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

[Sri Gundavelli <[e-mail]>]

Hi Pierrick,

The sentence can be reworded. Agree, the link model between the MAG and the
MN is still a point-to-point link. From 5213 perspective, as long as the
point-to-point communication semantics are there between the MN and MAG, we
meet the requirement and there is no protocol violation.  How that P2P link
model is achieved, based a tunnel interface, putting the access point in a
unicast mode, are all the possible options.



Sri



On 3/15/11 1:21 AM, "[e-mail]"
<[e-mail]> wrote:

> 
> 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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