RE: [PATCH v6 01/26] IB/Verbs: Implement new callback query_transport()

From: Hefty, Sean
Date: Tue Apr 28 2015 - 02:14:27 EST

> > Keep in mind that this enum was Liran's response to Michael's original
> > patch. In the enum in Michael's patch, there was both USNIC and
> Right! That's why I'm confused. Seems wrong to drop it, right?

I think the original USNIC protocol is layered directly over Ethernet. The protocol basically stole an Ethertype (the one used for IBoE/RoCE) and implemented a proprietary protocol instead. I have no idea how you resolve that, but I also don't think it's used anymore. USNIC_UDP is just UDP.

> Well, if RoCEv2 uses the same protocol enum, that may introduce new
> confusion, for example there will be some new CM handling for UDP encap,
> source port selection, and of course vlan/tag assignment, etc. But if
> there is support under way, and everyone is clear, then, ok.

RoCEv2/IBoUDP shares the same port space as UDP. It has a similar issues as iWarp does sharing state with the main network stack. I'm not aware of any proposal for resolving that. Does it require using a separate IP address? Does it use a port mapper function? Does netdev care for UDP? I'm not sure what USNIC does for this either, but a common solution between USNIC and IBoUDP seems reasonable.

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