6'964 Pervasive Computing ContextAware Networking

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6.964 Pervasive ComputingContext-Aware Networking

• Stephen J. Garland
• October 18, 2001
• DRAFT
• MIT Laboratory for Computer Science
• Networks Mobile Systems
• http//nms.lcs.mit.edu/

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Sample INS Application FloorPlan
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Anatomy of the Demonstration

• Use of intentional names
• INS software
• Written in Java
• Located in ipaq/garland/ins
• INS documentation
• These slides
• See also ipaq/garland/ins/doc
• But the complete truth is in the source code

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Intentional Names
service camera location NE43 floor 5
room 504 resolution 800x600 access
publicstatus readyvspace wind

• Structure list of nested attribute/value pairs
• Meaning of attributes is application-dependent
• Currently special treatment for vspace
• Must be present to identify a virtual space
• Each vspace is a separate naming hierarchy
• New mechanism will replace it to help INS scale

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Intentional Name Queries
service printer location NE43 floor gt 3
floor lt 6 status queueLength lt
5 vspace wind

• Like names, but with wildcards, ranges
• Matching rules
• Values of attributes in query and name must match
• Attributes not in query or name treated as
  wildcards
• Matching is recursive

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INS Software

• DNR Domain Space Resolver
• INR Intentional Name Resolver
• Sample services and applications
• Floor plan application
• Location server (provides maps)
• Print server (provides lpr, lpq functionality)
• Camera server (provides images)
• INS client API the Application class

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Running a DSR

• Command java ins.dsr.DSR
• Usually run on a known host, dsr.domainName
• Can be run on a machine of your choice
• Need one DSR to
• Tell applications where to find an INR
• Enable INRs to announce their existence

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Running an INR

• Command java ins.inr.Resolver wind
• Here, wind is the vspace hosted by this INR
• Can replace wind by list vs1,vs2 of vspaces
• But some sample apps may not work if you do!
• Useful command-line argument -d host
• Use this if DNR is running on host, not
  dsr.domainName
• For running INRs, services, and applications
• Need one or more INRs to
• Accept service advertisements
• Respond to service discovery queries
• Forward messages via intentional names

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Running a Print Service

• Command java printer.LPRGateway
• Run in directory containing LPRGateway.conf
• Sample .conf files in ins/apps/printer
• Configuration file lists printer locations
• Improved design would dispense with .conf file
• E.g., by providing server with a configure option
• Print service provides a GUI for users

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Running a Map Service

• Command java locationserver.LocationServer
• Run in directory containing
• LocationServer.conf
• File tree with maps, coordinate information
• See samples in ins/apps/locationserver
• Intentional name for serviceservicelocationen
  tityservervspacewind
• Can ask for map of location or location on parent
  map datamaplocationmitbuildingne43data
  coordslocationmitbuildingne43
• Service responds with map or coordinates

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Running the Floor Plan Application

• Command java floorplan.Floorplan
• Run in directory containing Floorplan.conf
• Sample .conf files in ins/apps/floorplan
• Configuration file contents
• service icon-file handler
• camera ins-camera.gif camera.Receiver
• printer ins-printer.gif printer.LPRClient