(resending from my correct mailto email with minor edits)

Hi David,

I am also of the opinion that the we don't want to single a VNI to support both 
L2 and L3 service.  

The VNIF (VNI interconnecting InterFace) described in Lucy's draft-mity 
use-cases is used to interconnect an L2VNI with an L3VNI within the same NVE, 
similar to how an IRB logical interface would be used to connect a routing 
instance with a bridge instance on a routing switch (as you already seem to be 
intimately familiar with).  Here the L2VNI would be a member of L2VNs and the 
L3VNI a member of L3VNs.  My concern was that the framework draft doesn't seem 
capture the "VNIF" entity.  Are basic interworking entities such as VNIF not in 
scope?

Best -- aldrin


On Jun 26, 2012, at 9:51 AM, <[email protected]> <[email protected]> wrote:

> Hi Aldrin,
>  
> I observe that for IRB to work on a VNI, the VNI has to provide layer 2 
> service.  What
> I mean by this is that IRB assumes that the Ethernet header is present on all 
> traffic -
> bridging uses that Ethernet header, whereas the routing portion of IRB 
> (logically)
> strips the Ethernet header and operates on the IP header.  To apply IRB to 
> nvo3 traffic,
> the inner headers (Ethernet and IP) are involved after decapsulation (again, 
> logically).
>  
> The reason for “(logically)” is that there are optimization possibilities 
> when the
> same headers will be present outbound (e.g., when routing between two VNIs 
> that use
> the same encapsulation, an integrated implementation may modify the headers 
> in place
> - as long as the outbound traffic is correctly formatted, it doesn’t matter 
> whether
> the headers were stripped and reapplied internally vs. modified in place).
>  
> In order to mix layer 2 service (inner Ethernet header present) and layer 3 
> service
> (no inner Ethernet header present) on the same VNI, the encapsulation needs 
> to indicate
> whether the first header after the encapsulation header is Ethernet or IP.  
> Obviously,
> there are ways to do that (GRE comes to mind), but I wonder whether there’s a 
> strong
> requirement for multiple nvo3 encapsulation formats on a single VNI vs. 
> forcing use of
> a separate VNI if there’s a desire for more than one encapsulation format.
>  
> Thanks,
> --David
>  
> From: Aldrin Isaac [mailto:[email protected]] 
> Sent: Tuesday, June 26, 2012 9:24 AM
> To: LASSERRE, MARC (MARC)
> Cc: Aldrin Isaac; Black, David; [email protected]; Lucy yong
> Subject: Re: [nvo3] call for adoption: draft-lasserre-nvo3-framework-02
>  
> Hi Marc, 
>  
> Thanks for the clarifications. 
>  
> Wrt my first question, should we assume that there isn't yet a consensus on 
> whether a VNI can support more than one type of VN?
>  
> Regarding one-to-one mapping of VNI to VN, this implies that an end-station 
> that needs to be a part of more than one VN will require a separate interface 
> into each associated VNI.  This implies that the end-station will require a 
> potentially complex routing table (depending on how aggregateable the address 
> space within a VN is).  Unfortunately as an operator I don't find this an 
> acceptable trade off.  Can we please address the issue of managing multiple 
> interfaces and complex tables in end-systems? I believe the problem statement 
> needs to capture this.  
>  
> Best -- aldrin
> 
> On Tuesday, June 26, 2012, LASSERRE, MARC (MARC) wrote:
> Hi Aldrin,
> 
> See my comments below.
> 
> Thanks,
> Marc
> 
> > -----Original Message-----
> > From: Aldrin Isaac [mailto:[email protected]]
> > Sent: Monday, June 25, 2012 8:23 PM
> > To: LASSERRE, MARC (MARC)
> > Cc: Lucy yong; [email protected]; [email protected]
> > Subject: Re: [nvo3] call for adoption:
> > draft-lasserre-nvo3-framework-02
> >
> > Hi Marc,
> >
> > Looking for more clarity on the following...
> >
> > Should we assume that a VNI can only support L2VNs (VNI =
> > L2VNI) or L3VNs (VNI = L3VNI) but not both?
> >
> > draft-mity-nvo3-use-cases describes a "virtual network
> > instance interconnecting interface" (VNIF) to interconnect
> > VNI of different type.  An example of a VNIF would be an IRB
> > (integrated routing and bridging) interface that is common on
