| MCC's Phase V AM does not interface with DDM.
This is for efficiency reason. If we did go that route
we would be translating ILV into Itemlist and then Item list
into CMIP-ASN1. Instead we are going directly from ILV to CMIP_ASN1.
We are writing our own access routines.
DDM is certainly callable from MCC. If you want to call it synchronously,
it will hang until the request is satisfied. This is not acceptable
in the thread environment. If you want to call DDM asynchronously, you
will have to develop monitors around the call.
Hope I answered the question.
Arun.
|
| errr, ummmm, pardon me, but could I ask why one group decided to use an
ILV representation of data for its interface and the other selected item lists?
Are there really fundamental differences between the two that cause one to be
much better for the AM interface and the other better for the DDM interface?
curious,
Robt. P.
|
|
I can't speak for the other group (DECnet phase V), however I can
speak for MCC and have a few clarifying thoughts.
The debate of self describing data vs item list descriptions will
rage on for years to come and each application will need to decide,
based upon their requirements, which mechanism is appropriate.
Within MCC all data passed across the call interface must be ILV
encoded and all MCC management modules must conform to this
requirement. This requirement is based upon the need to compress
information into a single argument that can be passed across the call
interface, and allowed us to store information in a compressed form
within the MCC database. Passing information across the MCC call
interface in the same form in which it is retrieved from the database
provides a consistent view of the data to a management module. The
ILV mechanism was the best choice for meeting the MCC requirements.
Item list could provide a way of passing variable amounts of
information across the call interface, but would not address the
requirment of storing the information in the database in a compressed
form.
Within MCC, protocol transformation is accomplished within the access
modules (AMs). The DECnet phase V use of DDM is dictated by the phase
V architecture. The MCC phase V AM use of ILV is dictated by the
MCC architecture.
The DECnet phase V AM receives requests in ILV form as passed across
the MCC call interface. To convert these request into item list so
that we could use the DDM routines to convert them into CMIP request
would force us into another level of conversion. Instead we chose
convert the ILV request directly into CMIP request for performance
reasons.
I hope this clarifies the confusion.
Peter
|