David,
I do not disagree. My earlier comments were based on Marc's
"extracted" definition for VNI - which is what everyone else was also
responding to.
The full definition in the current posted Framework draft is:
"VNI: Virtual Network Instance. This is one instance of a virtual
overlay network. It refers to the state maintained for a given VN on
a given NVE. Two Virtual Networks are isolated from one another and
may use overlapping addresses."
You mentioned this earlier in this thread (though that part of
the thread is now pretty hard to read).
I strongly suspect that the extra detail in the full definition may
have assuaged some concerns raised in the discussion about the way
we defined it - since it clearly says more than Marc's extracted version
below.
However, I'm unsure how the detailed version is inconsistent
with the way we used the phrase in the problem statement draft. It
is perhaps somewhat more specific to a host operating system (in the
reference to VN state maintained in an NVE) - but the meaning seems
to be the same.
It is simply a more detailed way of saying what Marc said below
- i.e. - it is "[a] specific instance of a VN ."
Also, from what Marc said, I assume that the definition that is
present in the "soon to be published version" is significantly briefer
than the definition in the currently posted version.
This seems to indicate that the definition is no longer the one
that you referred to earlier and seem to be referring to now.
Perhaps we are confusing things by referring to the posted
version, after having been told that the current up-to-date draft has
a different definition?
That being the case, it seems that the definition in the "soon
to be published version" is in alignment with the way that we use the
phrase in the problem statement draft.
--
Eric
-----Original Message-----
From: Black, David [mailto:[email protected]]
Sent: Thursday, June 27, 2013 8:43 PM
To: Eric Gray; [email protected]
Subject: RE: Virtual Network - what's an instance?
Importance: High
Eric,
> The problem statement draft does not use the term VNI, at all.
>
> I was surprised to hear you say this, so I checked. :-)
>
> The PS draft does use the phrase "virtual network instance" (a
> lot) -
Well, the framework draft's definition of VNI starts with:
VNI: Virtual Network Instance.
and continues with a definition that does not match the problem statement
draft's usage of "virtual network instance" that is described in your message.
I would think that "Virtual Network Instance" (framework draft) and "virtual
network instance" (problem statement draft) ought to be the same term - do you
disagree?
Thanks,
--David
> -----Original Message-----
> From: Eric Gray [mailto:[email protected]]
> Sent: Thursday, June 27, 2013 4:19 PM
> To: Black, David; Reith, Lothar; [email protected]
> Subject: RE: Virtual Network - what's an instance?
>
> David,
>
> The problem statement draft does not use the term VNI, at all.
>
> I was surprised to hear you say this, so I checked. :-)
>
> The PS draft does use the phrase "virtual network instance" (a
> lot) - but it uses the term in the sense of distinguishing the concept
> of a "virtual network" from a specific virtual network (in fact, the
> words "each", "specific", "particular", "different" and/or
> "individual" are frequently - if not consistently
> - used with the phrase).
>
> There are some cases where the phrase "virtual network instance"
> could arguably have been replaced with "virtual network" - but that
> would very likely have provoked argument in return.
>
> --
> Eric
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf
> Of Black, David
> Sent: Saturday, June 22, 2013 3:28 PM
> To: Reith, Lothar; [email protected]
> Cc: Black, David
> Subject: Re: [nvo3] Virtual Network - what's an instance?
>
> > > Can someone please come up with a UML cardinality diagram, which
> > > explains the relation between VN, VNI, and CUG?
>
> Please don't :-). Here's my 0.02 ... :
>
> a) VN and VNI (spelled out) are used interchangeably in the problem
> statement draft. I think it's a bad idea to split hairs to try to
> distinguish those terms, and I definitely don't want to rewrite the
> problem statement draft to make that distinction.
>
> b) CUG appears to be a term from BGP/MPLS L3VPN space that should be
> used only with such L3VPNs, not more generally. NVO3 has settled on
> VN as the basic solution-independent concept, and I think CUG only
> adds confusion (e.g., as demonstrated by Lothar's message). Let's stick with
> VN.
