[openib-general] [PATCH 0/10] [RFC] Support for SilverStorm Virtual Ethernet I/O controller (VEx)

[Yaron Haviv]

> -----Original Message-----
> From: openib-general-bounces at openib.org [mailto:openib-general-
> bounces at openib.org] On Behalf Of Rimmer, Todd
> Sent: Monday, October 02, 2006 5:46 PM
> To: Scott Weitzenkamp (sweitzen); Kuchimanchi, Ramachandra; Roland
Dreier
> (rdreier)
> Cc: openib-General
> Subject: Re: [openib-general] [PATCH 0/10] [RFC] Support for
SilverStorm
> Virtual Ethernet I/O controller (VEx)
> 
> > From: Scott Weitzenkamp (sweitzen)
> > Sent: Monday, October 02, 2006 4:22 PM
> > To: Kuchimanchi, Ramachandra; Roland Dreier (rdreier)
> > Cc: openib-General
> > Subject: Re: [openib-general] [PATCH 0/10] [RFC] Support for
> SilverStorm
> > Virtual Ethernet I/O controller (VEx)
> >
> > Is this communication protocols documented anywhere?  How does this
> > feature compare to IPoIB and SDP?
> >
> This protocol is distinct from IPoIB and SDP.
> 
> In brief:
> 
> IPoIB treats an IB fabric as a LAN.  As such it has UD semantics.
> 
> SDP essentially treats the HCA as a TOE and leverages IB's RC
semantics
> to emulate TCP/IP SOCK_STREAM sockets.
> 
> This protocol implements the interface to communicate to the
SilverStorm
> VEx Ethernet Virtual IO Controllers.  The VEx card presents a true
> Ethernet NIC to the host and essentially treats IB as an IO bus to
allow
> a host CPU to use the VEx card as its NIC.
> 
> Todd Rimmer
> 

Todd,

I'm trying to figure out why this protocol makes sense 
As far as I understand, IPoIB can provide a Virtual NIC functionality
just as well (maybe even better), with two restrictions:
1. Lack of support for Jumbo Frames 
2. Doesn't support protocols other than IP (e.g. IPX, ..)

1 can easily be addressed using IPoIB RC, and the question is if 2 is
really a problem (how many people use IPX or apple talk .. these days)
And if 2 is a problem why isn't it in a greater scope of supporting
Ethernet emulation even between any IB nodes, and not just from a host
to a gateway device.

If this is a real requirement, why haven't SilverStorm worked with the
industry and standardization bodies such as IBTA or IETF to come with a
standard and interoperable way to address it, and not just try and push
a proprietary driver and a point solution to the kernel.

I believe we should first see if such a driver is needed and if IPoIB
UD/RC cannot be leveraged for that, maybe the Ethernet emulation can
just be an extension to IPoIB RC, hitting 3 birds in one stone (same
infrastructure, jumbo frames for IPoIB, and Ethernet emulation for all
nodes not just Gateways) 

Yaron

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