[sfc-dev] NIC & SFC interaction

Mentze, Duane duane.mentze at hp.com
Mon Mar 2 19:01:10 UTC 2015

Hi Abhijit,

Thanks for reaching out to the nic team and raising NIC and SFC interaction questions.

Would it be possible to schedule an online meeting to discuss nic-sfc interactions and the multi-app slide?

Also here are my responses to your questions:

-slide 40 is an overview slide and it  mostly shows blocks – many arrows are not shown
-the slides show SFC returning service function paths (SFP)
  -in general SFC needs to return enough information to the PPE (portable policy engine) so the CodeGeneration can realize the SFP
-the mapping from an SFP to an exact path through the network happens in PPE/CodeGen

Please let me know if you want to schedule a time for an online discussion.



From: Abhijit Kumbhare <abhijitkoss at gmail.com<mailto:abhijitkoss at gmail.com>>
Date: Thursday, February 26, 2015 at 7:18 PM
To: "nic-dev at lists.opendaylight.org<mailto:nic-dev at lists.opendaylight.org>" <nic-dev at lists.opendaylight.org<mailto:nic-dev at lists.opendaylight.org>>
Cc: "sfc-dev at lists.opendaylight.org<mailto:sfc-dev at lists.opendaylight.org>" <sfc-dev at lists.opendaylight.org<mailto:sfc-dev at lists.opendaylight.org>>, "GroupBasedPolicy-dev at lists.opendaylight.org<mailto:GroupBasedPolicy-dev at lists.opendaylight.org>" <groupbasedpolicy-dev at lists.opendaylight.org<mailto:groupbasedpolicy-dev at lists.opendaylight.org>>
Subject: [sfc-dev] NIC & SFC interaction

Hi Duane,

I am looking at  https://wiki.opendaylight.org/images/6/68/Multiple.application.support.pptx - the architecture overview diagram on slide 27. You have a single arrow going from Portable Policy Engine to SFC called "chain request". Looking at the SFC slides (starting with slide 40) - I believe you need to have an arrow going back to the Policy Engine as "return chains" to make things clear (there were folks confused when I relayed your material):

  1.  On slide 47 the policy engine makes service chain requests to the SFC module
  2.  On slide 48, the SFC queries the endpoint database to resolve SFC specifications (find “firewall", find “IPS” - or rather find endpoint from the endpoint database with attribute “firewall” or “IPS")
  3.  On slide 49, SFC returns the service function chains (shown here to be in the form of a list of IP addresses of the SFs) to the policy engine.
  4.  On slide 50, the policy engine calls the code generator to generate the OpenFlow rules for the SFCs 1, 2 and 3 (this should be SFPs 1, 2 and 3)

I believe you are returning the rendered service function paths (rendered SFPs) back to the policy engine so that you do not have a multi writer problem (as opposed to having SFC also writing the rules for the service function paths to the devices in addition to the "Code Generation" pluggable southbound).

BTW, I don't think the existing SFC-GBP integration PoC does it this way (only returning the rendered SFPs back to GBP). As per https://wiki.opendaylight.org/view/Service_Function_Chaining:Group_Based_Policy_Integration#Programming_of_Southbound_Devices,  SFC will be programming the OVS via REST API (they are avoiding conflicts as GBP programs the OpenFlow rules as well as the classifier). So my question is do you expect SFC project to implement a different API (only returning the rendered SFPs - no programming the SFFs)? Or do you want to ask SFC project to change their implementation while it is still being worked on (to only return the rendered SFPs - no programming the SFFs)?


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