Re: [v6ops] DAD again [was: draft-ietf-v6ops-host-addr-availability discussion]

"Hemant Singh (shemant)" <shemant@cisco.com> Fri, 13 November 2015 19:36 UTC

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From: "Hemant Singh (shemant)" <shemant@cisco.com>
To: Owen DeLong <owen@delong.com>
Thread-Topic: [v6ops] DAD again [was: draft-ietf-v6ops-host-addr-availability discussion]
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Date: Fri, 13 Nov 2015 19:36:21 +0000
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Cc: "v6ops@ietf.org" <v6ops@ietf.org>
Subject: Re: [v6ops] DAD again [was: draft-ietf-v6ops-host-addr-availability discussion]
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-----Original Message-----
From: Owen DeLong [mailto:owen@delong.com] 
Sent: Friday, November 13, 2015 12:43 PM
To: Hemant Singh (shemant)
Cc: Alexandre Petrescu; v6ops@ietf.org
Subject: Re: [v6ops] DAD again [was: draft-ietf-v6ops-host-addr-availability discussion]

>How is it possible to have a duplicate address on a loopback interface?

A router configures a loopback interface and provisions an IPv6 address on the interface.  The is a LAN in the router downstream port which the router destines packets to using the source as the IPv6 address on the loopback.  The LAN segment may have a duplicate unless the loopback IPv6 address is disjoint from any IPv6 prefix on the router and router LAN/WAN segment.   Another use case is already mentioned in this thread - two routers directly connected.

Hemant