[dhcwg] Mail regarding draft-ietf-dhc-dhcpv6-prefix-length-hint-issue

"Bernie Volz (volz)" <volz@cisco.com> Mon, 25 July 2016 12:47 UTC

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From: "Bernie Volz (volz)" <volz@cisco.com>
To: "draft-ietf-dhc-dhcpv6-prefix-length-hint-issue@ietf.org" <draft-ietf-dhc-dhcpv6-prefix-length-hint-issue@ietf.org>
Thread-Topic: Mail regarding draft-ietf-dhc-dhcpv6-prefix-length-hint-issue
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Date: Mon, 25 Jul 2016 12:47:51 +0000
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Subject: [dhcwg] Mail regarding draft-ietf-dhc-dhcpv6-prefix-length-hint-issue
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Here's some comments related to the draft-ietf-dhc-dhcpv6-prefix-length-hint-issue-02 version.

Section 1:

-          "as it just help a client" -> change help to helps?

-          Same area, perhaps mention that 3315bis is dropping use of the lifetime hints?

-          Later - "handle the prefixes which lengths are different" - "handle prefixes with lengths different from the prefix-length hint"?

I wonder whether a "general solution" section should be added which says something like:

"Therefore, the recommendation to address the issues discussed in this document, is for a client that wants (at least) to have a delegated prefix of a specific prefix length to always include an IAPREFIX option with just the prefix length hint in addition to any IAPREFIX options it has included for each IA_PD in any Solicit, Request, Renew, and Rebind messages it sends. While a server is free to ignore the hint, servers that do not choose to ignore the hint should attempt to assign a prefix of at least the hint length (or shorter) if one is available. Whether a server favors the hint or avoiding a renumbering event is a matter of policy for the server."

Note that this could actually be taken as one way to interpret the original RFC 3633 text, which said:

   The requesting router may include prefixes in the IA_PDs as a hint to
   the delegating router about specific prefixes for which the
   requesting router has a preference.

This text was as part of the Solicit discussion, but perhaps it was intended to apply to subsequent transactions as well (Request, Renew, Rebind).

-          Bernie