Re: Question on anycast IID range(s)

Thanks Erik,

My question was ill-posed *and* contained a typo.  I'm really trying to
figure out
which range(s) of IIDs RFC 2526 is trying to reserve for anycast use.  I
now think
the answer is fdff:ffff:ffff:ff80-fdff:ffff:ffff:ffff based on RFC 5453 and
https://www.iana.org/assignments/ipv6-interface-ids/ipv6-interface-ids.xhtml
.

Regards, Kerry

On Wed, Jan 2, 2019 at 12:57 PM Erik Kline <ek@loon.co> wrote:

> I think practically speaking the only to tell if an address on another
> node is anycast or not is by the observable difference in the NA:
>
>     https://tools.ietf.org/html/rfc4861#section-7.2.7
>
> """
>    From the perspective of Neighbor Discovery, anycast addresses are
>    treated just like unicast addresses in most cases.  Because an
>    anycast address is syntactically the same as a unicast address, nodes
>    performing address resolution or Neighbor Unreachability Detection on
>    an anycast address treat it as if it were a unicast address.  No
>    special processing takes place.
>
>    Nodes that have an anycast address assigned to an interface treat
>    them exactly the same as if they were unicast addresses with two
>    exceptions.  First, Neighbor Advertisements sent in response to a
>    Neighbor Solicitation SHOULD be delayed by a random time between 0
>    and MAX_ANYCAST_DELAY_TIME to reduce the probability of network
>    congestion.  Second, the Override flag in Neighbor Advertisements
>    SHOULD be set to 0, so that when multiple advertisements are
>    received, the first received advertisement is used rather than the
>    most recently received advertisement.
> """
>
>
> On Wed, 2 Jan 2019 at 08:51, Kerry Lynn <kerlyn@ieee.org> wrote:
>
>> For practical purposes, particularly in light of RFC 7136, should one
>> consider an anycast address to be any that ends in dfff:ffff:ffff:ff80-
>> dfff:ffff:ffff:ffff OR ffff:ffff:ffff:ff80-ffff:ffff:ffff:ffff?
>>
>> The phrase in RFC 2526 that's causing confusion for me is
>> "Specifically, for IPv6 address types required to have to have
>> [sic] 64-bit interface identifiers in EUI-64 format ..."  To my
>> knowledge, there are address types that require a 64-bit IID,
>> but it seems we've been systematically trying to deprecate
>> *EUI-64 format* IIDs.  In any case, there's nothing to prevent a
>> mix of EUI-64 or *other* format IIDs in the same subnet as far
>> as I'm aware.
>>
>> Thanks, Kerry
>>
>> --------------------------------------------------------------------
>> IETF IPv6 working group mailing list
>> ipv6@ietf.org
>> Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
>> --------------------------------------------------------------------
>>
>