Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds

Ted Lemon <mellon@fugue.com> Wed, 30 October 2019 11:19 UTC

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From: Ted Lemon <mellon@fugue.com>
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Date: Wed, 30 Oct 2019 07:19:22 -0400
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Cc: Philip Homburg <pch-v6ops-9@u-1.phicoh.com>, v6ops@ietf.org
To: Ole Troan <otroan@employees.org>
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Subject: Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds
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On Oct 30, 2019, at 7:01 AM, Ole Troan <otroan@employees.org> wrote:
> 
> What a CPE does do, is to send an ICMP destination unreachable (5 - Source address failed ingress/egress policy) as the source address would violate the unicast RPC check. RFC7084, L-14.

Does this actually happen in practice, though?

It’s not actually clear to me how L-13 would be implemented.   Is a failure to provide a prefix that’s been requested an indication that the prefix is no longer valid, or simply that it isn’t renewed?   Should the CPE in this case stop using it?   What does “replaced by” actually mean?

From the perspective of DHCP PD, it would be valid for the CPE to continue using the prefix until it expires.   That might very well not be the right thing to do, but there is a lack of clarity here in the specification, and I am wondering how router vendors have interpreted this in practice.