Re: [ipwave] [Int-dir] Intdir early review of draft-ietf-ipwave-ipv6-over-80211ocb-34 - 'conforming IPv6' - fe80::/10 vs fe80::/64

[Ole Troan <[e-mail]>]

Alexandre,

Right, so it doesn’t sound like you have any reason to be different from RFC2464.
Just reference or copy that text (section 5, rfc2464).

Ole

> On 10 Apr 2019, at 11:22, Alexandre Petrescu <[e-mail]> wrote:
> 
> 
> 
> Le 10/04/2019 à 11:04, Ole Troan a écrit :
>>>>>> "At least" does not mean "the value should be at least 10" in that phrase.
>>>>>> 
>>>>>> Do you think we should say otherwise?
>>>>> 
>>>>> To me there is nothing in the actual text to tell me that "at least"
>>>>> qualifies the "/10". I think you could rephrase as
>>>>> "This subnet's prefix MUST lie within the link-local prefix fe80::/10 ..."
>>>>> 
>>>>> However, see Jinmei's messages about conformance with RFC 4291.
>>>>> 
>>>>> I think there might be unexpected side effects from using an
>>>>> address like fe80:1::1. What if some code uses matching with
>>>>> fe80::/64 to test if an address is link-local? I agree that
>>>>> would be faulty code, but you would be the first to discover it.
>>>> Indeed.
>>>> If you absoultely must cut and paste text from 2464:
>>> 
>>> YEs, that is how we started.  We cut and paste from 2464.
>>> 
>>>> 5.  Link-Local Addresses
>>>>    The IPv6 link-local address [AARCH] for an Ethernet interface is
>>>>    formed by appending the Interface Identifier, as defined above, to
>>>>    the prefix FE80::/64.
>>>>        10 bits            54 bits                  64 bits
>>>>      +----------+-----------------------+----------------------------+
>>>>      |1111111010|         (zeros)       |    Interface Identifier    |
>>>>      +----------+-----------------------+----------------------------+
> >>>
>>>> I presume there is support for bridging 802.11p and other 802.3 links?
> 
> In the IP-OBUs that I know there is IP forwarding between 802.11-OCB (earlier 802.11p) and 802.3, not bridging.
> 
> In some IP-OBU (Internet Protocol On-Board Unit) some non-OCB interfaces are indeed bridged.  E.g. the Ethernet interface is bridged to the WiFi interface; that helps with DHCP, tcpdump and others to see one a single - bridged - interface.
> 
> Bridging may be, but it is not a MUST.  There is no necessarily any bridging between the 802.11-OCB interface and other interface, neither bridging between the multiple 802.11-OCB interfaces that might be present in the same computer.
> 
> Do you assume bridging of 802.11-OCB interface to Ethernet interface is always there?
> 
> Note: I also heard many comments suggesting that EAL is akin to 'bridging'.  I do not know whether you refer to that perspective.  If yes, we can discuss it separately.
> 
> Alex
> 
> [...]
> 
>>>> And that the MAC address length of this link type is also 48 bits?
>>> 
>>> YEs, the length of MAC address on 802.11 mode OCB is also 48.
>>> 
>>>> If the two assumptions above hold, then I see zero justification for pushing the 64 bit boundary in this draft.
>>> 
>>> Let me try  to understand the first assumption.
>> Ole
> 
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