Re: [dhcwg] dhcpv6-24: use of anycast

Ole Troan <> Wed, 08 May 2002 15:49 UTC

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To: Thomas Narten <>
Cc: Ralph Droms <>,
Subject: Re: [dhcwg] dhcpv6-24: use of anycast
References: <>
From: Ole Troan <>
Date: Wed, 08 May 2002 16:46:17 +0100
In-Reply-To: <> (Thomas Narten's message of "Wed, 08 May 2002 11:31:12 -0400")
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>> Thomas - the use of anycast is to allow the use of DHCP on links
>> that do not support multicast.  The intention is to use anycast just
>> across the link to which the client is attached; a relay agent
>> forward messages across the rest of the path to the server.
> OK. It was not clear to me that anycast was restricted to the first
> hop.
> But... If a link doesn't support IPv6 multicast, how will it support
> Neighbor Discovery? I suspect there are only a few links that might
> have this property. Do we understand what those link types are and
> whether its important that DHC run over them?
>> If all IPv6 links support multicast, then we don't need the anycast address
>> for DHCP.
> This would be my assumption. Do folks have examples of link types they
> are concerned about?

ATM, Frame Relay RFC2491), ISDN/PSTN, MPLS, 6to4, ISATAP.  if routers
use DHCP (e.g Prefix Delegation) then support is needed for the first
set of media. hosts connecting through an ISATAP cloud could very well
need DHCP I should think.


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