DTNs and GENI Measurement
Will Leland
[email protected]
First GENI Measurement Workshop
Madison, WI
2009-06-26
Implications for GENI Measurement
• Looking at GENI measurement requirements and system
with some specific research areas in mind
 Disruption Tolerant Networking (DTN)
– Content-Based Access (CBA)
– Wider network science context
• Focus on
– What support do these areas need from the GENI
measurement infrastructure?
– What benefits might they bring to realizing that
infrastructure?
2
DTN Key Concepts
• Exchange “bundles”, which have explicit lifetimes
• Network not necessarily ever connected
– No need for end-to-end connected path
– Network opportunistically routes a bundle “toward” its
destinations
– Network holds a bundle till its lifetime expires
• Bundles have metadata
– Metadata may be more widely distributed than the data
– Data and metadata may have different access control
• Destinations can be described, rather than addressed
– Late binding of destinations
– Deliver to destinations that match description at any time
during the bundle’s lifetime
3
GENI as a Disrupted Network
• GENI can be a powerful tool for studying networks with
challenged components
• GENI slices can contain challenged components (e.g.,
sensors, MANET nodes, etc)
– Location, time synch, real-time access may be unavailable
• Federation implies subnets can join, leave, rejoin
– The measurement infrastructure itself may be disconnected
– A (logically) central repository for measurements may be
infeasible
– A researcher’s access may be intermittent
– Federated components may have constraints on what can
be measured or what measurements can be shared
• Technology, policy, contingency, …
4
Implications for Measurement Architecture
• Preserve characterizations of limitations in time &
location information
• Allow researchers to specify what characterizations are
needed and what limitations in characterization are
acceptable for components of a slice
– E.g., social role may matter more than physical location
• Extend definitions to cover challenged networks
– For example, a “link” may be a data mule
• How should one usefully characterize a grad student with a
backpack full of USB drives?
• Address disparate levels of what is being delivered
– How does the experimenter know a bundle has been
delivered? What is the definition of successful delivery?
• Exploit DTN technologies for collection, distribution, and
5
retrieval of measurement data
GENI Measurement Requirements
Some relevant requirements
• GENI System Overview GENI-SE-SY-SO-02.0.doc
Sec 10.1 GENI instrumentation and measurement system
(GIMS)
– Ubiquitous deployment
– No impact
– High availability
– Central repository
• GENI System Requirements Document GENI-SE-SY-RQ01.9, sec 7
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7.1-1: component measurements
7.1-3: link measurements "optical, wired and wireless links”
7.1-7: real-time access to measurements
7.1-8: component locations
7.1-9: time services: "a common timeframe for all
measurements, synchronized to within TBD microseconds
across the system"