> On 20 Feb 2018, at 14:34, Pascal Thubert (pthubert) <[email protected]> 
> wrote:
> 
> Hello Tim
> 
> Thanks a bunch again. I think we are all set now, and I will publish the 
> result as -12.

Great!

> Please see below:
> 
>> 
>>> new updated proposed text:
>> 
>> "
>>   <t> The IPv6 address of the 6LN in the IPv6 header can be compressed
>>   statelessly Interface Identifier in the IPv6 address can be derived 
>> from
> 
>> TC> Insert "where the" after statelessly?
> 
> PT> "when the" in fact, no?

TC> Either works for me.

> ********************
> 
> 
>>   the Lower Layer address. When it is not critical to benefit from that 
>>   compression, e.g. the address can be compressed statefully, or it is rarely
>>   used and/or it is used only over one hop, then the best practice of forming
>>   privacy addresses should be considered:
>>   </t>
>>   <t> <xref target="RFC7217">"A Method for Generating Semantically Opaque
>>   Interface Identifiers with IPv6 Stateless Address Autoconfiguration 
>> (SLAAC)"
>>   </xref> is the recommended method for generating Interface Identifiers to 
>>   be used in SLAAC at the time of this writing.
>>   </t>
> 
>> TC> I'd be careful referring to privacy addresses and then implying RFC7217 
>> gives a privacy address, given a node could have an RFC7217 address and a 
>> RFC4941 privacy address, or potentially just a privacy address.
> 
> PT> Sorry Tim I do not know what action I can take here. This goes probably 
> beyong the scope of this document, which does not standardize the address 
> generation anyway.

TC> Then perhaps just say that when compression is not critical to have, then 
RFC 8064 should be followed, which recommends use of RFC 7217.  

>> **********************
> 
>> 
>> p.22
>> What trust model?
>> 
>>> Should I add words? Those networks are always protected at Layer 2. But 
>>> really, we'd like to see a draft that enables a 6LBR to prove it has that 
>>> capacity and is entitled to play the role for the network. This is beyond 
>>> the scope of this particular draft and should be done in a security related 
>>> 6LoWPAN draft.
> 
> TC> OK, perhaps just explicitly state the presence / assumption of L2 
> protection in the security section.
> 
> PT> Added:
> 
> "   This trust model could be
>    at a minimum based on a Layer-2 access control, or could provide role
>    validation as well (see Req5.1 in <xref target="Req5"/>).
> "
> 
>> **********************
> 
>> 
>> 
>> p.4
>> Section 2 last para - "their" rather than "his"
>> 
>>> sorry I do not see this ? the "his" refers to the network admin.
> 
> TC> In more politically correct British English, you'd say "their" as a 
> gender neutral term, not "his".  In the case "their" can be singular.
> 
> PT> oh, got you.

No problem.

Best wishes,
Tim

> 
> 
>> Thanks a bunch again for your deep review Tim!
> 
> TC> It was a good read, and very interesting.
> 
> Take care,
> 
> Pascal
> 
> -----Original Message-----
> From: Tim Chown [mailto:[email protected]] 
> Sent: mardi 20 février 2018 12:33
> To: Pascal Thubert (pthubert) <[email protected]>
> Cc: [email protected]; [email protected]; [email protected]
> Subject: Re: [Int-dir] [6lo] Intdir early review of 
> draft-ietf-6lo-rfc6775-update-11
> 
> Hi Pascal,
> 
>> On 20 Feb 2018, at 10:13, Pascal Thubert (pthubert) <[email protected]> 
>> wrote:
>> 
>> 
>> Reviewer: Tim Chown
>> 
>> Thanks a bunch Tim!
>> 
>> I answered with a prefix >
>> 
>> There are specific questions back to you down there. Please feel free to 
>> remove all Q/As for which we found an agreement already.
>> 
>> General comments:
>> --------------------------------------
>> 
>> The document could use a glossary of terms: LLN, 6LN, 6LBR, 6LR, BBR, etc.
>> 
>>> Done in appendix
>> 
>> 
>> *******************
>> 
>> The introduction could talk of other new added features, like avoiding DAD 
>> for link locals.
