Re: [v6ops] Interesting problems with using IPv6

Fernando Gont <fgont@si6networks.com> Wed, 10 September 2014 01:13 UTC

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Date: Tue, 09 Sep 2014 21:47:37 -0300
From: Fernando Gont <fgont@si6networks.com>
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To: Brian E Carpenter <brian.e.carpenter@gmail.com>, Brian Haberman <brian@innovationslab.net>
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Subject: Re: [v6ops] Interesting problems with using IPv6
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On 09/09/2014 05:40 PM, Brian E Carpenter wrote:
>>> Then, let me change the question: Why do I need MLD for *this*?
> 
> I think Brian Haberman's reply shows why that is the wrong question.
> You need MLD for every multicast group, including a solicited-node
> group, and if you insist on MLD snooping in the bridges (let's not
> obfuscate by calling them switches) then you need to snoop every
> solicited-node group.
> 
> My question is orthogonal to MLD snooping: why do we require router-alert
> for MLD messages referring to a solicited-node group, since it by
> definition is limited to a single L2 link (even if that link is
> split up by bridges)?

.. to avoid them being a special case?  -- i.e., all MLD packets carry a
Router Alert option. And, actually, an MLD report could potentially
include groups other than solicited-node (so you probably wouldn't want
to turn the "include a router-alert" on and off).

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: fgont@si6networks.com
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