>
> c) The Framework draft needs a new term to identify the portion of a
> VN that exists in an NVE, as VNI should not be used for that purpose - see a)
> above.
> That new term is not VAP, because VAP is a port abstraction, not a
> network abstraction, and we need a port abstraction to identify the
> entity to which TS's are connected (i.e., a TS is connected to a VAP,
> possibly multiple VAPs).
>
> In private email, I've suggested VNLI (Virtual Network Local Instance)
> for c)
> - while I'm not strongly attached to the term, I like the use of the
> word "local" to make it clear that this term designates a subset of a
> VN, and is specific to an NVE.
>
> Thanks,
> --David
>
> > -----Original Message-----
> > From: [email protected] [mailto:[email protected]] On Behalf
> > Of Linda Dunbar
> > Sent: Friday, June 21, 2013 10:16 PM
> > To: Reith, Lothar; Joe Pelissier (jopeliss); [email protected]
> > Subject: Re: [nvo3] Virtual Network - what's an instance?
> >
> > My 2 cents:
> >
> > One virtual network may have multiple IDs.
> >
> > Linda
> >
> > > -----Original Message-----
> > > From: [email protected] [mailto:[email protected]] On
> > > Behalf Of Reith, Lothar
> > > Sent: Friday, June 21, 2013 7:39 AM
> > > To: Joe Pelissier (jopeliss); [email protected]
> > > Subject: Re: [nvo3] Virtual Network - what's an instance?
> > >
> > > My 2 cents:
> > >
> > > For a network centric engineer, there may not be a difference
> > > between a virtual network and a virtual network instance.
> > >
> > > For a compute centric engineer (such as those creating the virtual
> > > networks via a Quantum API in OpenStack), there may very well be a
> > > fundamental difference as he may associate with " virtual network"
> > > a class, and with "virtual network instance" an object.
> > >
> > > One key problem in IETF is, that key terms often may be loosely defined.
> > > I am afraid, that this may be just happening again (similar and
> > > related also with the term CUG).
> > >
> > > Can someone please come up with a UML cardinality diagram, which
> > > explains the relation between VN, VNI, and CUG?
> > >
> > > Or tell us their view regarding which of the following statements
> > > are
> > > true:
> > >
> > > 1. There is always a one to one relation between VN and VNI
> > > (therefore the terms are actually synonymous and can be harmonized
> > > to VN) 2. There is always a 1 to n relation between VN and VNI
> > > (like between Class and object) 3. There is always a one to one
> > > relation between a VN and a CUG 4. There may be a 1:n relation
> > > between CUG and VN, i.e. the members of one CUG may be network
> > > endpoints (devices/stations/station
> > > interfaces/NICs/vNICs) in multiple VNs (or VNIs?) 5. There may be
> > > a 1:n relation between VN and CUG, i.e. a VN may have network
> > > endpoints which are members of multiple CUGs 6. There may be an
> > > n:m relation between CUG and VN, because both 4 and
> > > 5 are true statements.
> > >
> > > Lothar
> > >
> > >
> > >
> > >
> > > -----Ursprüngliche Nachricht-----
> > > Von: [email protected] [mailto:[email protected]] Im
> > > Auftrag von Joe Pelissier (jopeliss)
> > > Gesendet: Donnerstag, 20. Juni 2013 20:00
> > > An: [email protected]
> > > Betreff: Re: [nvo3] Virtual Network - what's an instance?
> > >
> > > Ok, that seems to make sense, but in this case, VN Instance does
> > > not need to be a defined term. I.e., VN is defined, and
> > > "instance" has its normal English meaning. So maybe keep the
> > > definition of "Virtual Network", delete the definition for
> > > "Virtual Network Instance", and in the text use "Virtual Network
> > > instance" instead of "Virtual Network Instance".
