Re: WG ACTION: 2 weeks to discuss [LL56] Contradictory text?

I understand the issue but can't comment until the "Requested Change" is 
specified.

- Ralph

At 12:59 AM 5/5/2004 +0200, Erik Guttman wrote:
>Please post discussion of this issue to the mailing list over the next two 
>weeks
>ending May 18, 2004.  In order to accept this issued, we will need a strong WG
>consensus given that this is very late in the process.
>
>Please see http://www.drizzle.org/~aboba/ZEROCONF/issues.html for a list of
>current issues and their status.
>
>[LL56]
>
>Description of Issue:           Contradictory text?
>Submitter Name:                 Stuart Cheshire
>Submitter Email Address:        [email protected]
>Date first submitted:           04 May 04
>Reference:
>Comment Type ['t'ech|'e'dit]:   t
>Prio ['S' Must|1 should|2 may]: S
>Section:                        1.4, 1.8
>Rationale/Explanation:
>Lengthy Description:
>
>[Stuart]
>
>>         IPv4 addresses ...
>>       ... which can only be resolved on the local link ...
>>       ... SHOULD only be sent when a Link-Local address
>>       is used as the source address.
>
>Sent how? In the header? In the payload? Doesn't this contradict the text
>later in the document that says:
>
>>    There will be cases when devices with a configured Link-Local address
>>    will need to communicate with a device with a routable address
>>    configured on the same physical link, and vice versa.  The rules in
>>    Section 2.6  allow this communication.
>
>This says that link-local addresses *can* be used when the source address
>is *not* link-local.
>
>[Erik]
>
>The IPv4 address would be sent in the LLMNR (DNS) payload.  I though
>that was obvious due the the context in the paragraph.
>
>The first paragraph refers to text in section 1.4.b which discuss
>limitations of the use of IPv4 LL when used with LLMNR.  The second
>paragraph is in section 1.8 which discusses general communication
>between two hosts.  In the latter case, the text is definitely
>appropriate.
>
>I believe there is no contradiction.  1.4.b does not hinder the use of
>LLMNR or IPv4 LL configuration except in one case:  A host implementor
>is admonished (using SHOULD) to only hand out a LL address using LLMNR
>when the host has a LL configuration and only from an interface which in
>fact has been configured with an LL adddress.
>
>[Stuart]
>
>I disagee.
>
>As stated, a device with a routable address, and a link-local-scope name
>of some kind, is prohibited from answering queries for that name, because
>the name can only be resolved on the local link, but the device doesn't
>have a Link-Local address to use as the source IP address.
>
>[Erik]
>
>  The full quote is:
>
>       IPv4 addresses and names which can only be resolved on the local
>       link SHOULD NOT be forwarded, they SHOULD only be sent when a
>       Link-Local address is used as the source address.  This strong
>       advice should hinder limited scope addresses and names from
>       leaving the context in which they apply.
>
>     There is no prohibition.  There is only a 'SHOULD' implying that
>     this is not a great idea.  The issue of 'leaving the context ni
>     which they apply' is not very serious *today* since LLMNR has only
>     LL scope.  In the future, LLMNR might be admin scope MNR.  In this
>     case, we will need the SHOULD above - so that link-local scope
>     identifiers (addresses and names) are properly contained.
>
>Requested Change:
>
>TEXT NEEDED