Re: [Roll] MPL draft 2

peter van der Stok <stokcons@xs4all.nl> Wed, 31 October 2012 09:55 UTC

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Date: Wed, 31 Oct 2012 10:55:06 +0100
From: peter van der Stok <stokcons@xs4all.nl>
To: "Jonathan Hui (johui)" <johui@cisco.com>
Organization: vanderstok consultancy
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Cc: richard kelsey <richard.kelsey@silabs.com>, roll@ietf.org
Subject: Re: [Roll] MPL draft 2
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Reply-To: consultancy@vanderstok.org

Hi Jonathan,

I'm afraid I misunderstood the domain concept, and we do not consider 
the same case
Possibly my case is too specific, but let me explain in different words 
with an example.

Two border routers are connected to two 802.15.4 networks, N1 and N2. 
The nodes of N1 have a different unicast prefix from the nodes of N2.
The nodes of N1 receive packets with link-local addresses coming from 
nodes of N2 and vice versa because the groups are closely spaced.
A node A1 in group N1 wants to send a multicast to a group G1 of nodes 
in N1.
The group members of G1 share a Unicast prefix multicast address with 
the unicast prefix belonging to group N1 nodes.
Node A1 uses this MC address when sending a message.
To my current understanding, MPL passes the message without 
encapsulation on to all forwarders in networks N1 and N2.
My hope was to limit the reception to forwarders in group N1 only.
That suggests a filter at reception on the unicast prefix, when the 
multicast address is a unicast prefix multicast address.

Does this still merit the same answer?

Peter

Jonathan Hui (johui) schreef op 2012-10-30 18:21:
> Hi Peter,
>
> If I understand correctly, you would like to configure MPL multicast
> scope zones by having MPL forwarding interfaces subscribe to 
> different
> IPv6 multicast addresses.  That is fine with me, but only works when
> using IPv6-in-IPv6 encapsulation.  If you want to limit the scope of
> MPL multicast packets that do not use IPv6-in-IPv6 encapsulation, we
> can't rely on the IPv6 Destination Address since that is set by the
> source of the original multicast packet.
>
> Thoughts?
>
> --
> Jonathan Hui
>
> On Oct 22, 2012, at 6:53 AM, peter van der Stok <stokcons@xs4all.nl> 
> wrote:
>
>> Hi Jonathan and Richard,
>>
>> thanks for the new MPL draft. During a first reading I had some 
>> problems with the domain concept.
>> I understood that a domain may be composed of several link-local 
>> scopes.
>> When configuring an interface with one link-local scope I should 
>> like to reject link-local multicasts which come from link-local 
>> neigbors that do not belong to the domain for which the interface is 
>> configured. For example: closely spaced wireless nodes which have 
>> different edge routers. To express the domain in the multicast address 
>> were you thinking of "transient" and "unicast prefix based" mc 
>> addresses with format ff32::prefix:group?. Configuring the interface 
>> with a link-local scope limited to one prefix may cover the domain 
>> concept adequately.
>>
>> In my opinion some text on interface configuration to implement 
>> packet rejection based on Mc domain will be useful.
>>
>> Greetings
>>
>> Peter
>>
>> --
>> Peter van der Stok
>> mailto: consultancy@vanderstok.org
>> www: www.vanderstok.org
>> tel NL: +31(0)492474673     F: +33(0)966015248

[Roll] MPL draft 2 peter van der Stok
Re: [Roll] MPL draft 2 Jonathan Hui (johui)
Re: [Roll] MPL draft 2 peter van der Stok