> > >
> > > Still, I doubt that there is any place that the term "Virtual
> > > Network Instance" is used that could not be replaced with "Virtual
> Network"
> > > since the singular form of VN is, by definition, an instance.
> > > Adding the extra word "instance" may make the intent more clear in
> > > some cases; after all, we are network engineers, so we are always
> > > promoting redundancy :-).
> > >
> > > Cheers,
> > > Joe Pelissier
> > >
> > >
> > > -----Original Message-----
> > > From: Dave Hood [mailto:[email protected]]
> > > Sent: Thursday, June 20, 2013 6:00 AM
> > > To: Joe Pelissier (jopeliss); [email protected]
> > > Subject: RE: Virtual Network - what's an instance?
> > >
> > > Right.
> > >
> > > The point is that, to the client, the idea of instance is
> > > irrelevant because there is only one.
> > >
> > > On the other hand, the server instantiates a separate VN for each
> > > client, a total of zero or more, depending on the number of
> > > clients, so VN instances are an essential concept to the server.
> > >
> > > Dave
> > >
> > > -----Original Message-----
> > > From: [email protected] [mailto:[email protected]] On
> > > Behalf Of Joe Pelissier (jopeliss)
> > > Sent: Wednesday, June 19, 2013 7:55 PM
> > > To: [email protected]
> > > Subject: Re: [nvo3] Virtual Network - what's an instance?
> > >
> > > Hi Dave,
> > > Maybe I could rephrase your last sentence:
> > > "....From the server's point of view, there are as many VNs as
> > > there are clients."
> > > This appears to have the same meaning as your sentence, which
> > > seems to indicate the terms are synonymous.
> > >
> > > Cheers,
> > > Joe
> > >
> > > -----Original Message-----
> > > From: Dave Hood [mailto:[email protected]]
> > > Sent: Wednesday, June 19, 2013 4:03 PM
> > > To: Joe Pelissier (jopeliss); [email protected]
> > > Subject: RE: Virtual Network - what's an instance?
> > >
> > > IMO, a virtual network is the set of [network] resources exposed
> > > by a server to a client. From the client's point of view, there is
> > > only one VN. From the server's point of view, there are as many
> > > VNIs as there are clients.
> > >
> > > Would that be a useful way to describe the difference?
> > >
> > > Dave
> > >
> > > -----Original Message-----
> > > From: [email protected] [mailto:[email protected]] On
> > > Behalf Of Joe Pelissier (jopeliss)
> > > Sent: Wednesday, June 19, 2013 3:29 PM
> > > To: [email protected]
> > > Subject: Re: [nvo3] Virtual Network - what's an instance?
> > >
> > > Maybe it's just me, but the definition of VNI does not seem useful:
> > >
> > > "Virtual Network Instance (VNI): A specific instance of a VN."
> > > If someone did not understand what a Virtual Network Instance is,
> > > then simply adding the word "specific" does not help much.
> > > Essentially, a VNI is a VN - the terms appear synonymous, so it
> > > would be best to simply eliminate the VNI term.
> > >
> > > My $0.02 worth...
> > > Joe Pelissier
> > >
> > > -----Original Message-----
> > > From: [email protected] [mailto:[email protected]] On
> > > Behalf Of Black, David
> > > Sent: Wednesday, June 19, 2013 7:48 AM
> > > To: LASSERRE, MARC (MARC)
> > > Cc: [email protected]
> > > Subject: Re: [nvo3] Virtual Network - what's an instance?
> > >
> > > Marc,
> > >
> > > Good - that'll work well, and I'm assuming that you'll bring the
> > > rest of the draft into line, as there is usage of the VNI acronym
> > > to refer to the NVE-local portion of a VN (what I refer to as VNLI below).
