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Dear DNA WG
This is an attempt to resolve this issue: Issue 3 Jim Bound proposed to remove Sub-sec 3.2. Inadequacies in RA information Suggested resolution At San Diego meeting, WG agreed to remove Sub-sec 3.2, so we
reduced
Sub-sec 3.2 to just present the difficulty for a single RA message to indicate a link change. We propose to change Sub-sec 3.2 (after we remove Sec 2, this will be Sub-sec 2.2) as below.
3.2 Link identity detection with a single
RA
Usually a host gets the information necessary for IP
configuration
from RA messages. Based on the current definition [ND], it's difficult for a host to check for link change upon a single RA reception. To detect link identity, a host may compare the informations
in an RA,
for example router address or prefixes, with the existing ones. The host may use a router address to check for link change.
But the
router address in the source address field of an RA is link-local scope, so its uniqueness is not guaranteed out side of a link. So if it happens that two different router interfaces have the same link-local address, the host can't detect that it has moved from one interface to another by checking the router address in RA messages. Or the host may check whether an incoming RA includes the
currently
stored prefix. But an unsolicited RA message can omit some prefixes for convenience [4]. Hence, the host can't be sure that the existing prefix is not supported on the currently attached link, even though the prefix is not contained in a received RA. The set of all the global prefixes assigned to a link can
represent a link
identity. But it's not easy for a host to attain and retain all the prefixes with certainty, so the prefix list based DNA scheme needs further investigation [CPL]. Please register your opinion if you have any comments,
otherwise
we'll update the goals draft accordingly and move it forward. Thanks to Greg's kind work, we now have the issue list at http://ctieware.eng.monash.edu.au/twiki/bin/view/DNA/DNAGoals Thanks for your kind consideration. Best Regards JinHyeock |