Re: [ipwave] Some review comments for draft-ietf-ipwave-vehicular-networking-11

CARLOS JESUS BERNARDOS CANO <> Sat, 16 November 2019 05:06 UTC

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Date: Sat, 16 Nov 2019 02:10:00 +0100
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To: "Mr. Jaehoon Paul Jeong" <>
Cc: Russ Housley <>, Suresh Krishnan <>, its <>,, 김증일 글로벌R&D마스터 <>
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Subject: Re: [ipwave] Some review comments for draft-ietf-ipwave-vehicular-networking-11
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Hi Paul,

I’ve reviewed the draft. I think the draft is in better shape than last
time I checked, but it is not yet ready. I’m afraid I have quite some
comments. Please see below:

- I think the title (and the text in many parts of the document) should be
changed to refer to IPv6, instead of IP, as the document (and the WG) is
IPv6 specific. Another example: we should not mention Mobile IPv4 in the
document (as done currently in page 2).

- Page 4 (but also later in different parts of the doc): Mobility Anchor
(MA): is this term coined somewhere you can reference? It is mentioned as a
component of a vehicular architecture, but it is not discussed why, not
even why an IPv6 mobility solution is needed in a vehicular scenario. It
might seem like straightforward, but you need to present that need.

- Page 4: the terms OBU and RSU should be aligned with what the basic OCB
draft uses (IP-OBU and IP-RSU) and probably refer to that document. Besides
I understand OBU and RSUs as single IP devices, not set of nodes as the
document currently defines.

- Page 5: V2I2P and V2I2V deserve additional explanation.

- The use cases should serve not only to present areas where vehicular
networks can be used, but also to support requirements for IPv6 in such
environments. Current text does not help much on identifying requirements.

- Section 4 should introduce a generic vision of what vehicular networks
architectures might look like, again to help the purpose of identifying
requirements. I’m afraid current section is making quite a lot of
assumptions about how the architecture looks like without properly
justifying them. Examples are: the presence of a Mobility Anchor, using
Ethernet links to interconnect RSUs or the subnet/prefix model. I think the
proposed architecture might make sense, but it is not THE architecture (if
it was, we should be referring to the doc where it is specified), but an
example of potential architecture. It’d be right to present an exemplary
architecture to support the use cases and problem statement, but the
document should clearly state that.

- Related to the former, the document assumes that IPv6 mobility is a key
requirement. While I don’t disagree with that, the document should support
that assumption backed up by requirements from use cases.

- Figure 2: the vision of the RSU having multiple routers, hosts, etc,
inside... where does it come from? It’s new to me. Similarly, on the
vehicle I’d expect Router1 to be an IP-OBU. Related to this comment, first
paragraph of Section 4.2 talks about the RSU architecture without providing
any reference. Why is it needed to have a DNS server internally? I don’t
see why this is needed or specific to vehicular networks.

- Page 12: all the discussion about the need for exchanging prefix
information comes out of the blue, there is no proper discussion why this
is a requirement. And then the document gets into mentioning an example of
solution for this, which is something that should be avoided (this document
is not about solution space), unless we were analyzing different approaches
to solve a given problem.

- Page 12: as mentioned above, I don’t see why we need the DNS discussion.

- Figure 2 makes assumptions on network topology and subnetting that is not

- Page 14: the discussion on prevention of false reports of accidents is
application-layer specific, not IPv6 specific, and therefore it is not in
the scope of this document.

- Section 5.1 is a critical one (actually the whole section 5) and I think
it needs significant work. I’d discuss link model issues before going into
neighbor discovery protocol specific issues. Current text seem to have
already a solution in mind when describing the issues, while what it should
do is derive requirements, and explain why current solutions are not
sufficient. For example, it should not start saying that DAD and ND-related
parameters need to be extended before introducing why current DAD and ND is
not sufficient.

- All the discussion on ND timers is again very much solution specific and
should be avoided. And the discussion about NHTSA and the collision is also
not appropriate, as one thing is the delay at application layer and a
different thing is the timers used for ND.

- Page 16 and page 17: the text assumes a prefix model for a vehicular
network that is not properly introduced and justified. Issues cannot be
derived from the use of a prefix model that is not well introduced.

- Page 18: the discussion about notifying changes on the IP address should
be removed if it is assumed that there is an IPv6 mobility protocol in
place (which seems to be the case) as this is taken care by it.