> > >
> > > Thanks,
> > > --David
> > >
> > > > -----Original Message-----
> > > > From: LASSERRE, MARC (MARC)
> > > > [mailto:[email protected]]
> > > > Sent: Wednesday, June 19, 2013 3:54 AM
> > > > To: Black, David
> > > > Cc: [email protected]
> > > > Subject: RE: Virtual Network - what's an instance?
> > > >
> > > > Hi David,
> > > >
> > > > In the soon-to-be-published revision of the framework draft, the
> > > > VN & VNI definitions stand as:
> > > >
> > > > Virtual Network (VN): A VN is a logical abstraction of a
> > > > physical network that provides L2 or L3 network services to a
> > > > set of Tenant Systems. A VN is also known as a Closed User Group (CUG).
> > > >
> > > > Virtual Network Instance (VNI): A specific instance of a VN.
> > > >
> > > > I think that this addresses your concern.
> > > >
> > > > Marc
> > > >
> > > > > -----Original Message-----
> > > > > From: [email protected] [mailto:[email protected]] On
> > > Behalf
> > > > > Of Black, David
> > > > > Sent: Wednesday, June 19, 2013 1:24 AM
> > > > > To: [email protected]
> > > > > Subject: [nvo3] Virtual Network - what's an instance?
> > > > >
> > > > > In working on some control plane draft material, I've run
> > > > > across an inconsistency in the use of the concept of a
> > > > > "virtual network instance"
> > > > > (or VNI) between the problem statement and framework drafts.
> > > > >
> > > > > The problem statement draft does not define "virtual network
> > > instance"
> > > > > and uses that term more or less interchangeably with "virtual
> > > network"
> > > > > to refer to a specific virtual network. Here's an example
> > > > > with
> > > both
> > > > > terms used in the same sentence near the top of p.5:
> > > > >
> > > > > A key requirement is that each
> > > > > individual virtual network instance be isolated from other
> > > virtual
> > > > > network instances, with traffic crossing from one virtual
> > > network
> > > > > to
> > > > > another only when allowed by policy.
> > > > >
> > > > > The framework draft defines Virtual Network Instance (VNI) as
> > > > > effectively being the portion of a virtual network that is
> > > > > instantiated in an NVE:
> > > > >
> > > > > VNI: Virtual Network Instance. This is one instance of
> > > > > a virtual
> > > > > overlay network. It refers to the state maintained for
> > > > > a given VN on
> > > > > a given NVE. Two Virtual Networks are isolated from one
> > > > > another and
> > > > > may use overlapping addresses.
> > > > >
> > > > > Something's wrong here. Back in February, Thomas Narten
> > > > > proposed that we use the problem statement terminology
> > > > > consistently in the framework draft, but there hasn't been any
> > > > > further
> discussion.
> > > > >
> > > > > Speaking for myself, the problem statement draft's usage seems
> > > > > more intuitive (an "instance" of a virtual network is a
> > > > > virtual network, not part of one, as is the case in the
> > > > > framework draft), but we've had the VNI acronym around in the
> > > > > framework draft for a good long time now.
> > > > >
> > > > > If it were ok to change the framework draft, I would prefer:
> > > > >
> > > > > VNLI: Virtual Network Local Instance. This is an
> > > > > instance
> > > of a
> > > > > virtual overlay network on a specific NVE. The VNLI
> > > > > refers to
> > > the
> > > > > local state and associated processing for a given VN on
> > > > > a
> > > given
> > > > > NVE. Within an NVE, VNLIs are isolated from one another and
> > > > > may use overlapping network addresses.
> > > > >
> > > > > But that's just my 0.02 - what should be done about this?
> > > > >
> > > > > Thanks,
> > > > > --David
> > > > > ----------------------------------------------------
> > > > > David L. Black, Distinguished Engineer EMC Corporation, 176
> > > > > South St., Hopkinton, MA 01748
> > > > > +1 (508) 293-7953 FAX: +1 (508) 293-7786
> > > > > [email protected] Mobile: +1 (978) 394-7754
> > > > > ----------------------------------------------------
> > > > >
> > > > >
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