Re: [16NG] Re: multicast and IPv6 over ETHCS

[Alexandru Petrescu <alexandru.petrescu at motorola.com>]

Hi Max,

Let me try to understand this.  You suggest that it is the aim of the
draft to specify the link layer behaviour when forwarding IPv6 multicast
messages.  I suggest that no link-layer behaviour should be specified,
but the interface.  (a distinction akin to OO programming, but
may not be that obvious).  I think we  may be saying the same thing but
with different words.

So, in order to clarify whether we agree or not: do you agree with the
multicast text I've sent, see below?   Do you think that text has its
place in the draft?

Thanks,

Alex

Riegel, Maximilian wrote:
> Hi Alex,
>
> I do not agree with your proposal. It is the aim of the draft to 
> specify the particular behavior of the link layer when forwarding 
> IPv6 multicast messages.
>
> The IPv6 solution does not relay on the multicast implementation in 
> the ETH link layer, but specifies what should be provided in the ETH 
> link layer to more efficiently handle IPv6 multicast messages over 
> IEEE802.16.
>
> Bye Max

[snipping the rest of thread and inserting the multicast for IPv6 on
 ETHCS proposal text]

> Running IPv6 over an Ethernet link needs the support of link-layer 
> multicast. In the 802.16 context, the Ethernet Convergence Sublayer 
> (also known as the IEEE Std 802.3/Ethernet-specific part of the IEEE
>  802.16 Packet Convergence Sublayer) must (1) support multicast 
> link-layer addresses (2) map IPv6 multicast addresses to link-layer 
> addresses and vice-versa, (3) offer the capability of joining and 
> leaving IPv6 link-local multicast groups and (4) send and receive 
> IPv6 link-local multicast packets whose link-layer headers contain 
> link-layer multicast addresses.
>
> The following link-layer multicast addresses are recommended by 
> RFCXXXX: 33:33:0:0:0:1, 2, 33:33:ff:XX:XX:XX, and others [fill].
>
> The rules for mapping IPv6 link-local multicast addresses to 
> link-layer multicast addresses are recommended by RFCxxxx and are the
>  following: - ff02::1 maps into 33:33:00:00:00:1 - and the others.
>
>
> The IPv6 stack must join a certain link-local IPv6 multicast group 
> before receiving packets addressed to that group. For example, before
>  receiving a Router Advertisement the stack MUST join the IPv6 
> link-local multicast address 'all-nodes'. When the IPv6 stack on the
>  Subscriber Station joins a certain IPv6 link-local multicast group
> it MUST receive all packets addressed to that group. The join
> operation can happen in several ways: sending a MLD REPORT (RFCxxx),
> setting a local filtering rule, etc.
>
> The IPv6 stack must be able to leave a certain IPv6 link-local 
> multicast group. When the IPv6 stack leaves a group must no longer 
> receive the IPv6 packets addressed to that group. Similarly to the 
> joining operation the leaving operation can happen in several ways: 
> sending a MLD REPORT, setting a local filtering rule, etc.
>
> The following Neighbour Discovery messages are sent by a Subscriber 
> Station to IPv6 link-local multicast addresses: Neighbour 
> Advertisement, Neighbour Solicitation, Router Solicitation (RFCxxxx).
>  The following Neighbour Discovery messages are received by a 
> Subscriber Station, addressed to IPv6 link-local multicast addresses:
>  Router Advertisement, Neighbour Advertisement, Neighbour 
> Solicitation.

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