- Section 5.1.3: again it goes too much into solution space without
presenting the scenario and the issues. This document is not about talking

- Section 5.2: same comment as before. Solution space specifics should be

- Section 6 needs significant work as well. First, I’d like to have some
kind of structure in terms of presenting the security and privacy issues
that are specific to the vehicular environment. And then, we need to have a
list of issues/requirements instead of again going too much into solution

We can sit together in Singapore to discuss about how to address these



On Thu, 7 Nov 2019 at 08:30, Mr. Jaehoon Paul Jeong <>

> Carlos,
> Great!
> Sure you soon in Singapore.
> Thanks.
> Paul
> On Thu, Nov 7, 2019 at 9:08 AM CARLOS JESUS BERNARDOS CANO <
>> wrote:
>> Hi Paul,
>> I have to do my review first. You'll have it by the Singapore meeting so
>> we can discuss there.
>> Thanks,
>> Carlos
>> On Wed, Nov 6, 2019 at 3:29 AM Mr. Jaehoon Paul Jeong <
>>> wrote:
>>> Hi Carlos,
>>> I am wondering what next steps our IPWAVE PS draft will take.
>>> If you are satisfied with my revision, could you do the WG Last Call on
>>> this version?
>>> Thanks.
>>> Best Regards,
>>> Paul
>>> On Fri, Oct 4, 2019 at 1:19 AM CARLOS JESUS BERNARDOS CANO <
>>>> wrote:
>>>> Hi Paul,
>>>> Thanks for the revision. I'll review the document and let you know
>>>> about next steps.
>>>> Carlos
>>>> On Thu, Oct 3, 2019 at 12:12 PM Mr. Jaehoon Paul Jeong <
>>>>> wrote:
>>>>> Hi Russ and Carlos,
>>>>> I have submitted the revision (-12) of IPWAVE PS draft as you know.
>>>>> Will you review the revision and move forward to the WGLC or wait for
>>>>> Charlie's another review?
>>>>> BTW, my SKKU team are working for IETF-106 IPWAVE Hackathon Project to
>>>>> show the data delivery
>>>>> between two 802.11-OCB embedded systems such as the text and
>>>>> web-camera video.
>>>>> We will work to demonstrate the IPv6 over 802.11-OCB.
>>>>> This is a collaboration work with Hyundai Motors.
>>>>> Thanks.
>>>>> Best Regards,
>>>>> Paul
>>>>> ---------- Forwarded message ---------
>>>>> From: Mr. Jaehoon Paul Jeong <>
>>>>> Date: Thu, Oct 3, 2019 at 6:57 PM
>>>>> Subject: Re: [ipwave] Some review comments for
>>>>> draft-ietf-ipwave-vehicular-networking-11
>>>>> To: Charlie Perkins <>
>>>>> Cc: <>, Sandra Cespedes <
>>>>>>, <>, Mr. Jaehoon
>>>>> Paul Jeong <>
>>>>> Hi Charlie,
>>>>> I have addressed your comments below and your editorial changes,
>>>>> submitting the revision:
>>>>> Also, I addressed Sandra's comments about the definition of an RSU as
>>>>> an edge computing system
>>>>> having multiple routers and servers (including DNS server), as shown
>>>>> in Figure 2.
>>>>> I attach the revision letter for your double-checking.
>>>>> Thanks for your valuable and constructive comments.
>>>>> Best Regards,
>>>>> Paul
>>>>> On Mon, Sep 16, 2019 at 1:08 PM Charlie Perkins <
>>>>>> wrote:
>>>>>> Hello folks,
>>>>>> I made a review of the document
>>>>>> draft-ietf-ipwave-vehicular-networking-11.txt.  Besides editorial
>>>>>> comments, I had some other more substantive comments on the document,
>>>>>> as
>>>>>> follows.
>>>>>> First, I thought that the document should contain an easily
>>>>>> identifiable
>>>>>> problem statement.  Here is some text that I devised for that
>>>>>> purpose,
>>>>>> which could fit naturally at the beginning of Section 5.
>>>>>>     In order to specify protocols using the abovementioned
>>>>>> architecture
>>>>>>     for VANETs, IPv6 core protocols have to be adapted to overcome
>>>>>> certain
>>>>>>     challenging aspects of vehicular networking.  Since the vehicles
>>>>>> are
>>>>>>     likely to be moving at great speed, protocol exchanges need to be
>>>>>>     completed in a time relatively small compared to the lifetime of a
>>>>>>     link between a vehicle and an RSU, or between two vehicles.  This
>>>>>>     has a major impact on IPv6 neighbor discovery. Mobility management
>>>>>>     is also vulnerable to disconnections that occur before the
>>>>>> completion
>>>>>>     of identify verification and tunnel management.  This is
>>>>>> especially
>>>>>>     true given the unreliable nature of wireless communications.
>>>>>> Finally,
>>>>>>     and perhaps most importantly, proper authorization for vehicular
>>>>>> protocol
>>>>>>     messages must be assured in order to prevent false reports of
>>>>>> accidents
>>>>>>     or other mishaps on the road, which would cause horrific misery in
>>>>>>     modern urban environments.
>>>>>> ----------------------------------------------
