Re: [v6ops] Interesting problems with using IPv6

Fernando Gont <fgont@si6networks.com> Wed, 10 September 2014 08:09 UTC

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Date: Wed, 10 Sep 2014 03:52:46 -0300
From: Fernando Gont <fgont@si6networks.com>
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To: Brian E Carpenter <brian.e.carpenter@gmail.com>
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Subject: Re: [v6ops] Interesting problems with using IPv6
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Hi, Brian,

On 09/09/2014 11:16 PM, Brian E Carpenter wrote:
> On 10/09/2014 12:47, Fernando Gont wrote:
>> 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. 
> 
> Yes, it would be an exception. But we know that HbH options in general
> and Router Alert in particular are a serious performance issue, and
> that all links carry this particular kind of MLD traffic, so an
> exception seems like something to be discussed.

Agreed.

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