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Date: Tue, 15 Dec 2015 18:05:48 +0800
From: Peter Xu <peterx@redhat.com>
To: Pavel Fedin <p.fedin@samsung.com>
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Cc: dev@dpdk.org, Victor Kaplansky <victork@redhat.com>
Subject: Re: [dpdk-dev] [PATCH 0/4 for 2.3] vhost-user live migration support
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On Tue, Dec 15, 2015 at 11:45:56AM +0300, Pavel Fedin wrote:
>  To tell the truth, i don't know. I am also learning qemu internals on the fly. Indeed, i see that it should announce itself. But
> this brings up a question: why do we need special announce procedure in vhost-user then?

I have the same question. Here is my guess...

In customized networks, maybe people are not using ARP at all? When
we use DPDK, we directly pass through the network logic inside
kernel itself. So logically all the network protocols could be
customized by the user of it. In the customized network, maybe there
is some other protocol (rather than RARP) that would do the same
thing as what ARP/RARP does. So, this SEND_RARP request could give
the vhost-user backend a chance to format its own announce packet
and broadcast (in the SEND_RARP request, the guest's mac address
will be appended).

CCing Victor to better know the truth...

Peter