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
