entry...

Ryan


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