Re: MLDv1 still in the wild?

On 2/29/2012 1:17 PM, Behcet Sarikaya wrote:
> On Wed, Feb 29, 2012 at 2:42 PM, Fernando Gont<fgont@si6networks.com>  wrote:
>> On 02/29/2012 11:38 AM, Simon Perreault wrote:
>>> On 2012-02-28 08:12, Jeroen Massar wrote:
>>>> I was wondering, if anybody had a rough idea how many MLDv1-only
>>>> listeners are still out there in the wild. My assumption by now is that
>>>> current code out there (thus not stuff that has been up and running and
>>>> never upgraded for the last 5 years orso ;) all supports MLDv2... or is
>>>> there a major platform which does not do MLDv2?
>>>
>>> On the open-source side, I know of OpenBSD and NetBSD which are still
>>> MLDv1 only.
>>
>> Even if they implemented MLDv2, I'd argue that the default should
>> probably be MLDv1 rather than MLDv2: unless non-local multicast is
>> employed, MLDv2 is unnecessarily complex if it's just for the purpose of
>> ND and the like.
>
> This is true.

I think the main reason OpenBSD and NetBSD don't support SSM is
Apple's IPR claim. Without SSM support, there is little reason to
support MLDv2.

I'm a bit curious about the reason for the question. At least MLDv2
routers are supposed to support MLDv1 compatibility mode.

> However, RFC 5790, on Lightweight IGMP/MLD makes it easy to support
> SSM. I think there is open source support for 5790 somewhere.

What it does is basically removing exclude mode for a non-empty
source list. It is still a lot of work compared to IGMPv2/MLDv1.
Apart from hosts in general, I can imagine a lot of special purpose
devices that never needs SSM to only implement MLDv1.

Stig

> Behcet
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