CF Requirements: 3) Slice Controller

GENI Control Framework WG Members, interested GENI participants, and
Jeff Chase of Duke,


A first DRAFT (v01.3) of the GENI Control Framework Requirements
document has been completed, and can be found at
http://groups.geni.net/geni/wiki/GeniControlFrameworkRequirements 

A discussion of the document on February 25, 2009 resulted in the
identification of 10 discussion items, which can be found at
http://groups.geni.net/geni/attachment/wiki/GeniControlFrameworkRequir
ements/030609_CFRequireReviewTopics.pdf



This email begins a discussion thread on:  3)  Slice Controller

I would like to invite Jeff Chase of Duke to begin the discussion, and
then others are invited to join in.  



2a)  During the discussion, the key elements in a GENI suite were
discussed, including the "triangle" of Researcher, Aggregate (with
Components) and Clearinghouse.

In his detailed comments for the document, Jeff suggested that a
"Slice Controller" should become a first-class entity (element),
associated with the researcher, that controls and monitors a slice.  
Jeff defined "first class" to mean that it is persistent, so that
other actors in the control framework, or slivers in its slice, can
send unsolicited messages/notifications to it.  And, it may respond by
taking autonomous actions to control the slice on behalf of an
experimenter.
Harry noted that this is in keeping with the current PlanetLab, the
ProtoGENI and ORCA prototypes.

2b)  The current DRAFT talks of:  
"A principal acting from a server utilizing a browser client or a set
of helper tools".  So, there is talk of a "server' and "helper tools",
but no slice controller.

2c)  Discussion:
All of the current prototype implementations include some form of
"slice controller" (or slice manager).
In PlanetLab, it is part of PLC.  
In ProtoGENI, it is associated with the Researcher.  
In ORCA, it is called the Slice Manager.  
All hold state specifying the slice.

2d)  A proposed change to the CF requirements:
Each suite includes one or more Slice Controllers
(this must also be reflected in the GENI System Overview)

Each slice controller:
Associated with one (or more) researchers.
Trusted to properly represent the researcher(s)

"First class" entity
Persistent, so that other actors in the control framework, or slivers
in its slice, can send unsolicited messages/notifications to it.  

Interacts with clearinghouse and aggregates.
Discovers, plans, requests, acquires, and controls resources from
aggregates.
Keeps state.
If gets firm reservations, it keeps a calendar of committed resources.

2e)  Continued discussion:
Is the "slice controller" always required in a GENI suite?
Must the "slice controller" be persistent?
Should the slice controller typically represent one researcher?  One
research organization?  Or?
Is it important to specify where it is located?
Do we need to define the interface between the slice controller and
the researcher?
How does the "slice controller" present a "trust assertion" to an
aggregate?



We look forward to a continuing, lively discussion, working towards a
'rough consensus".

Harry E. Mussman
Control Framework Systems Engineer

GENI Project Office
BBN Technologies
10 Moulton Street
Cambridge, MA 02138
(617) 873-4282 - Office
(781) 266-8479 - Mobile
(617) 873-4888 - Fax
hmussman@...
www.bbn.com



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