>> 
>>> You'll note that it is not avoided. But it is scoped in the relationship 
>>> between the 6LN and the 6LR. One 6LR may accept to talk to a 6LN LN_A seen 
>>> as LLA Addr_A and then later another 6LR may refuse that same Addr_A 
>>> because from its standpoint Addr_A duplicates a LLA used by another device 
>>> that is also talking to. The draft does not change what a LLA can be used 
>>> for in route over, that is one radio hop; mostly, it reduces the illusion 
>>> that a link local address can be DAD'ed in a network that is not fully and 
>>> permanently connected. 
> 
> TC> OK, thanks for the clarification.
> 
>>> Added:
>> "
>>   <t> Simplify the registration flow for link-local addresses </t>
>> "   
>>   as a clarification instead of: 
>> "    
>>   <t> Reduce requirement of registration for link-local addresses 
>> </t> "
> 
> TC> OK.
> 
>> The document includes RFC 7217 in the references, but doesn't include 
>> discussion of it in the main body of the text.  Shouldn't RFC 7217 be 
>> considered the norm here rather than address generation as per RFC 4862? 
>> 
>>> added:
>> 
>> "
>>   <t> <xref target="RFC7217">"A Method for Generating Semantically Opaque
>>   Interface Identifiers with IPv6 Stateless Address Autoconfiguration 
>> (SLAAC)"
>>   </xref> is the recommended method for generating Interface Identifiers to 
>>   be used in SLAAC at the time of this writing.
>>   </t>
>> "
>> 
>> 
>> **********************
>> 
>> 
>> 
>> Related, RFC 8064 "recommends against embedding stable link-layer 
>> addresses in
>> IPv6 Interface Identifiers".  The document is inconsistent - it talks of 
>> using EUI64, then in Section 9 not using EUI64.
>> 
>>> fact is, a typical IEEE802.15.4-based network will compress the IPv6 
>>> address based on the MAC address. But it does not have to be so, and it 
>>> does not apply to all types of networks.
>> 
>>> new updated proposed text:
>> 
>> "
>>   <t> The IPv6 address of the 6LN in the IPv6 header can be compressed
>>   statelessly Interface Identifier in the IPv6 address can be derived 
>> from
> 
> TC> Insert "where the" after statelessly?
> 
>>   the Lower Layer address. When it is not critical to benefit from that 
>>   compression, e.g. the address can be compressed statefully, or it is rarely
>>   used and/or it is used only over one hop, then the best practice of forming
>>   privacy addresses should be considered:
>>   </t>
>>   <t> <xref target="RFC7217">"A Method for Generating Semantically Opaque
>>   Interface Identifiers with IPv6 Stateless Address Autoconfiguration 
>> (SLAAC)"
>>   </xref> is the recommended method for generating Interface Identifiers to 
>>   be used in SLAAC at the time of this writing.
>>   </t>
> 
> TC> I'd be careful referring to privacy addresses and then implying RFC7217 
> gives a privacy address, given a node could have an RFC7217 address and a 
> RFC4941 privacy address, or potentially just a privacy address.
> 
>> "
>>   this is followed by existing text:
>> "    
>>   <t>
>>      <xref target="RFC8065">
>>      "Privacy Considerations for IPv6 Adaptation-Layer Mechanisms"</xref>
>>      explains why privacy is important and how to form such addresses.  All
>>      implementations and deployment must consider the option of privacy
>>      addresses in their own environment.  Also future specifications
>>      involving 6LoWPAN Neighbor Discovery should consult
>>      <xref target="RFC8064">
>>      "Recommendation on Stable IPv6 Interface Identifiers"</xref>
>>      for default interface identification.
>>   </t>
>> "
>> 
>> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> 
>> 
>> Specific comments:
>> --------------------------------------
>> 
>> p.3
>> Section 2, para 2 - should ND cache exhaustion attacks be included in the 
>> list here?
>> 
>>> If the method is used as a full replacement of reactive ND, then there can 
>>> be some control. e.g. we'd be immune from NCE DOS attack from a remote 
>>> party. But it's a touchy space. In the one hand, we never block from using 
>>> both, IOW classical (reactive) ND in conjunction with the new (proactive) 
>>> registration. Also a local node could still attack the cache by performing 
>>> tons of registrations, forging MAC addresses as it goes if need be.  It 
>>> will take separate work to address all the security requirements (AP-ND 
>>> https://tools.ietf.org/html/draft-ietf-6lo-ap-nd and more).
