RE: When IBoE will be merged to upstream?

Liran Liss
2010-07-15T11:14:16Z

> > A quibble about multicast - AFAIK this is unsolved. I
> think some spec > needs to be agreed that documents what
> sort of multicast snooping > operations switches need to do,
> ie if IGMP joins imply that IBoE > traffic for the same DMAC
> is included in the join, or if IBoE requires > a seperate
> IGMP type process on its own ether-type. That would make it
> > much clearer what to do with MGIDs.
>

It would be quite naïve to require *new* snooping functionality in Eth switches. Some switches will gracefully apply to non-ip traffic the filtering information acquired through IGMP snooping. And some will just flood non-ip MC frames within the corresponding VLAN which is benign (e.g. that is the way FIP works). A cleaner solution would be based on MMRP but that, AFAIK, is not very widely deployed so it is less practical at this stage.

> I agree -- the current spec is rather broken for multicast.
> Choosing a different ethertype and then saying that all
> switches will just flood multicast traffic is half-baked at best.
>

It is a realistic approach. Do you claim that there are switches that will not forward the packets?

> > It would be nice to at least have a plan on how to
> integrate a > non-link local address, if that is ever
> necessary in future. An > extended AH with an additional 48
> DMAC field seems reasonable to me?
>
> You mean have a next-hop destination + a final destination?
> Could be done I guess. But I'm not sure how having a routing
> table where you have to look up 48-bit Ethernet addresses is
> all that different from just having a standard Ethernet
> forwarding table.

I guess Jason suggests regarding the GID as a true L3 address and using a new added L2 field for the next hop L2 address.

>
> I suppose something based on MAC-in-MAC (a la 802.1ah) could
> be done but to be honest the IBoE spec that the IBTA came up
> with looks rather broken for routing.

Routing is out of the scope of the current RoCE spec.
And I do not see how .1ah would be relevant for this purpose.