On Wed, Feb 18, 2009 at 12:27 AM, Alexandru Petrescu
<[email protected]> wrote:
> Hamid Mukhtar a écrit :
>>
>> On Mon, Feb 16, 2009 at 11:51 PM, Alexandru Petrescu
>> <[email protected]> wrote:
>>>
>>> [I cut ROLL from the distribution list, because it seems I post too much
>>>  on the ROLL list]
>>>
>>> Thanks for the message.  I mainly agree with you.  I commented on some of
>>> the text, below.
>>>
>>> Eunsook "Eunah" Kim a écrit :
>>> [...]
>>>>>
>>>>> Some high-level questions:
>>>>> -is there a requirement to connect a 6LoWPAN network to the Internet?
>>>>
>>>> Do you mean in terms of routing? Or a general view of 6LoWPAN?
>>>> The birth of 6LoWPAN is to make the Low-power low rate network (based
>>>> on IEEE 802.15.4) look like an IPv6 link.
>>>>
>>>> If you only meant routing, the reachability can be achieved by mesh
>>>> routing (or mesh switching in your comment below) or route-over.
>>>>
>>>> I don't know if it answers your question.
>>>
>>> If a network running 6LoWPAN routing system (designed according to
>>> 6lowpan-routing-requirements) is connected to the Internet - will anything
>>> break?
>>>
>>>>> -is the 6LoWPAN using addressing architecture and longest-prefix match
>>>>>  based routing as in the Internet?
>>>>
>>>> Alex, I think RFC 4944 may help your curiosity of 6lowpan fundamental.
>>>>
>>>> Although the header compression format is updating in 6lowpan now, you
>>>> can find a basic needs of 6lowpan in the RFC.
>>>> If I shortly explain, an IPv6 Interface Identifier is obtained from
>>>> the 64-bit or 16-bit IEEE 802.15.4 address. The IPv6 link-local
>>>> address for an IEEE 802.15.4 interface is formed by appending the
>>>> Interface Identifier to a certain prefix (see Section 6 and Section 7
>>>> of RFC 4944). With regard to routing, I understand the answer is 'yes'
>>>> in the case of route-over.
>>>> Please kindly let me know if you already checked the RFC and your
>>>> intention from the question was different from my answer. :)
>>>
>>> Yes, thanks for posting rfc4944, I checked it.
>>>
>>> Will the 6LoWPAN router use longest-prefix match (as IP protocols do) or
>>> exact-match (as some VLAN switch protocols do).
>>>
>>> Will the 6LoWPAN addressing architecture be local to the network, or
>>> integrated in the Internet.
>>
>>
>> RFC4944's HC1 supports both link-local and global addressing i.e. all
>> 128 bits can be carried inline or the elided suffix can be derived
>> from lower-layers.
>>
>> The new HC scheme also supports both types of addressing.
>
> I have no doubts the header compression scheme can accommodate both global
> and link-local addresses.
>
> By 'local' I meant also Unique Local IPv6 Unicast Addresses (rfc4193).
>
> The discussion was around how is the IPv6 addressing architecture designed
> for a 6LoWPAN network.
>

For the 6LoWPAN side the IIDs are derived from the lower-layers. As
per my understanding of 6LoWPAN, the Unique Local Addresses (ULAs) are
not utilised for local communication i.e. for local communication the
addresses are link-local addresses with prefix elided. However, for
communication with nodes outside 6LoWPAN the 6LoWPAN node's prefix can
either be a global prefix or a ULA's prefix.

>>> How is a link-local scoped solicited node multicast address mapped into
>>> an 802.15.4 address?
>>>
>>> rfc4944 says rightmost 2 bytes go into a 802.15.4 16-bit multicast
>>> address.
>>>
>>> But rfc4291 says a solicited node multicast address has the rightmost 3
>>> octets as significant (FF02:0:0:0:0:1:FFXX:XXXX).
>>>
>>> Will NS/NA and DAD work ok on these links?
>>>
>>
>> The new HC format can handle this scenario
>> http://tools.ietf.org/html/draft-ietf-6lowpan-hc
>>
>> it supports compression of the Solicited-Node Multicast Address
>> (FF02::1:FFXX:XXXX).
>
> Ok, thanks for the message, I will check the HC draft.
>
> Alex
>
>
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Regards,
Hamid
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