Re: [netext] #4: Logical interface support: Point to point links

[<[e-mail]>]

Hi Sri,

If I understand correctly, there is no violation of RFC5213 if all physical links are p2p. However the proposed text allows the virtual interface to bound physical shared links. If so, I think we may have the issue described in section 4.2 of http://tools.ietf.org/html/draft-ietf-netlmm-mn-ar-if-03. Maybe, the text should be clarified to restrict to physical p2p links.  

BR,
Pierrick 

> -----Message d'origine-----
> De : [e-mail] [mailto:[e-mail]] De la part
> de Sri Gundavelli
> Envoyé : mardi 15 mars 2011 04:04
> À : Julien Laganier
> Cc : [e-mail]
> Objet : Re: [netext] #4: Logical interface support: Point to point links
> 
> Julien:
> 
> Lets see, what is the violation here ?
> 
> - We are stating the logical interface appears to the applications as an
> interface attached to a shared link. For the simple reason, that we have
> multiple neighbors on different network segments attached through
> different
> sub-interface of that logical interface. We don't have a single
> neighbor/MAG.
> 
> - "Underneath the logical interface ...", there are sub-interfaces which
> may
> be very well attached to different p2p links. As long as the network has
> the
> semantics to send a RA with PIO, exclusively to this node, no other node
> on
> that access link can receive that Prefix set, we are confirming to 5213
> link
> model. From any of the MAG's perspective, attached to any of the access
> links, it can still be kept as a p2p link
> 
> - Exposing the logical interface as a shared link to the applications on
> the
> *mobile node*, is not violating 5213 principles. The path chosen for a
> packet through a sub-interface can be still a p2p link and the rules of
> link-layer resolution of the peer, or adding l2 headers skipping l2
> resolution, is still the approach in use.
> 
> 
> 
> 
> Sri
> 
> 
> 
> 
> 
> 
> 
> 
> On 3/14/11 5:20 PM, "Julien Laganier" <[e-mail]> wrote:
> 
> > Sri -
> >
> > 5213 supports only PtP links thus I do not understand how the
> > following resolution resolves anything. Please clarify what is the
> > issue you' re addressing and how this is addressing it.
> >
> > --julien
> >
> > On Mon, Mar 14, 2011 at 4:24 PM, Sri Gundavelli <[e-mail]>
> wrote:
> >>> #4: Logical interface support: Point to point links
> >>
> >>  Clarify the use and
> >>> behavior of the logical interface on PtP links.
> >>
> >>
> >> Folks: Again, reflecting the team's contributions on this topic, the
> authors
> >> of this document have discussed this and resolve it with the following
> text.
> >> The key points we tried to reflect are around that the logical
> interface
> >> appears to the application as a shared link. There were thoughts around
> >> making it appear like a p2p link, given that there are multiple
> neighbors on
> >> each sub interface, this choice appears reasonable. With respect to how
> a
> >> packet is transmitted, is still based on the chosen link model at each
> sub
> >> interface level. Let us know, if you see any issues with it. This is
> proven
> >> based on the multiple implementations from some of the co-authors of
> this
> >> doc.
> >>
> >>
> >>
> >>
> >> ---
> >> 6.3.  Supported Link models for a logical interface
> >>
> >>  The sub-interfaces of a logical interface can be bound to a point-to-
> >>   point or a shared link (Example: LTE and WLAN).  The logical
> >>   interface appears as a shared-link to the applications, and adapts to
> >>   the link model of the sub-interface for packet communication.  For
> >>   example, when transmitting a packet on a sub-interface which is
> >>   attached to a p2p link, the transmission conforms to the p2p link
> >>   model and when transmitting on a sub-interface attached to a shared
> >>   link, the transmission conforms to the shared link model.
> >>
> >>   Based on the link to which the sub-interface is attached to, the
> >>   layer-2 resolutions may or may not be needed.  If the interface is
> >>   bound to a P2P link with PPP running, there will not be any link-
> >>   layer resolutions in the form of ARP/ND messages.  However, if the
> >>   interface is bound to a shared link such as Ethernet, there will be
> >>   ND resolutions.  The logical interface implementation has to maintain
> >>   the required link model and the associated state for each sub-
> >>   interface.
> >> --
> >>
> >>
> >>
> >>
> >> On 3/3/11 9:17 AM, "netext issue tracker"
> <[e-mail]>
> >> wrote:
> >>
> >>> #4: Logical interface support: Point to point links
> >>
> >>  Clarify the use and
> >>> behavior of the logical interface on PtP links.
> >>
> >> --
> >>>
> >> ---------------------------------------+-------------------------------
> -----
> >>
> >>> Reporter:  basavaraj.patil@Š          |       Owner:  telemaco.melia@Š
> >>>
> >>     Type:  defect                     |      Status:  new
> >>>
> >>  Priority:  major                      |   Milestone:
> >>>
> >> Component:  logical-interface-support  |     Version:
> >>>
> >>  Severity:  -                          |    Keywords:
> >>>
> >> ---------------------------------------+-------------------------------
> -----
> >>
> >>>
> >> Ticket URL: <http://trac.tools.ietf.org/wg/netext/trac/ticket/4>
> >> netext
> >>> <http://tools.ietf.org/netext/>
> >>
> >> _____________________________________________
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> >>
> >>
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