[ofa-general] Re: [RFC] host stack IB-to-IB router support

[Jason Gunthorpe]

On Mon, Mar 19, 2007 at 02:29:25PM -0700, Sean Hefty wrote:

> Based on previous e-mail threads, this is my plan for implementing IB-to-IB
> router support in the host stack capable of supporting RC communication.  Note
> that this work is part of the PathForward project aimed at supporting early
> IB-to-IB router development.  It is not intended to define IB router
> architecture.

Would it become part of openfabrics or just as a 3rd party
patch that interested parties could apply?
 
> 1. Extend struct ib_cm_req_param:
> 
>        struct ib_cm_req_param {
> 		struct ib_sa_path_rec	*primary_path;
> 		struct ib_sa_path_rec	*alternate_path;
> 	+	struct ib_sa_path_rec	*remote_primary_path;
> 	+	struct ib_sa_path_rec	*remote_alternate_path;

So the idea is that the CM REQ now uses remote_*_path to set the
fields? You intend to go with the notion that IBA specifies the
active sides sets the passive's LIDs in all cases?

> 2. Add an ib_remote_sa module.

It looks like there is a new wire protocol to support this?

Does it still work if, for instance, a modified active side tries to
talk to an arbitary existing target (such as storage or something)?

Broadly, do you describe having the active side send a seperate GMP to
the passive node to do PR queries and then sending a CM REQ?

> 3. Extend the rdma_cm route resolution to include remote route lookup.

This means produce a ib_cm_req_param using ib_remote_sa when
appropriate right?

How does this compare to the idea of using the LIDs from the REQ's LRH
on the passive side?

Thanks,
Jason