[Css-dts] Significance of the functional group component of the Service instance Identifier

[Wolfgang.Hell at esa.int]

John,

While I'm writing this, I'm on travel and do not have the chance at this very
moment to check what is really contained in the CLTU Book. But I take your
word for it and CSTS / DTS at the spring meeting in that case may want to
generate one further Pink Sheet, as the example SII clearly refers to an RAF
SI. But that is just a side remark.

As regards the functional groups, so far they are not used in any systematic
manner. That is actually true for the complete SII, where from an application
point of view the only thing that matters is that the SII on the user and
provider side match. The actual selection of the provider, i.e.. the physical
entity that is supposed to provide the service, happens by putting the
correct value of responder ID and responder port ID in the SI. I personally
would think that also from an operational point of view it would be good to
really link the SII field values, among others the functional group, to the
values in responder ID and responder port ID. In this way, by looking at the
SII one can figure out for which context the given SI was created. As far as
I can see, we could apply such scheme without affecting the existing
implementations, as we only specify conventions in terms of SII field values
and other SI parameters. The exception is probably our SICM tool that we use
today to generate SIs from network schedules and mission profiles.

I don't know how urgently we need to come to a conclusion on this matter, but
I would certainly be happy to discuss this to further level of detail at the
Athens meeting.

Best regards,

Wolfgang




                                                                                                                                   
                      John Pietras                                                                                                 
                      <john.pietras at gst.com>         To:      css-dts at mailman.ccsds.org                                            
                      Sent by:                       cc:      CCSDS Service Mgmt WG <smwg at mailman.ccsds.org>                       
                      css-dts-bounces at mailma         Subject: [Css-dts] Significance of the functional group component of the      
                      n.ccsds.org                    Service instance Identifier                                                   
                                                                                                                                   
                                                                                                                                   
                      11/03/2005 22:56                                                                                             
                                                                                                                                   
                                                                                                                                   




Members of the DTSWG,
I have recently "rediscovered" that the Service Instance Identifier for
SLE transfer services has a Forward/Return Service Functional Group
component which appears to name a specific instance of a forward space
link functional group (fsl-fg) or return space link-functional group
(rsl-fg). The example from the FCLTU Blue (2) Book is
'sagr=xyz.spack=abcdef.rsl-fg=gfjdy.raf=onlc2'. The SLE transfer service
specifications further states that "the value of [the Forward/Return
Service Functional Group] is to be agreed between the user and the
provider."

Is this FG just a logical identifier that is included in the service
instance ID, or is the intention that there will be some physical or
logical entities associated with these FG names that must somehow be
configured to support the production or provision of the service
instance? Currently, SLE-SM does not recognize functional groups. I
would like to understand the intention behind this FG name so that we
can assess what (if any) changes are required in SLE-SM.

I apologize for not thinking of the ramifications of this FG component
when this shortened identifier convention was first proposed (and then
subsequently adopted).

Thank you for your consideration of this topic. I look forward to seeing
many of you in Athens (a mere month from today!)

Best regards,
John


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