[sfc-dev] [SFC] Why doesn't OpenDaylight use Ether/NSH encapsulation?

Keith Burns alagalah at gmail.com
Tue Aug 18 21:40:27 UTC 2015


If the SFF / classifiers are outside the OVS then the OVS in that instance
is just underlay.

In that case NSH support is largely irrelevant for OVS as underlay.
On Aug 18, 2015 11:54 AM, "Dave Dolson" <ddolson at sandvine.com> wrote:

> I’m saying that the classifiers and SFFs could be external to the
> switching layer.
>
> For packets leaving a host, choose the destination MAC address before
> submitting the packet to the switch.
>
>
>
> Is it the case that OVS provides a convenient module because it already
> has the control-plane interfaces?
>
>
>
>
>
> *From:* Keith Burns [mailto:alagalah at gmail.com]
> *Sent:* Tuesday, August 18, 2015 2:45 PM
> *To:* Dave Dolson
> *Cc:* opendaylight sfc
> *Subject:* Re: [sfc-dev] [SFC] Why doesn't OpenDaylight use Ether/NSH
> encapsulation?
>
>
>
> Dave,
>
> The purpose of the OVS classifier (GBP) and OVS SFF (SFC) is to ensure
> packets get to the right SF based on NSH fields.
>
> If OVS can't MATCH/ACTION on these fields, it can't do those functions.
>
> Matching and acting on ethertype would only let us fwd to an (in fact
> potentially all) connected external classifier or SFF which would have to
> have NSH visibility.
>
> On Aug 18, 2015 11:26 AM, "Dave Dolson" <ddolson at sandvine.com> wrote:
>
>
>
> The current approach to SFC in OpenDaylight seems to require a new Open
> vSwitch, but it should be possible to have NSH without any changes to OVS.
>
> Here’s my reasoning:
>
>
>
> The encapsulation of NSH directly in Ethernet, (or in Ethernet/VLAN) is
> defined in the NSH draft:
> https://tools.ietf.org/html/draft-ietf-sfc-nsh-01#section-9.3
>
> (Ethertype 0x894F)
>
>
>
> So any old switch or virtual LAN segment can deliver these packets between
> Ethernet end-points.
>
>
>
> Why not go with that? Keep NSH out of the switching and keep the NSH
> processing only in the machines, virtual or otherwise.
>
> Why is it believed that VxLAN orchestration must be involved with NSH?
>
>
>
> (I realize of course that some packets may be carried over VxLAN networks,
> but that should be transparent to protocols riding as Ethernet payload.)
>
>
>
>
>
> David Dolson
>
> Senior Software Architect, Sandvine Inc.
>
>
>
>
> _______________________________________________
> sfc-dev mailing list
> sfc-dev at lists.opendaylight.org
> https://lists.opendaylight.org/mailman/listinfo/sfc-dev
>
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