The question regarding FCoE is whether overlay solutions need to transport
it.  I think the answer is no.  If something operates at the underlay level
than it isn't in scope for NVo3, including DCB.


On Tuesday, August 28, 2012, Somesh Gupta wrote:

>
>
> > -----Original Message-----
> > From: [email protected] <javascript:;> 
> > [mailto:[email protected]<javascript:;>]
> On Behalf Of
> > Ivan Pepelnjak
> > Sent: Tuesday, August 28, 2012 12:22 AM
> > To: Stiliadis, Dimitrios (Dimitri)
> > Cc: Black, David; [email protected] <javascript:;>; Linda Dunbar
> > Subject: Re: [nvo3] Let's refocus on real world (was: Comments on Live
> > Migration and VLAN-IDs)
> >
> > Dimitri,
> >
> > We're more in agreement than it might seem. I might have my doubts
> > about
> > the operational viability of the OpenStack-to-baremetal use case you
> > described below, but I'm positive someone will try to do that as well.
> >
> > In any case, regardless of whether we're considering VMs or bare-metal
> > servers, in the simplest scenario the server-to-NVE connection is a
> > point-to-point link, usually without VLAN tagging.
> >
> > In the VM/hypervisor case, NVE is implemented in the hypervisor soft
> > switch; in the baremetal server case, it has to be implemented in the
> > ToR switch.
>
>   This is certainly only today's restriction. If nov3 takes off, there
>   certainly could be a pseudo-driver in Linux that could implement the
>   NVE (like a VLAN driver) without much additional overhead.
>
> >
> > It's important to keep in mind the limitations of the ToR switches to
> > ensure whatever solution we agree upon will be implementable in ToR
> > switches as well, but it makes absolutely no sense to assume NVE will
> > not be in the hypervisor (because someone wants to support a customer
> > having a decade-old VLAN-only hypervisor soft switch).
> >
> > As for ToR switch capabilities, Dell has demonstrated NVGRE support and
> > Arista is right now showing off a hardware VXLAN VTEP prototype, so I
> > guess it's safe to assume next-generation merchant silicon will support
> > GRE- and UDP-based encapsulations well before we'll agree on what NVO3
> > solution should be.
> >
> > Finally, can at least some of us agree that the topology that makes
> > most
> > sense is a direct P2P link between (VM or bare-metal) server and NVE
> > using VLAN tagging only when a server participating in multiple L2 CUGs
> > has interface limitations?
> >
> > Kind regards,
> > Ivan
> >
> > On 8/27/12 6:55 AM, Stiliadis, Dimitrios (Dimitri) wrote:
> > > Ivan:
> > >
> > > I agree and at the same time disagree with some of the statements
> > > below. I would like to understand your view.
> > >
> > > See inline:
> > >
> > > On 8/25/12 8:22 AM, "Ivan Pepelnjak"<[email protected]>  wrote:
> > >
> > >> On 8/24/12 11:11 PM, Linda Dunbar wrote:
> > >> [...]
> > >>
> > >>> But most, if not all, data centers today don't have the Hypervisors
> > >>> which can encapsulate the NVo3 defined header. The deployment to
> > all
> > >>> 100% NVo3 header based servers won't happen overnight. One thing
> > for
> > >>> sure that you will see data centers with mixed types of servers for
> > >>> very long time.
> > >>>
> > >>> If NVEs are in the ToR, you will see mixed scenario of blade
> > servers,
> > >>> servers with simple virtual switches, or even IEEE802.1Qbg's VEPA.
> > So
> > >>> it is necessary for NVo3 to deal with the "L2 Site" defined in this
> > >>> draft.
> > >>
> > >> There are two hypothetical ways of implementing NVO3: existing
> > layer-2
> > >> technologies (with well-known scaling properties that prompted the
> > >> creation of NVO3 working group) or something-over-IP encapsulation.
> > >>
> > >> I might be myopic, but from what I see most data centers today (at
> > least
> > >> based on market shares of individual vendors) don't have ToR
> > switches
> > >> that would be able to encapsulate MAC frames or IP datagrams in UDP,
> > GRE
> > >> or MPLS envelopes. I am not familiar enough with the commonly used
> > >> merchant silicon hardware to understand whether that's a software or
> > >> hardware limitation. In any case, I wouldn't expect switch vendors
> > to
> > >> roll out NVO3-like something-over-IP solutions any time soon.
> > >>
> > >> On the hypervisor front, VXLAN is shipping for months, NVGRE is
> > included
> > >> in the next version of Hyper-V and MAC-over-GRE is available (with
> > Open
> > >> vSwitch) for both KVM and Xen. Open vSwitch is also part of standard
> > >> Linux kernel distribution and thus available to any other Linux-
> > based
> > >> hypervisor product.
> > >>
> > >> So: all major hypervisors have MAC-over-IP solutions, each one using
> > a
> > >> proprietary encapsulation because there's no standard way of doing
> > it,
> > >> and yet we're spending time discussing and documenting the history
> > of
> > >> evolution of virtual networking. Maybe we should be a bit more
> > >> forward-looking, acknowledge the world has changed, and come up with
> > a
> > >> relevant hypervisor-based solution.
> > >
> > > Correct, and here is where IETF as a standard body fails. There is no
> > > easy way (any time soon) for a VXLAN based solution to talk to an
> > NVGRE
> > > or MAC/GRE, or Cloudstack MAC/GRE or STT  (you forgot this one),
> > based
> > > solution.
> > > Proprietary approaches that drive enterprises to vendor lock ins. And
> > > instead
> > > of trying to address the first problem that is about
> > "interoperability",
>
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