> 
> TC> OK, so leave as is.
> 
>> 
>> **********************
>> 
>> 
>> 
>> p.4
>> Section 3 - Add RFC 7217 to RFC 4862?  It's recommended by RFC 8064.
>> 
>>> This is a terminology section. Are there terms we need from RFC 7217? Note 
>>> that this specification does not dictate how to form address, just manages 
>>> them. Still it places recommendation to the protocol developers coming next 
>>> (e.g. for a particular link layer) to consider privacy. Text related to RFC 
>>> 7217 is added in section 9 per your other comment.
> 
> TC> OK, leave as is then.
> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.6
>> Section 4 - for a node to prefer registering to a 6LR that supports the 
>> spec, it would need to enumerate all available 6LRs; should the process for 
>> this be described here, or is it included in sufficient detail in RFC 6775?
>> 
>>> You are correct. There is no enumeration process; 6LRs are discovered as 
>>> described in RFC 6775 sections 5.2 and 5.3. by sending out mcast RS. This 
>>> document updates RFC 6775 but we avoided paraphrasing it as much as we 
>>> could, considering that this doc is already quite thick. 
>> Still I added the first line of the text below:
>> "
>>   <t> Section 5 of <xref target="RFC6775"/> specifies how a 6LN bootstraps an
>>   interface and locates available 6LRs; a Registering Node SHOULD prefer
>>      registering to a 6LR that is found to support this specification, as
>>      discussed in <xref target="dsc"/>, over a legacy one.
>>   </t>
> 
> TC> OK.
> 
>> "
>> 
>> 
>> **********************
>> 
>> 
>> 
>> 
>> p.7
>> Section 4.1 - "not required to be a MAC address" - as per my general comment 
>> above, with current IETF thinking, should this not be stronger, e.g. "SHOULD 
>> NOT be a MAC address"?  Section 9 says this?
>> 
>>> I see where you're coming from and htat makes sense to me. But the WG never 
>>> went that far. Note that this is not a subfield in an address; as it goes 
>>> the message is not not supposed to leak outside. RFC 6775 forced the UID to 
>>> be a MAC address in the EUI-64 form. This specification does not deprecate 
>>> the legacy behavior and it allows for something else.  But it recommends 
>>> (section 8) to use a privacy technique such as AP-ND instead. Once AP-ND is 
>>> standard, we can deprecate the legacy behavior if the WG finds it relevant, 
>>> e.g. when we apply it to networks that are more sensitive to privacy.
> 
> TC> OK, thanks for explaining it; that sounds reasonable. I suspect this 
> point will come up again in IESG review though!
> 
>> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> 
>> p.9
>> Section 4.2, point 4 - I find this quite para quite hard to read.
>> 
>>> Agreed, it is inlined from RFC 6550 as opposed to referenced per WG and 
>>> shepherd decision. I simplified to:
>> "            
>>              If two sequence numbers are determined to be not comparable,
>>              i.e. the results of the comparison are not defined, then a node
>>              should give precedence to the sequence number that was most 
>> recently
>>       incremented. Failing this, the node should select the sequence number 
>>       in order to minimize the resulting changes to its own state.
>> 
>> "
> 
> TC> OK.
> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.9
>> Section 4.3, para 1 - again, is using EUI-64 desirable?  Is the point to 
>> allow header compression as per RFC4944?  Discuss the tradeoff? Section 4.3 
>> para 2 - so a different type of identifier could be an RFC 7217 generated 
>> identifier?
>> 
>>> It could be many things but collisions should be avoided. It should not be 
>>> an interface ID since this is to complement the DAD of the IID. AP-ND 
>>> builds it on cryptography. Your point is excellent, unsure if this doc 
>>> should be the vessel for it. At this stage, we never argued deprecation 
>>> before, just extension. It will take WG work to define possible 
>>> replacements and this doc may be too advanced for that I guess, but I'll 
>>> ask.
> 
> TC> OK.
> 
>> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.11
>> Section 4.6 - in the case of two 6LRs with the same link-layer addresses, 
>> does it matter which a 6LN chooses?  Is the choice algorithmic? Section 4.6 
>> - the last para on p.11 seems to be repeated in the first para on p.12?