>>>>>> Although geographic routing is mentioned early in the document, it is
>>>>>> not discussed in later sections.  This makes me wonder whether the
>>>>>> early
>>>>>> mention is really relevant.  In fact, for fast moving objects, I
>>>>>> think
>>>>>> it is already questionable whether geographic routing has value.  For
>>>>>> the RSUs, it is a lot easier to imagine a good use for geographic
>>>>>> routing, or perhaps some other use of geographic information to
>>>>>> establish links between application endpoints.  If geographic
>>>>>> algorithms
>>>>>> are mentioned at all, a lot more development is needed to establish
>>>>>> relevance to the problem statement.
>>>>>> ---------------------------------------------
>>>>>> More description is needed for OCB in the Terminology section. It
>>>>>> would
>>>>>> also be a good idea to include definitions for "context-aware" and
>>>>>> for
>>>>>> platooning.
>>>>>> class-based safety plan needs a definition and a list of classes.
>>>>>> ---------------------------------------------
>>>>>> As a general comment, it seems to me that a proposed architecture is
>>>>>> usually considered to be part of the solution, not the problem
>>>>>> statement.  In the case of this document, the architecture is really
>>>>>> a
>>>>>> depiction of IPv6 as it might be normally considered to live in a
>>>>>> multi-network deployment (e.g., between a lot of cars and RSUs).  But
>>>>>> anyway some care has to be taken so that the proposed architecture
>>>>>> doesn't otherwise place strong limits on acceptable solutions.  So,
>>>>>> for
>>>>>> example, in section 4.1, it needs to be clear whether or not a single
>>>>>> subnet prefix can span multiple vehicles.  This is an important
>>>>>> choice.
>>>>>> ---------------------------------------------
>>>>>> In section 5.1.1., a claim is made that a new link model is
>>>>>> required.  I
>>>>>> think this is a very ambitious claim, and I am not even quite sure
>>>>>> what
>>>>>> is meant.  IPv6 already provides for "on-link" and "off-link"
>>>>>> variations
>>>>>> on subnet operation.  Unless I am missing something here, the claim
>>>>>> should be made much more clear (or else retracted).
>>>>>> Similarly, the suggestion that VANETs need to be merging and
>>>>>> partitioning as part of the problem statement seems at least
>>>>>> ambitious
>>>>>> and might present a very high bar that could disqualify otherwise
>>>>>> suitable solutions.
>>>>>> ---------------------------------------------
>>>>>> It would be nice to have a citation about why current implementations
>>>>>> of
>>>>>> address pseudonyms are insufficient for the purposes described in
>>>>>> section 5.1.2.
>>>>>> ---------------------------------------------
>>>>>> It seems to me that the discussion in section 5.1.3 lives almost
>>>>>> entirely in solution space.
>>>>>> ---------------------------------------------
>>>>>> In section 5.1.4, it was not clear to me about why Neighbor Discovery
>>>>>> really needs to be extended into being a routing protocol.
>>>>>> --------------------------------------------
>>>>>> It seems to me that section 5.3 really belongs in section 6. Also,
>>>>>> even
>>>>>> a perfectly authorized and legitimate vehicle might be persuaded
>>>>>> somehow
>>>>>> to run malicious applications.  I think that this point is not
>>>>>> sufficiently covered in the current text.
>>>>>> Regards,
>>>>>> Charlie P.
>>>>>> Blue Sky Networks
>>>>>> _______________________________________________
>>>>>> its mailing list
>>>>> --
>>>>> ===========================
>>>>> Mr. Jaehoon (Paul) Jeong, Ph.D.
>>>>> Associate Professor
>>>>> Department of Software
>>>>> Sungkyunkwan University
>>>>> Office: +82-31-299-4957
>>>>> Email:,
>>>>> Personal Homepage:
>>>>> <>
>>>>> --
>>>>> ===========================
>>>>> Mr. Jaehoon (Paul) Jeong, Ph.D.
>>>>> Associate Professor
>>>>> Department of Software
>>>>> Sungkyunkwan University
>>>>> Office: +82-31-299-4957
>>>>> Email:,
>>>>> Personal Homepage:
>>>>> <>
>>>> --
>>>> Special Issue "Beyond 5G Evolution":
>>> --
>>> ===========================
>>> Mr. Jaehoon (Paul) Jeong, Ph.D.
>>> Associate Professor
>>> Department of Software
>>> Sungkyunkwan University
>>> Office: +82-31-299-4957
>>> Email:,
>>> Personal Homepage:
>>> <>
>> --
>> Special Issue "Beyond 5G Evolution":
> --
> ===========================
> Mr. Jaehoon (Paul) Jeong, Ph.D.
> Associate Professor
> Department of Software
> Sungkyunkwan University
> Office: +82-31-299-4957
> Email:,
> Personal Homepage:
> <>
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