[ofa-general] The significance of port numbers when creating QPs?

[Ralph Campbell]

ibv_query_device() will return the number of physical ports
but what you are probably asking is how to establish a
connection to a particular host. That is like hostname
to IP address which is accomplished via the connection
manager. See the documentation for librdmacm and libibverbs.

On Fri, 2008-05-16 at 13:27 -0400, Matthew Small wrote:
> So, when you are using an RC QP and attempting to write code for
> general hardware, how would you query the device to find which
> physical IB ports are available?
> 
> On Fri, May 16, 2008 at 12:50 PM, Ralph Campbell
> <ralph.campbell at qlogic.com> wrote:
>         It depends on the hardware you have in your system.
>         Most HCAs have one or two ports (a CX4 connector
>         for the IB cable). The port_num is a property of
>         the address handle (for UD QPs) or QP attributes
>         (for UC, RC QPs) which specifies which physical IB
>         port to use.
>         
>         
>         On Fri, 2008-05-16 at 12:40 -0400, Matthew Small wrote:
>         > Can anyone explain a little on the significance of choosing
>         a port
>         > number when creating a QP.  In particular, my implementation
>         has
>         > multiple QPs associated with a single PD and the only
>         attr.port_num I
>         > can  use to  initialize my queue pair seems to be 1.  Can
>         someone
>         > answer why this is and perhaps explain a general method for
>         choosing
>         > an available port_num.
>         >
>         > -Matt
>         
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