>> 
>>> This specification (including RFC 6775) does not have a router preference 
>>> (whether they have a same or different LLA) beyond RFC 4191. RPL does, 
>>> based on Rank and the upcoming enrollment specification will also hint on 
>>> that. And apparently yes to your other point, cleaning up.
> 
> TC> OK.
> 
>> 
>> **********************
>> 
>> 
>> 
>> p.12
>> Section 4.6 - again, is the recommendation to use an (expected to be) unique 
>> LL address in keeping with RFC 8064?
>> 
>>> There is a chicken and an egg problem with the first registration of the 
>>> first LLA. It is better that it does not fail. RFC6775 stipulates that 
>>> MAC-derived LLA do not need DAD. This message flies over one hop, between a 
>>> node and its nearby router. The node may then form as many privacy LL and 
>>> GUA as it likes. 
> 
> TC> OK.
> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.13
>> Para 4 - a Moved message SHOULD be used, yet elsewhere a node MUST clean up 
>> its stale state?  Consistent? What about MIPv6-like spoofing security 
>> issues? You say "an alternate protocol" - isn't this a little hand-wavy; 
>> shouldn't a single mechanism be defined rather than multiple (undefined) 
>> mechanisms?
>> 
>>> Agreed. That single mechanism is DAR/DAC. I removed the "an alternate 
>>> protocol"; what was meant is now separately drafted in 
>>> draft-thubert-roll-unaware-leaves. This is where using RPL to proxy the 
>>> registration is described. Unsure about which MIP attack you have in mind?
> 
> TC> Never mind; I saw other AP-ND comments that clarified it.  
> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> 
>> p.15
>> OUI is a confusing choice of term, given OUIs in MAC addresses; I guess this 
>> is now baked into RFC 6775 though.
>> 
>>> Actually no. RFC 6775 uses EUI-64 throughout. We picked that term to 
>>> generalize the EUI-64, so I guess we can still change that name. I changed 
>>> it to Registration Unique ID (RUID) but that does not sound so right; would 
>>> you have suggestions?
>>> I'll take that question to the WG separately.
> 
> TC> I saw that, thanks. I don't have a specific suggestion, just that OUI has 
> a very well known application elsewhere.
> 
>> **********************
>> 
>> 
>> 
>> p.16
>> I don't think codes 5 and 10 are explained/defined in any detail here?  How 
>> is the challenge made?
>> 
>>> This is used in a freference spec. I clarified that by adding 3 lines at 
>>> the end of the text in the RUID (ex OUID) section which now reads:
>> 
>> "    The Registration Unique ID in <xref target="RFC6775"/>
>>      is a EUI-64 globally unique address configured at a Lower Layer,
>>      under the assumption that duplicate EUI-64 addresses are avoided.
>>      With this specification, the Registration Unique ID is allowed to be
>>   extended to different types of identifier, as long as the type is clearly
>>      indicated. For instance, the type can be a cryptographic string and
>>      used to prove the ownership of the registration as discussed in
>>      <xref target="I-D.ietf-6lo-ap-nd">
>>      "Address Protected Neighbor Discovery for Low-power and Lossy Networks"
>>      </xref>. In order to support the flows related to the proof of 
>> ownership,
>>   this specification introduces new status codes "Validation Requested" and
>>   "Validation Failed" in the EARO. 
> 
> TC> OK.
> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.16
>> The registration lifetime is in minutes; why not in seconds?
>> 
>>> RFC 6775 is missing a way to express the time unit (RPL has one). 
>> We used minutes because a typical LLN operates at a very slow pace, and a 
>> typical device is like a three-toed sloth that would sleep more than a cat. 
>> We even had a requirement to produce an 'infinite' lifetime for the likes of 
>> light bulbs but never took it that slow. We could change the format but that 
>> would not be backward compatible.
>>> I'll take that question to the WG separately
> 
> TC> :)
> 
> 
>> **********************
>> 
>> 
>> 
>> p.18
>> Section 6.3 - SHOULD set the E flag; why not a MUST?  Why would you 
>> support the spec, but not advertise that you do?  In contrast, on the 
>> next page in Section
>> 7.1.1 you say nodes MUST set it.
>> 
>>> fixed, it was a MUST :)
> 
> TC> OK.
