NPM/BAR glue schema minutes
---------------------------

EGEE4 conference 26/10/2005

UEDIN: Florian Scharinger (FS), Alistair Phipps (AKP), Charaka Palansuriya (CP)
DANTE: Anand Patil (AP)
INFN: Sergio Andreozzi (SA)

Glossary
--------
SR: Service Reservation
SA: Service Activation


General
=======

A glue schema "site" does not relate to a single network domain - it
is an administrative entity.

Updating the schema takes a long time - different people have
different ideas about how to do things.  However, the current version
is not "official" / final v1.

Jen Schopf is one of the main people that has influence over the glue
schema, and she should be convinced about the need for our proposed
changes.

If our proposed changes are not accepted for v1, Sergio will try to
include them in v2.

In the current version of the Glue Schema (v1) there are tables for:

Site     Service    CE    SE


Subnet Issue 
------------ 
When a job is scheduled, the actual CE/SE
which will be responsible for the job is not known, since the Grid is
seen as a single resource (ideally).  

That's why the question arose, how at SR stage the subnets of the two
involved endsites can be known.  The assumption was taken that the
site administrators will reserve SRs for the most likely connections,
though this approach is not very satisfactory.


Additions to Glue Schema
========================

NPM and BAR have similar requirements for the Glue schema, though they
differ slightly:

 - NPM needs to know the NPM service ID for a particular CE, SE.

 - BAR needs to know the BAR Service ID for a particular CE, SE and
   for a particular subnet.

Solution: add link to glue schema (table to R-GMA), either:

a)
---------------------------------------------------------
CE.id       Service.id
----------------------

Where CE.id is CE primary key, Service.id is Service primary key.

---------------------------------------------------------

b)

CE.id       Domain
------------------

Where Domain indicates a network domain within a site (corresponding
to a subnet with a unique access link to the external network).

AND:

Domain      Service.id
----------------------

---------------------------------------------------------

c)

CE.Id       Domain
------------------

AND:

Domain      NPM Service id      BAR service id
----------------------------------------------


Solution a) would only satisfy the requirements for NPM, since BAR
needs to located the correct RemoteBar by just knowing the subnet of
site2.

Solution b) would satisfy both, NPM and BAR, since the 'Domain' could
hold subnet information.

Solution c) would also satisfy both, NPM and BAR, but is more
specialised for BAR and NPM then b).

Conclusion: 
Both, solution b) and c) would satisfy NPM and BAR, though b) is the
more general solution, meaning that it is more appropriate and likely
to be add to the Glue schema specification.


Reservable Path
===============

For several reasons, it would make sense to add a "reservable path"
between CEs/SEs to the Glue schema.
The job scheduler could make use of this information to check if a
path between a certain CE and SE exists at all. Furthermore, this link
could be used to mark already existing SAs.

TBD. 


Open Issues
===========

What exactly should the 'Domain' field contain? BAR would need to
query subnets here.


Actions
=======

[FS/AKP] Speak to Jennifer Schopf about modifications of Glue Schema