Subject: [storm] iSER update request from Alex Nezhinsky on Datamover Interface

From: Mike Ko <[email-masked]>
Date: Thu, 20 Aug 2009 17:37:06 -0700

Alex sent me the following iSER update request:

> The spec uses the Data-Mover abstraction. No existing
> implementation adheres to this paradigm, opting for "on-wire"
> compliance. Moreover, this interface was never envisioned as a
> mandatory one, but the spec's language may be easily interpreted as if
> the Data-Mover interface is mandatory.
> There is no disclaimer explicitly stating that the actual
> implementation MAY choose NOT to implement Data-Mover interface, on
> the other hand, there are plenty clauses that
> use MUST referencing various Data-Mover primitives.
>
> Suggested solution: to add an introductory clause clarifying the
> advisory status of Data-Mover interface.

iSER is defined as a datamover in section 2.1.  As a datamover, it operates in conjunction with the transport layers to move the control and data information on the iSCSI connection.  It uses Operational Primitives for the communication between the iSCSI layer and itself.  In section 3, it was stated that "An Operational Primitive is an abstract functional interface procedure ... that requests one layer to perform a specific action on behalf of the other layer or notifies the other layer of some event."  "The abstract model and the Operational Primitives defined in this section facilitate the description of the iSER protocol.  In the rest of the iSER specification, the compliance statements related to the use of these Operational Primitives are only for the purpose of the required interactions between the iSCSI layer and the iSER layer.  Note that the compliance statements related to the Operational Primitives in the rest of this specification only mandate functional equivalence on implementations, but do not put any requirements on the implementation specifics of the interface between the iSCSI layer and the iSER layer."  It seems to me this text from section 3 as quoted above adequately clarifies the advisory status of the datamover interface.

Mike