> 
>> **********************
>> 
>> 
>> 
>> p.19
>> Section 7.1.2 para 2 - would a LL address generally be used here as source? 
>> Should that be a SHOULD?  Using a temporary address is probably not ideal.
>> 
>>> RFC 6775 used the registered address (LL or GUA) as source and the target 
>>> was not really important. With this specification, register the target of 
>>> the NS, and there is no point remembering the source address of the 
>>> registration NS after the NA was sent back. A 6LR can talk to the 
>>> registered address using the registered address.
> 
> TC> OK.
> 
>> 
>> **********************
>> 
>> 
>> 
>> p.20
>> Section 7.3 para 4 - is this consistent with p.19 last para saying a 6LN 
>> MUST use the updated spec once it knows it's supported? The last two paras 
>> here are a bit vague/loose.
>> 
>>> I turned the text into:
>> 
>> "        After detecting a legacy 6LR, an updated 6LN SHOULD attempt to find 
>> an
>>          alternate 6LR that is updated for a reasonable time that depends on 
>> the
>>       type of device and the expected deployment.
>> "
> 
> TC> OK.
> 
>> **********************
>> 
>> 
>> 
>> p.21
>> Section 8, para 3 - recommends using privacy techniques, but uses EUI64?
>> 
>>> RFC 6775 uses EUI. AP-ND uses a cryptographically generated token instead. 
>>> This section effectively recommends AP-ND or whatever else cmes next that 
>>> has privacy concerns.
> 
> TC> OK.
> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.22
>> Limit the number of addresses?  What about RFC 7934?
>> The type of algorithm described here might be better defined generically for 
>> 6LoWPAN and 'real' IPv6?  I don't think anything has been defined for ND 
>> cache exhaustion attack mitigation - would a separate draft be beneficial? I 
>> suspect current solutions are vendor specific?
>> 
>>> We applied wisdom from RFC9734 and removed text that indicated that an 
>>> administrator could be on the path of accepting an address or not. I know 
>>> for having coded it that yes, (at least some) vendors provide a protection 
>>> in the number of addresses that can be registered or snooped from a given 
>>> device wen there is a limit for the overall resources to serve the network. 
>>> A classical NCE is a cache but a 6LR NCE is really a hard state that the 
>>> registrar guarantees to maintain for a given lifetime. The fact that a 
>>> protection can be configured does not force a user in a particular 
>>> deployment  to use that protection. I agree that there is a need for NCE 
>>> attack mitigation for both classical ND and 6LoWPAN ND. But till that spec 
>>> exists, we cannot force the 6LR device to drop all protection against a 
>>> misbehaving 6LN. A 6LR is an IOT device and it might easily be pushed 
>>> beyond capacity. 
> 
> TC> OK. It might be something to raise in 6man, to see if there's interest in 
> documenting algorithm(s).
> 
>> **********************
>> 
>> 
>> 
>> p.22
>> What trust model?
>> 
>>> Should I add words? Those networks are always protected at Layer 2. But 
>>> really, we'd like to see a draft that enables a 6LBR to prove it has that 
>>> capacity and is entitled to play the role for the network. This is beyond 
>>> the scope of this particular draft and should be done in a security related 
>>> 6LoWPAN draft.
> 
> TC> OK, perhaps just explicitly state the presence / assumption of L2 
> protection in the security section.
> 
>> **********************
>> 
>> 
>> 
>> p.22
>> Section 9 - EUI64, or not EUI64?  Inconsistent.
>> Does anyone really use SeND?  Especially in 6LoWPAN networks?
>> 
>>> There are 2 uses of EUI that must be differentiated. The OUID (now RUID) is 
>>> a unique ID for the device to correlate registrations for DAD between 
>>> honest people. This section ere talks about IID in the IPv6 address. The 
>>> text explains that no, SEND cannot be used in that space. This is why we do 
>>> AP-ND instead. With AP-ND, the OUID is used to prove cryptographically the 
>>> ownership of the registered address a bit like CGA does, but it is not part 
>>> of the address. It is stored upon the first registration f an address and 
>>> used later to validate that the new registration comes from the same guy.
> 
> TC> Aaah, right, thanks.
> 
>> **********************
>> 
>> 
>> 
>> p.24
>> Section 10.3 - statuses 5 and 10 are not detailed in the draft?
