[openib-general] IP addressing on InfiniBand networks

[Caitlin Bestler]

On 6/29/05, Kanevsky, Arkady <Arkady.Kanevsky at netapp.com> wrote:
> Most of the existing apps kernel and user space are based on socket
> addressing nad naming convention including IP addresses and ports.
> All RDMA APIs made a decision to only deal with IP address and hide
> IB/MAC
> addresses under the covers so Consumer do not have to change their
> existing IP addresses based setup.
> We will severelly hamper adoption if we request any changes to
> application
> addressing scheme.
> We should strive to the requirement that no ULP changes are needed
> in order to use RDMA.


I'm in full agreement, but want to add one clarification. The DAT APIs
do not require that the user work with an IP Address. They work with
an IA Address that has the same format as an IPv6 address and meets
all of the semantics of an IPv6 address. But we never *required* it to
be an IPv6 address. 

The actual distinction has more to do with IANA that anything visible
to an application.

There is one concrete requirement that the IA Address be unique
from the perspective on the host. That is, it cannot be a link dependent
address. The consensus was that link dependent addresses were
something foreign to current network programming and not something
that an application should have to deal with. Link-local addresses
are intended for bootstrapping, not applications.

An assigned GID meets all of the requirements for an IA Address.
I think taking advantage of that existing capability is just one of
many options that can be done by the IB CM rather than forcing
IB specific changes up to the application layer.