[openib-general] RDMA connection and address translation API

Roland Dreier rolandd at cisco.com
Wed Aug 24 14:30:52 PDT 2005


    Roland> No, I think we just need to realize that a perfectly
    Roland> transport neutral protocol implementation is not
    Roland> achievable.  It's unfortunate that kDAPL fooled people by
    Roland> hiding the details of the wire protocol under a supposedly
    Roland> "neutral API," but the fact is that mapping an abstract
    Roland> RDMA transport to a real implementation will always
    Roland> involve arbitrary transport-dependent choices.

Further: if we would be willing to say that transport-neutral
protocols must use a "kDAPL wire protocol," then there's no problem in
defining that wire protocol to put the source and destination IP
address somewhere in the CM private data.  The current "kDAPL wire
protocol" happens to use ATS to try and achieve this (although it
doesn't handle the multi-homed case), but that is no more and no less
of an arbitrary protocol design choice.

So in a nutshell, my objection to using ATS is that it is an arbitrary
design choice that doesn't work as well as other equally valid choices.

 - R.



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