>> 
>>> Added text upon your point earlier
> 
> TC> OK.
> 
>> **********************
>> 
>> 
>> 
>> p.30
>> The multicast issues text could cite the new mboned draft on this topic.
>> "Plague" is maybe strong!
>> 
>>> done the ref. Added draft-perkins as well. replaced "plague" with "affect 
>>> the operation of"
> 
> TC> OK.
> 
>> **********************
>> 
>> 
>> 
>> p.30
>> Appendix B - can we have a table showing WHICH requirements have been met by 
>> the draft?
>> 
>>> added
>> 
>> <t>
>> Note to RFC Editor: please replace "This" by the RFC number for this 
>> specification once it is attributed.
>> <t>
>> 
>>      <texttable anchor="reqadd" title="Addressing requirements">
>>      <preamble>I-drafts/RFCs addressing requirements</preamble>
>>                              <ttcol align="left"> Requirement</ttcol>
>>                              <ttcol align="left"> Document </ttcol>
>> 
>>        <c>Req1.1</c>         <c><xref 
>> target="I-D.ietf-6lo-backbone-router"/></c>
>>        <c>Req1.2</c>         <c><xref target="RFC6775"/></c>
>>        <c>Req1.3</c>         <c><xref target="RFC6775"/></c>
>>        <c>Req1.4</c>         <c>This</c>
>> 
>>        <c>Req2.1</c>         <c>This</c>
>>        <c>Req2.2</c>         <c>This</c>
>>        <c>Req2.3</c>         <c></c>
>> 
>>        <c>Req3.1</c>         <c>Technology Dependant</c>
>>        <c>Req3.2</c>         <c>Technology Dependant</c>
>>        <c>Req3.3</c>         <c>Technology Dependant</c>
>>        <c>Req3.4</c>         <c>Technology Dependant</c>
>> 
>>        <c>Req4.1</c>         <c>This</c>
>>        <c>Req4.2</c>         <c>This</c>
>>        <c>Req4.3</c>         <c><xref target="RFC6775"/></c>
>> 
>>        <c>Req5.1</c>         <c></c>
>>        <c>Req5.2</c>         <c><xref target="I-D.ietf-6lo-ap-nd"/></c>
>>        <c>Req5.3</c>         <c></c>
>>        <c>Req5.4</c>         <c></c>
>>        <c>Req5.5</c>         <c><xref target="I-D.ietf-6lo-ap-nd"/></c>
>>        <c>Req5.6</c>         <c><xref 
>> target="I-D.struik-lwip-curve-representations"/></c>
>>        <c>Req5.7</c>         <c><xref target="I-D.ietf-6lo-ap-nd"/></c>
>>        <c>Req5.8</c>         <c> </c>
>>        <c>Req5.9</c>         <c><xref target="I-D.ietf-6lo-ap-nd"/></c>
>> 
>>        <c>Req6.1</c>         <c>This</c>
>>        <c>Req6.2</c>         <c>This</c>
>> 
>>      </texttable>    <!-- end table "Addressing requirements" -->
>> 
>> 
> 
> TC> OK.
> 
> 
>> **********************
>> 
>> 
>> 
>> Nits:
>> --------------------------------------
>> 
>> p.4
>> Section 2 - "form and use multiple addresses" (add multiple)
>> 
>>> done
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.4
>> Section 2 last para - "their" rather than "his"
>> 
>>> sorry I do not see this ? the "his" refers to the network admin.
> 
> TC> In more politically correct British English, you'd say "their" as a 
> gender neutral term, not "his".  In the case "their" can be singular.
> 
> 
>> **********************
>> 
>> 
>> 
>> p.6
>> "provides new" -> "provide new"
>> 
>>> done
>> 
>> **********************
>> 
>> 
>> 
>> p.10
>> "route-over mesh" - add to definitions section
>> 
>>> added reference to RFC 6606 in the terminology section
>> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.12
>> First line of last para needs rewriting - "If the registry in the 6LBR is be 
>> saturated, in which case the LBR".
>> 
>>> I had spoted that one too : ) fixed as
>> 
>> "
>>      If the registry in the 6LBR is saturated, the
>>      LBR cannot guarantee that a new address is effectively not a duplicate.
