Subject: Re: [nvo3] Virtual Network - what's an instance?

From: Thomas Narten <[email-masked]>
Date: Mon, 01 Jul 2013 14:35:07 -0400

Lucy,

> So this is because that the problem statement already uses it for
> different meaning.

Yes, but it is also because we are talking about two different things,
and using the same terminology for different things tends to be
confusing.  IMO, there are times when referring to each of those
different things is important, so being able to distinguish them is
necessary.

While I could change the problem statement to not use instance this
way, I hesitate at doing so. IMO, "instance" is an intuitive and
natural way to refer to a specific virtual network. And the term
"instance" is well known/used to refer to specific instantiations of a
an abstract term. This is just normal english.

> Should the framework draft support the consistency to L2VPN/L3VPN or
> the nvo3 problem statement?  L2/L3VPN documents were generated much
> early without the description issues.

I looked at the L3VPN framework (RFC4176). it does use similar
terminology:

>    VPN Instance:
> 
>       From a management standpoint, a VPN instance is the collection of
>       configuration information associated with a specific VPN, residing
>       on a PE router.

Oddly enough, however, it defines the term and then doesn't actually
use it anywhere else in the document! The term "Instance" is used
exactly one time in the document, i.e., in the defintion. :-( Thus, I
hardly see this as a compelling precedent.

Looking at the L2VPN framework (RFC 4664), it seems to use "instance"
more like the problem statement does. E.g, I find wording like:

>    A "VPLS instance" consists of a set of VPLS Forwarders (no more than
>    one per PE) connected by pseudowires.

or

>    Two CEs are connected to the same virtual backbone if and only if
>    they are members of the same VPLS instance (i.e., same VPN).

or

>    As Figure 3 indicates,
>    if a set of PEs support a common VPLS instance, then there is an
>    Emulated LAN, corresponding to that VPLS instance, to which each of
>    those PE bridges attaches (via an emulated interface).

I do not see "instance" used to refer only to the state on (say) a
local PE.

Thomas

---

From: Lucy yong <[email-masked]>
Date: Mon, 1 Jul 2013 19:41:05 +0000

Hi Tom,

IMO: if VSI, VFI, VRI, EVI terms have been used for long time to model the entities on PE and if we are doing the similar thing in the nvo3 framework, it should be fine to use  VNI in the model. It should be requested to change because the problem statement uses the description of the virtual network instance. We can still use the word "instance" in the problem statement draft. To avoid the confusion, just state "an instance of virtual network" as Larry suggests. We can easily address this conflict.

Regards,
Lucy 

> -----Original Message-----
> From: Thomas Narten [mailto:[email-masked]]
> Sent: Monday, July 01, 2013 1:35 PM
> To: Lucy yong
> Cc: [email-masked]
> Subject: Re: [nvo3] Virtual Network - what's an instance?
> 
> Lucy,
>

---

From: Eric Gray <[email-masked]>
Date: Tue, 2 Jul 2013 10:16:28 +0000

Lucy,

	In my opinion, there are no conflicts.  Folks that have indicated that there is
confusion have done so largely based on the various threads related to an initial set
of questions about terminology, and have gone back and forth without any specific 
references to points in drafts where there is a question about what the phrases or
terms mean, or with example text completely removed from context.

	If there is confusion, right now, it is entirely a result of the amount of noise.

--
Eric

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Lucy yong
Sent: Monday, July 01, 2013 3:41 PM
To: Thomas Narten
Cc: [email-masked]
Subject: Re: [nvo3] Virtual Network - what's an instance?

Hi Tom,

Regards,
Lucy 

> I do not see "instance" used to refer only to the state on (say) a 

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