Subject: Re: [PATCH V2 09/12] net/eipoib: Add main driver functionality

From: Or Gerlitz <[email-masked]>
Date: Mon, 13 Aug 2012 11:33:18 +0300

On 12/08/2012 18:40, Eric W. Biederman wrote:
> Let me give you a non-hack recomendation.
>
> - Give up on being wire compatible with IPoIB.
>
> - Define and implement ethernet over inifiniband aka EoIB.
>
> With EoIB:
> - The SM would map ethernet address to inifiniband hardware addresses.
> - You discover which multicast addresses are of interest from the
>    IP layer above so no snooping is necessary.
> - You could run queue pairs directly to hosts.
>
> Shrug.  It is trivial and it will work.  It will probably run into the
> same problems that have historically been a problem for using IPoIB
> (lack of stateless offloads) but shrug that is mostly a NIC firmware
> problem.  The switches will have no trouble and interoperability will
> be assured.
>
> If you want to map ethernet over infiniband please map ethernet over
> infiniband.  Don't poorly NAT ethernet into infiniband.
>
>

EoIB is a valid suggestion and we will look into it as well, BUT:

Providing EoIB is a separate discussion, obviously defining and 
standardizing a new protocol takes what is takes (a lot of time, longish 
term effort), and will also take time to develop/debug/mature e.g as you 
mentioned, some of the features/offloads might require new NIC HW, etc 
-- compared to IPoIB which is here for many years

In practice there is already a huge install base for IPoIB software and 
hardware products, in different operating environments/OS. We can't just 
through away everything and tell people to replace it all with a new 
protocol, e.g. bridging devices, storage systems/appliances, VMware, 
Windows, .. systems in production environments --- so
the interoperability concern you've mentioned gonna hit very hard.

The eIPoIB driver comes to provide a way to work with IPoIB in 
virtualized environments, where still, the suggestions/concerns raised 
in this thread should be addressed.

Or.