>> "
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.13
>> Could forward reference the summary of error codes in 6.1 or 10.3 here?
>> 
>>> done
>> 
>> **********************
>> 
>> 
>> 
>> p.14
>> "removes silently" -> "silently removes"
>> "LLNs meshes" -> "LLN meshes"
>> 
>>> done
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.15
>> Code 3; change tense to past tense, e.g. "fails" to "failed"
>> 
>>> done
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.19
>> "capabilities" -> "capabilities is"
>> "such address" -> "such an address"
>> "in a" -> "in"
>> "6LB" -> "6LN" ?
>> 
>>> done. 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.21
>> "amlways" -> "always"
>> "to using" -> "using"
>> Missing close bracket for See Section 9.
>> 
>> 
>> 
>> **********************
>> 
>> 
>> 
>> p.30
>> Do you mean "sequence"?
>> "serves" -> "serves the"
>> 
>>> changed to
>> "    This specification extends 6LoWPAN ND to provide a sequence number to 
>> the
>>   registration and ...
>> "
>> 
>> **********************
>> 
>> 
>> 
>> 
>> p.31
>> "timely" -> "in a timely fashion" ?
>> B.1 last req - reword this.
>> The BIER Architecture is now an RFC I think?
>> 
>>> will fix the reference to RFC 8279
> 
> TC> All the nit comments / resolutions are fine.
> 
>> Thanks a bunch again for your deep review Tim!
> 
> TC> It was a good read, and very interesting.
> 
> Best wishes,
> Tim
> 
>> 
>> Pascal
>> 
>> 
>> 
>> -----Original Message-----
>> From: 6lo [mailto:[email protected]] On Behalf Of Tim Chown
>> Sent: vendredi 16 février 2018 20:03
>> To: [email protected]
>> Cc: [email protected]; [email protected]
>> Subject: [6lo] Intdir early review of draft-ietf-6lo-rfc6775-update-11
>> 
>> Reviewer: Tim Chown
>> Review result: Almost Ready
>> 
>> Hi,
>> 
>> I have performed an early review of draft-ietf-6lo-rfc6775-update-11.
>> 
>> This draft updates and enhances the mechanisms defined in RFC6775 to 
>> support
>> IPv6 operation over low power networks (6LoWPAN ND).
>> 
>> Overall the draft is well-written and structured.
>> 
>> General comments:
>> --------------------------------------
>> 
>> The document could use a glossary of terms: LLN, 6LN, 6LBR, 6LR, BBR, etc.
>> 
>> The introduction could talk of other new added features, like avoiding 
>> DAD for link locals.
>> 
>> The document includes RFC 7217 in the references, but doesn't include 
>> discussion of it in the main body of the text.  Shouldn't RFC 7217 be 
>> considered the norm here rather than address generation as per RFC 4862?
>> Related, RFC 8064 "recommends against embedding stable link-layer 
>> addresses in
>> IPv6 Interface Identifiers".  The document is inconsistent - it talks 
>> of using EUI64, then in Section 9 not using EUI64.
>> 
>> Specific comments:
>> --------------------------------------
>> 
>> p.3
>> Section 2, para 2 - should ND cache exhaustion attacks be included in 
>> the list here?
>> 
>> p.4
>> Section 3 - Add RFC 7217 to RFC 4862?  It's recommended by RFC 8064.
>> 
>> p.6
>> Section 4 - for a node to prefer registering to a 6LR that supports 
>> the spec, it would need to enumerate all available 6LRs; should the 
>> process for this be described here, or is it included in sufficient detail 
>> in RFC 6775?
>> 
>> p.7
>> Section 4.1 - "not required to be a MAC address" - as per my general 
>> comment above, with current IETF thinking, should this not be 
>> stronger, e.g. "SHOULD NOT be a MAC address"?  Section 9 says this?
>> 
>> p.9
>> Section 4.2, point 4 - I find this quite para quite hard to read.
>> 
>> p.9
>> Section 4.3, para 1 - again, is using EUI-64 desirable?  Is the point 
>> to allow header compression as per RFC4944?  Discuss the tradeoff? 
>> Section 4.3 para 2 - so a different type of identifier could be an RFC 7217 
>> generated identifier?