> > "L3 switches".  Is this something that draft-lasserre captures?
> 
> While the current draft focuses on L2VNs and L3VNs as distinct services, no 
> assumptions have been made about the ability to support IRB.
> A couple of sentences could be added to highlight this possibility.
> 
> >
> > Are there any restriction to the topology of a VN or topology
> > created using a set of VNs.  I.e. can (1) a VNI be a member
> > of multiple VN and (2) can a VN be either hub-and-spoke or
> > full-mesh?  Does draft-lasserre support (1) and (2)?
> 
> A VN is represented by a VNI created within NVEs that participate in this VN. 
> Hence there is a one-to-one mapping between a VN and VNI.
> 
> Hub-and-spoke is discussed briefly in this draft. More details are provided 
> in draft-bl-nvo3-dataplane-requirements.
> 
> >
> > Best -- aldrin
> >
> >
> > On Jun 25, 2012, at 1:14 PM, <[email protected]> wrote:
> >
> > > Extracting a couple of items for additional comment:
> > >
> > >> 2) section 2.3, why call it NVE service type? Should we call it VN
> > >> (or VNI) service type? One NVE may terminate both L2 VNI
> > and L3 VNI.
> > >> NVE is equivalent to PE in L2VPN/L3VPN. We did not have
> > service type
> > >> for PE and had service type for VPN.
> > >>
> > >> [ml] Like with L2 and L3 PEs, there are L2 and L3 NVEs.
> > >> [[LY]] Should we consider this as VN service type? I
> > understand the
> > >> description but have trouble with the title of NVE service type.
> > >
> > > I think VN service type makes sense, as an NVE could conceivably
> > > support both
> > > L2 and L3 services for the same end system.  OTOH, mixing L2 and L3
> > > service types on the same VN requires that the
> > encapsulation indicate
> > > the service type (for correct decap processing), and that
> > would also be useful to note.
> > >
> > >> 7) It is important to state that the major difference
> > between other
> > >> overlay network technology and NVO3 is that
> > >>   the client edges of the NVO3 network are individual virtualized
> > >> hosts and not network sites.
> > >>
> > >> [ml] NVO3 can cope with both virtualized and non-virtualized hosts.
> > >> [[LY]] Yeah, that is more precise. The point is that the
> > client edge
> > >> is not network sites like CEs in a VPN.
> > >
> > > Actually the NVE can be in a network node.  See Figure 3 and the
> > > discussion of "traditional physical server" in the last
> > paragraph on
> > > p.10, including the statement that the NVE can be in the
> > ToR.  FWIW,
> > > the Storage Systems example in that paragraph is fine, although one
> > > can envision storage systems that contain NVEs.
> > >
> > > Thanks,
> > > --David
> > >
> > >> -----Original Message-----
> > >> From: [email protected] [mailto:[email protected]]
> > On Behalf
> > >> Of Lucy yong
> > >> Sent: Monday, June 25, 2012 11:52 AM
> > >> To: LASSERRE, MARC (MARC); Benson Schliesser; [email protected]
> > >> Cc: Bocci, Matthew (Matthew)
> > >> Subject: Re: [nvo3] call for adoption:
> > >> draft-lasserre-nvo3-framework-02
> > >>
> > >> Marc,
> > >>
> > >> Please see inline below with [[LY]].
> > >>
> > >> Lucy
> > >>
> > >> -----Original Message-----
> > >> From: LASSERRE, MARC (MARC)
> > [mailto:[email protected]]
> > >> Sent: Monday, June 25, 2012 9:23 AM
> > >> To: Lucy yong; Benson Schliesser; [email protected]
> > >> Cc: Bocci, Matthew (Matthew)
> > >> Subject: RE: [nvo3] call for adoption:
> > >> draft-lasserre-nvo3-framework-02
> > >>
> > >> Hi Lucy,
> > >>
> > >> Thanks for your comments.
> > >> See my comments below prefixed with [ml].
> > >>
> > >> Marc
> > >>
> > >> -----Original Message-----
> > >> From: Lucy yong [mailto:[email protected]]
> > >> Sent: Saturday, June 23, 2012 1:11 AM
> > >> To: LASSERRE, MARC (MARC); Benson Schliesser; [email protected]
> > >> Cc: Bocci, Matthew (Matthew)
> > >> Subject: RE: [nvo3] call for adoption:
> > >> draft-lasserre-nvo3-framework-02
> > >>
> > >> Marc,
> > >>
> > >> Here are some comments on this draft:
> > >>
> > >> 1) The VN (or VNI?) in the doc. is an overlay network that is
> > >> transported over the tunnels. These tunnels are provided by the

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