> > 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 > > > > ---------------------------------------------------- > > > > > > > > > > > > _______________________________________________ > > > > nvo3 mailing list > > > > [email protected] > > > > https://www.ietf.org/mailman/listinfo/nvo3 > > > > > > _______________________________________________ > > nvo3 mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/nvo3 > > _______________________________________________ > > nvo3 mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/nvo3 > > _______________________________________________ > > nvo3 mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/nvo3 > > _______________________________________________ > > nvo3 mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/nvo3 > > _______________________________________________ > > nvo3 mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/nvo3 > _______________________________________________ > nvo3 mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/nvo3 _______________________________________________ nvo3 mailing list [email protected] https://www.ietf.org/mailman/listinfo/nvo3