>> 
>> p.11
>> Section 4.6 - in the case of two 6LRs with the same link-layer 
>> addresses, does it matter which a 6LN chooses?  Is the choice 
>> algorithmic? Section 4.6 - the last para on p.11 seems to be repeated in the 
>> first para on p.12?
>> 
>> p.12
>> Section 4.6 - again, is the recommendation to use an (expected to be) 
>> unique LL address in keeping with RFC 8064?
>> 
>> p.13
>> Para 4 - a Moved message SHOULD be used, yet elsewhere a node MUST 
>> clean up its stale state?  Consistent? What about MIPv6-like spoofing 
>> security issues? You say "an alternate protocol" - isn't this a little 
>> hand-wavy; shouldn't a single mechanism be defined rather than multiple 
>> (undefined) mechanisms?
>> 
>> p.15
>> OUI is a confusing choice of term, given OUIs in MAC addresses; I 
>> guess this is now baked into RFC 6775 though.
>> 
>> p.16
>> I don't think codes 5 and 10 are explained/defined in any detail here?  
>> How is the challenge made?
>> 
>> p.16
>> The registration lifetime is in minutes; why not in seconds?
>> 
>> p.18
>> Section 6.3 - SHOULD set the E flag; why not a MUST?  Why would you 
>> support the spec, but not advertise that you do?  In contrast, on the 
>> next page in Section
>> 7.1.1 you say nodes MUST set it.
>> 
>> p.19
>> Section 7.1.2 para 2 - would a LL address generally be used here as source? 
>> Should that be a SHOULD?  Using a temporary address is probably not ideal.
>> 
>> p.20
>> Section 7.3 para 4 - is this consistent with p.19 last para saying a 
>> 6LN MUST use the updated spec once it knows it's supported? The last 
>> two paras here are a bit vague/loose.
>> 
>> p.21
>> Section 8, para 3 - recommends using privacy techniques, but uses EUI64?
>> 
>> p.22
>> Limit the number of addresses?  What about RFC 7934?
>> The type of algorithm described here might be better defined 
>> generically for 6LoWPAN and 'real' IPv6?  I don't think anything has 
>> been defined for ND cache exhaustion attack mitigation - would a 
>> separate draft be beneficial? I suspect current solutions are vendor 
>> specific?
>> 
>> p.22
>> What trust model?
>> 
>> p.22
>> Section 9 - EUI64, or not EUI64?  Inconsistent.
>> Does anyone really use SeND?  Especially in 6LoWPAN networks?
>> 
>> p.24
>> Section 10.3 - statuses 5 and 10 are not detailed in the draft?
>> 
>> p.30
>> The multicast issues text could cite the new mboned draft on this topic.
>> "Plague" is maybe strong!
>> 
>> p.30
>> Appendix B - can we have a table showing WHICH requirements have been 
>> met by the draft?
>> 
>> Nits:
>> --------------------------------------
>> 
>> p.4
>> Section 2 - "form and use multiple addresses" (add multiple)
>> 
>> p.4
>> Section 2 last para - "their" rather than "his"
>> 
>> p.6
>> "provides new" -> "provide new"
>> 
>> p.10
>> "route-over mesh" - add to definitions section
>> 
>> p.12
>> First line of last para needs rewriting - "If the registry in the 6LBR 
>> is be saturated, in which case the LBR".
>> 
>> p.13
>> Could forward reference the summary of error codes in 6.1 or 10.3 here?
>> 
>> p.14
>> "removes silently" -> "silently removes"
>> "LLNs meshes" -> "LLN meshes"
>> 
>> p.15
>> Code 3; change tense to past tense, e.g. "fails" to "failed"
>> 
>> p.19
>> "capabilities" -> "capabilities is"
>> "such address" -> "such an address"
>> "in a" -> "in"
>> "6LB" -> "6LN" ?
>> 
>> p.21
>> "amlways" -> "always"
>> "to using" -> "using"
>> Missing close bracket for See Section 9.
>> 
>> p.30
>> Do you mean "sequence"?
>> "serves" -> "serves the"
>> 
>> p.31
>> "timely" -> "in a timely fashion" ?
>> B.1 last req - reword this.
>> The BIER Architecture is now an RFC I think?
>> 
>> 
>> _______________________________________________
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>> https://www.ietf.org/mailman/listinfo/6lo
>> 
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