[Rdma-developers] Re: [openib-general] OpenIB and OpenRDMA: Convergence on common RDMA APIs and ULPs for Linux

[Sukanta ganguly]

--- Caitlin Bestler <caitlinb at siliquent.com> wrote:
>  
> 
> 
> ________________________________
> 
> 	From: rdma-developers-admin at lists.sourceforge.net
> [mailto:rdma-developers-admin at lists.sourceforge.net]
> On Behalf Of
> Michael Krause
> 	Sent: Friday, May 27, 2005 7:25 AM
> 	To: Sukanta ganguly
> 	Cc: openib-general at openib.org;
> rdma-developers at lists.sourceforge.net
> 	Subject: Re: [Rdma-developers] Re: [openib-general]
> OpenIB and
> OpenRDMA: Convergence on common RDMA APIs and ULPs
> for Linux
> 	
> 	
> 	At 06:40 AM 5/27/2005, Sukanta ganguly wrote:
> 	
> 
> 		Venkata,
> 		   How will that work? If the RNIC offloads RDMA
> and
> 		TCP completely from the Operating System and does
> not
> 		share any state information then the application
> 		running on the host will never be in the position
> to
> 		utilize the socket interface to use the
> communication
> 		logic to send and receive data between the remote
> node
> 		and itself. Some information needs to be shared.
> How
> 		much of it and what exactly needs to be shared is
> the
> 		question.
> 
> 
> 	Ok.  It all depends upon what level of integration
> / interaction
> a TOE and thus a RNIC will have with the host
> network stack.  For
> example, if a customer wants to have TCP and IP
> stats kept for the
> off-loaded stack even if it is just being using for
> RDMA, then there
> needs to be a method defined to consolidate these
> stats back into the
> host network stack tool chain.  Similarly, if one
> wants to maintain a
> single routing table to manage, etc. on the host,
> then the RNIC needs to
> access / update that information accordingly.  One
> can progress through
> other aspects of integration, e.g. connection
> management, security
> interactions (e.g. DOS protection), and so forth. 
> What is exposed again
> depends upon the level of integration and how
> customers want to manage
> their services.  This problem also exists for IB but
> most people have
> not thought about this from a customer perspective
> and how to integrate
> the IB semantics into the way customers manage their
> infrastructures, do
> billing, etc.  For some environments, they simply do
> not care but if IB
> is to be used in the enterprise space, then some
> thought will be
> required here since most IT don't see anything as
> being "free" or
> self-managed.
> 	
> 	Again, Sockets is an application API and not how
> one
> communicates to a TOE or RDMA component.  The RNIC
> PI has been proposed
> as an interface to the RDMA functionality.  The PI
> supports all of the
> iWARP and IB v 1.2 verbs.  
> 	
> 	Mike
> 	 
> 	 
> 
> I'd like to add that RNIC-PI is planning on
> explicitly defining some of
> these "obvious" dependencies 
> between the RDMA stack and the primary IP stack. For
> example, the RDMA
> stack cannot maintain
> any connection in a state that contradicts current
> IP stack routing. It
> has to adapt or break the connection.
> We can't have an RNIC that has its own ARP table
> that is not in sync
> with the host's ARP table.
>  
> An iWarp RDMA stack gains the benefit of many
> pre-existing network
> services (such as DNS, ARP
> and routing). But that also carries with it the need
> to not contradict
> those exisiting services. So it is
> both a benefit and a restriction -- and a major
> divergence from an IB
> RDMA stack.
>  
>   
> 

This is exactly what I was getting at and seems like
the RNIC-PI is already on its way to do that.


Thanks
SG

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